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Review the market of whole Chinese digital television, the cable television (CATV) Digitization and IPTV differ from one another. The digitized train of cable television has been already started, will enter and accelerate stage soon, to be solved problem how accelerate and with what way accelerate now. The policy factor has hampered IPTV market's progress, but IPTV has already shunted in some customers. IPTV and direct broadcasting satellite TV form very great threat to CATV digitized market, force CATV digitized operator to speed up the steps of advancing.

There are its endogenous laws in new technical development, The wireless technical prosperity is because of people to the free pursuit. Freedom is innate needs of people like surviving. As people find the electromagnetic wave can help to get rid of the free transmit message of constraint of the cable, the desire of chasing freedom and primitive lets wireless Communication become more and more active, the cable can only be abdicated in the sky the sovereignty becomes the lonely underground worker. 3G, UWB, WLAN, GPS and digital television since the Er most early telegram, radio station develop, wireless technical development lets the transmissive application of information be becoming more extensive, bring an increasingly many brand-new experience to people. Wireless technology undoubtedly becomes the focal point of domain development of whole communication, and the focal point of Communication chip development is concentrated in the field of wireless Communication naturally.

Develop the source that the radio frequency is The wireless signal in MTT-S IMS sentence of coming back, it is a wireless foundation that develops too. Wireless radio frequency and market of microwave transmission are mushroom as it is employed extensively that wireless and technical, only market scale for 2006 first half of the years has already been close to 20 billion dollars. For the previous period, the international microwave conference (IEEE MTT-S IMS) on the 29th that the reporter has the honor to participate in and holds in San Francisco ,As annual radio frequency and microwave field highest seminar, the reporter has touched new achievement and new trend developed in wireless Communication at short range.

As the annual trade gala, this conference has become the stage where every large manufacturer competed for the new product, numerous novel unique powerful new product declare wireless flourishing development of field publicly show every large advanced scientific and technological capability of manufacturer. From these advanced products, the whole trend which we can develop by rough experiencing the Communication device, namely: The integrated level is higher, micromation, more steady, higher speed, energy consumption are lower and operation is more simple and more convenient. How to settle the integration of 3G and wireless network function well to become the new problem that the radio frequency manufacturer faces, the radio frequency of bimodulus of compatible 3G and wireless broadband receives and dispatches the new force that the products will become the market. Stronger and stronger with increase and mobile equipment function of the chip integrated level, under the intersection of chip and the intersection of volume and increasingly little trend, function module of radio frequency and other function module integrate to together gradually, become the new transmitting terminal functional unit. The source as wireless information, it is a indispensable assembly of all wireless products to make a start, under the requirements of high integration density, low energy consumption and products micromation, the mobile phone radio frequency (even a lot of radio frequencies) It is a overhanging technological innovation of this conference that function and controlling circuit are integrated on a packaged chip. Next development may digital control until clock circuit continue and radio frequency make a start, integrate to together, thus narrow the size, control the cost. At this conference, even enterprises propose integrating chance-over circuit of aerial and control module in the mobile phone deeply. With make technological to promote, radio frequency chip package volume already overall to carry out the transition from 130nm to 90nm, the function that and the single packaged chip realizes is increasing constantly. The size while the function increases of the mobile equipment is expected to shrink 20%~30% more on the existing foundation in the future. Future wireless product development will be paid attention to more and more intelligently. With user's requirement for product function being intelligent to design, become the intersection of Communication and the intersection of product development and essential constituent element already more and more. The intellectuality of the Apparatus of driving on the basis of sensor, analog digital converter and CMOS power amplifier etc. is designed and can be found everywhere at the conference, low cost, low power consumption, high capacity, short time delay characteristic let intelligent to design as the most beautiful a line of scenery at the conference. More overhanging, the multi-purposed single solution products based on single Apparatus can give play to the function of the products on the maximum intensity, have very high realistic meanings in saving the development cost, raising the commonability of the products.

Move the multimedia forum and canvass the mobile phone for August 10 of the following 2006 years, move the technological development forum of the mobile phone of multimedia technology alliance to hold in Beijing, chain relevant enterprises and institutions of industry such as domestic and foreign famous operator, chip manufacturer, terminal manufacturer,etc. have participated in the forum. At the meeting, from every profession and trade experts and scholars and professional put forward one's own view to the intersection of future and demand and trend that Mobile developed one after another. "The mobile phone has already become high equipment that rely on degree of people of information-intensive society, and the development of mobile phone can not break away from application, the future mobile phone should be supported from the simple pronunciation to the business scope with extensive wideband multimedia. " Research institute president Yang Ze Min summarize the telecommunications of Information Industry Department like this while mentioning the development trend of the mobile phone. The multinet roams ability, sensor system, ultra distance land network, mobile phone TV and support to technology such as bluetooth, amuses business and mobile phone in the hardware, software, opening, and Communication between being in the future man-machine Mobile develops the factor that must consider. What the movable termination is developed first trend is that the terminal wireless technology is multimode. The movable termination needs to integrate many kinds of wireless technology to support various movement data traffic, include integrated the intersection of mobile phone and the intersection of TV and such technology even, how guarantee various business of mobile phone smooth to switch over it is in the future mobile phone that develop subject problem that face in different rule. The second trend is that the terminal memory capacity is larger and larger. , various applied demands in order to meet various multimedia business' demands, including working, it is terminal memory capacity in including in if you can't store in inner on different fields, need by promotions greater. The third trend is to employ the diversification, this requires handling capacity of multimedia, calculation and storage capacity to all carry on greater improvement. Terminal become the recreation center, including built-in wireless music, mobile phone TV, networking the game, chat and blog function, but lack unitary media player and business adapter at present, this needs business to adapt ability to further improve. Meanwhile, also need to unify the terminal here and connecting relevant interface of technology in the development process, help to protect electronic device such as movable termination, PC, camera and carry on better information sharing.

While moving mobile phone forum of multimedia this time, the star of China parts the east executive vice president's solution of canvassing TV chip of the mobile phone of the musical sound a little. In terms of chip, mobile phone TV employ than ring tones and lens, MP3, MP4 integrate get mobile phone to be complicated. First of all, the mobile phone TV introduces the new Communication system in the mobile phone, not only a simple integrated multimedia application; Secondly, it takes lower power consumption to realize and watch the TV on the mobile phone for a long time; Moreover, need to support Off-The-Shelf many kinds of standards to coexist, the mobile phone chip solution needs the support functionality with multiple systems. The present common scheme is to make up the mobile phone TV module with two chips, through the exclusive chip received signal of the mobile phone TV, modulate the analog signal into a digital signal, then deal with the chip through transmitting the application to the multimedia of protocol layer, make use of business processing chip to carry on source decoding finally. This kind of method chip is bulky and with high costs, the most important thing is the power consumption is too big, must develop towards two even a chip scheme. Two key elements that the chip develops are the low power consumption and support the multiple systems, should accomplish low power consumption, not merely need to make a fuss about electric-saving of the chip, need paying close attention to the power management of different levels, system and the power supervisor modes of the chip, device. Chip built-in flexible, programming processor and DSP and processor technology that can be reconstructed are how the chip support a key to the multiple systems, need to guarantee to support different signal channel, source decoding in the middle of the chip, can be realizing Millisecondly and switching over. By the look of present technology, the signal channel has decoded and followed source decoding and can be integrated inside a chip, the technical development of the semiconductor can realize low power consumption, leave YF part outside the digital chip at the same time, have turned into the solutions of two chips.

The products are raw in order to comply with the trend forever that several big manufacturers air one's own views, so that had a say to the chip development of Communication most is the manufacturer which is in leading position of the trade all the time. What kind of scenery for this reason, we have interviewed several representative enterprises in the trade, future wireless development trend development will appear in the eyes of the manufacturer. As the intersection of industry and master wireless the intersection of chip and supplier, ADI radio frequency and wireless banking department develop a director Doug Grant to think The wireless chip has two main development trends. First, reduce the low-end " Exceed the low cost " The chip set cost of the mobile phone, the purpose is to develop the basic mobile phone with pronunciation and short message function and black-and-white display screen as low-cost as possible, but some mobile phone manufacturers find these chip sets can not provide a means for turning to the advanced function mobile phone and series of products. The second development trend is developing and improving the flexibility and chip set to strengthen function, can improve the attractive force of the mobile phone products in order to offer the advantages as many as possible, but the existing problem is that all functions need very high power consumption, thus will shorten the battery life-span of the mobile phone. So, the development trend of the chip set of the advanced function reduces the power consumption. Development trend and miscellaneous semi-conductive trade of The wireless device do not have too great difference: Reduce the power consumption, increase (and adjust) The function, lowering costs, and in order to reduce the material cost and reduce the up integration of the number of elements. There are different places a bit that is that a general trade development trend is to improve the speed - -Because frequency band use for most wireless system already, so it and general processor develop, require difference, in order to raise speed (a lot of the intersection of processor and already careful to know, get the intersection of multi-processor and promising than at a high speed the intersection of signal processor and system system manufacturer) for every product . Reach the mobile phone chip respect, the low-cost GSM/GPRS cell-phone form chip and capsulating the solution to already present only specifically. All " The single chip " The solution still needs external flashing memory and power amplifier, some of solutions adopt the external transceiver IC in order to reach the optimum performance, some also need external power management IC. 3G has already accorded with all 3G canonial chip sets on the market as the future focus of mobile phone development. Most UMTS chip sets are all directed against the advanced market, and TD-SCDMA chip set can be used in the mobile phone of all grade. The difficult problem of 3G is to find the appropriate function Apparatus in order to fully utilize 3G network to improve the advantage of the data rate, lower costs in order to make 3G technology used in the mobile phone of every grade at the same time. And the difficult problem of WiMAX is to choose this suitable technical best market segments, and develop the suitable chip sets of the characteristic and rational compromise of power consumption.

TI mainly nowadays offers The wireless technical key device, and construct various solutions in order to meet the future demand. Get most advanced, the intersection of function and abundant 3G Apparatus from traditional taking pronunciation as the core cellular telephone, TI has introduced extensive semiconductor and software solution, meets hand-held terminal manufacturers, moves the requirement of operator and application software developer. TI wireless production distribution and Zhang Lei, manager of market, take " The integrated level is higher, the power consumption and cost are lower " Have summarized the newest trend that Communication chip field researches and develops in the future. The original intention of DRP technological development of TI is in order to meet these requirements: Cost of lower solution and simplifying the bill of materials, higher system performance, longer battery life-span, smaller device size can realize the mobile equipment with more exquisite appearance, the ones that can integrate many kinds of radio components and can be put into making at once if market condition permitting in high flexibility hand in the key newly (turn-key) Type solution can wireless to be simplify design of designer and test job notably. As to hand-held terminal manufacturers, DRP technology can narrow the board-level space notably, and further lengthen the life time of the battery. Compared with the situation that traditional RF designs, DRP technology can save 50% power consumption, the intersection of bare chip and area and the intersection of system and board-level space,etc.. The integrated device contributing to lowering costs has characteristics such as capsulating, integrated memorizer subsystem and integrated power management device,etc. integratively. So the integrated solution, with cooperating with the single remote application processor scheme of the external modem to compare and have greater advantages, for example OMAPV2230 base band of TI can offer support for GSM/GPRS/EDGE and WCDMA at the same time, and in terms of a lot of telephones on of market at present, the above-mentioned base band standard remains each other independently. As the leading provider of chip of the mobile phone, Zhang Lei thinks the market of mobile phone will keep the fast development in two major fields, every one for cost getting ampler cellular telephone markets low-costs ultra of 30 dollar,among them can reduce an important developing direction by power consumption by a wide margin with at the time of cost, it can save area and silicon chip area of the circuit board notably. Another point of growth is a market of walkie music / multimedia cellular telephone, various consumption and employ in enterprises such as mobile televisions, 3D be had a look around game, E-mail, audio frequency and video attachment, Web and downloading and video conference,etc. last cellular telephone market new development power. Qualcomm begins to set foot in the chip development field of Communication on a large scale too at present as 3G canonial main patent holder. Research and develop the 3G mobile chip development of the focal point as to the Communication chip in the future, more representative to the clear experience to Qualcomm of the heart of the standard. The trend that the high pass thinks Communication chip field researches and develops mainly concentrates on the bipunctate. First, the chip of future generation will have stronger multimedia function, more sharp picture, more high definition. The function of the chip will support more sharp VGA display screen (VGA will be 4 times of QVGA definition now) ,Will also support the camera of 6 million picture element. Second, the chip is highly integrated. Qualcomm has been making great efforts to create the new movement function, and merge multiple functions on a kind of apparatus, thus push The wireless technology of the future generation to the new height constantly in the whole world. The mobile phone chip that we offered the customer is intact chip, all azimuthal solutions, all functions such as including the modem, multimedia function, radio frequency function, receiving the function, transmission function, energy consumption management are all integrated on a chip. Support the increasingly high multimedia function with the Communication chip, this evolution has put forward some new questions and challenges for the chip of the mobile phone too. For example, how to realize low electric consumption is a very important question. Qualcomm has three measures while meeting the challenge of this one: First, change software hardware, can reduce the consumption of the energy more the intersection of multimedia and the intersection of function and direct implantation chip; Second, importance of power management; Third, reduce the technology of electrical consumption, reach 65 nanometers more from 130 nanometer to 90 nanometer such as the manufacture process. On April 5, 2006, Qualcomm introduced 65 nanometers of MSM6800 chip set sample wafers directed against CDMA2000 1xEV-DO Revision A network ahead of time, treatment technology can highly support integrating, low power consumption, more small and more exquisite with abundant function apparatus.

In processor of the mobile phone, " Scorpion " of Qualcomm Move the microprocessor integrated Mobile Station Modem (MSM) The solution, compared with characteristic the power consumption is very outstanding, make the mobile phone set handling capacity compare favourably with PC. This kind of microprocessor still possesses accurate and complicated microarchitecture and advanced power management and designing technique of the circuit, the multimedia characteristic used for increasing newly but this is that one of advanced mobile devices of future generation is required importantly.

The demand for development of the mobile phone still keeps the fine linear characteristic while switching over with the multimode frequency band the multiband with the low insertion loss, this has promoted application and development of RF MEMS switch. As the new complicated wave is similar to WiMAX to add on the composite signal, the switching problem of the multiband becomes more outstanding. Can offer in the intersection of 3G and network that the whole world build on a large scale at present including data and request video in inner multiple operation, the development of the network has proposed the new challenge to the mobile phone designer. Wireless technical development has already made the mobile phone use 7 kinds of different ones line standard (frequency band) does not ,Including DCS, PCS, GSM, EGSM, CDMA, WCDMA, GPS and Wi-Fi (see Table 1) . Each kind has unique characteristic and restriction standardly oneself, and one's own peculiar problem has emerged. Micro-Electro-Mechanical System of the radio frequency (RF MEMS) Perhaps can help engineers to design and meet demands of integrated multiband keep the mobile phone of the long battery life-span at the same time as well as, in addition can also keep while reducing the mobile phone volume with increasing new characteristic constantly cheap. Nearly there are 100 components in the mobile phone, among them 75% are " passive " The component, such as the inductance or variable capacity. This kind of component of MEMS edition is expected to make the mobile phone make the volume smaller and the efficiency is higher.

Most mobile phones are adopted and sent / received(T/R) at the place where the aerial and surface of the mobile phone chip set have been connected on the market at present of current situation of the mobile phone The switch, namely a kind of frequency band switch and/or duplexer, as shown in Fig. 1. Use a T/R switch to still use the association of T/R switch to depend on the quantity of frequency band that the operator adopt. Every type in this kind of switch meets one or another canonial rigorous performance range, for example the clan standard of time (TDMA & GSM) that it is half duplex that T/R switch is adopted in essence . The standard of code division clan is suitable for the service jet of full duplex, so has adopted a kind of double -channel or multi channel duplexer. The multiband mobile phone can use all T/R switching elements of these three kinds of types in order to make up, guarantee the worldwide voice service.

Fig. 1 mobile phone typical antenna switch of massive synoptic diagram must be transmitted and up to 5GHz frequency and support insulator upper silicone (SOI) Device, compound semiconductor, such as GaAs (GaAs) Or intrinsic barrier diode. Power extremely low (15mW) that this kind of switch dawdles ,The isolation is fine (according to capsulating, reach 35dB) ,Insert and consume low (0.8 dB)s . GaAs and intrinsic barrier diode scheme dealt with the power and the reason of the flexibility has been favored all the time for a long time. SOI has offered the breakthrough point for entering this highly competitive market in new technology, but if does not adopt new designing technique, it is very difficult that SOI surmounts the scale of 4GHz. Some finally, canonial CMOS, from apply to, still there are distances by these market, but smaller chip architecture will make manufacturer possible to offer and transmit the high-frequency products up to 2.5GHz.

It is RF MEMS switch that T/R switches over and switches over a kind of alternative scheme switched over to T/R with the frequency band. The power consumption little switch, insert and dawdle low, the isolation is high, and the linear characteristic is excellent, Table 2 has compared RF MEMS side by side with GaAs and SOI technology. Because the advantage that space and power were saved stressed very much, T/R switch was once the developing focus that RF MEMS developed the manufacturer in the past. Because the popularization speed of RF MEMS switch is slow and T/R switch has advantage of price competitiveness, make the price of RF MEMS not accepted by market. At present, new switch application - -The frequency band was switched over and already presented, the compatible demand as to mobile phone has already forced the mobile phone manufacturer to implement Tri-bands, four frequency bands and multimode schemes. S it is more complicated to switch over making and develop a kind of possibility of the world mobile phone to hold all frequency bands i singly among many kinds of different wireless frequency bands. 2 of Fig. shows to turning on or off the potential requirement for the switch that the father collected as T/R. RF MEMS can offer a kind of potential alternative scheme for Off-The-Shelf solid-state switch, but the one that mainly develop the obstacle and IC originally and face is similar to competition situation of the discrete semi-conductive electronic device: Cost, manufacturability, reliability and characteristic.

Fig. 2 is suitable for the embodiments of one kind of canonial multiband switches of mobile phone of various kinds

RF MEMS brief introduction MEMS technology can trace back to 1970 times, in electron and Hi-Tech trade, MEMS switch thought to be hopeful to enter and switch over the market all, only switch over the development blockage that development caused MEMS switch of the market slowly after 2000. But the market of mobile phone is thereupon question of the multiband of appearance / multimode mobile phone while increasing continuously, this impels industry to pay close attention to switching over other characteristics of using MEMS and MEMS again. RF MEMS switching element is similar to the mechanical relay, but the structure is generally in submillimeter or size of hundreds of microns. This kind of size makes this kind of device attractive, because they make it become possible to obtain ideally and take up 1mm2 or comprehensive switch scheme of a smaller space. In addition, this kind of switch can change and produce a lot of miniature application, such as delay cable and switched capacitor network. In theory, as to all right regular transmission and Apparatus to control 50GHz signal, RF MEMS technology can surmount the semi-conductive characteristic of the high speed, but a lot of factor restrain feasibility of RF MEMS until mobile phone employ, manufacture process, capsulate (the intersection of airtight and sexual isolation and parasitic effect) from , control voltage, switching over the life-span to circulate (the contact is bonded) for a long time , switch over the speed, RoHS compliance (the temperature of return current) And Manufacturing cost. There is not too much difference, but the requirement for dealing with RF power between RF MEMS switch and mere MEMS switch, in order to limit and reduce the electric current and impact on contact of switch of heat turned into, the designing technique adopted must be done the slight change. Typical RF MEMS switch roof beam with a kind of suspending wall beam (a kind of one that rivets on a point hangs) ,And utilize static or electromagnetic to drive. The stylus lies in each suspending wall beam " Float " One end,and it adopt conductor metal getting getting commonly more used in in semiconductor more manuafcture generally.

Problem and the solution do the stratification structure of the composition on crest of many kinds of substrate to makes RF MEMS device. The option including semiconductor made is processed, generally incline to adopt the most common method based on silicon or ceramic base crystal plate. Ceramic base method side may relatively your, but it is simple and convenient to capsulate. MEMS switch can be adopted and included polycrystalline silicon and GaAs (GaAs) Make in any semiconductor Engineering nearly inner. The planarity that the subject problem while making is the substrate, planarity is to form the stable level layer and construct every kind of structure for the litho process that adopts in the craft. Standard silicon is the extremely good choice, because the crystal plate polishes the process is this a technological part. The ceramic crystal plate seldom polishes or ties, added this process toing increases the overall cost that made on crafts, this makes it seem a bit expensive to employ to the mobile phone on the basis of ceramic RF MEMS conversely, thus has inhibited application. The common characteristics of solid circuit and RF MEMS lie in they have different conductors and insulating material layers. Main conductor material in aluminium and present copper has already been processed as silicons. RF MEMS develop manufacturer turn into, produce static or electromagnetic field required metal layer come, drive or promote the suspending wall beam by these conducting materials. But the contact of the switch must be made in order to finish the required circuit passway in the mechanical switch of high material of electric conductance characteristic. At present, it is the pure gold to conduct materials chosen. Pure MEMS and professional wafer manufacturer use gold in their process, this has opened up possibility for development of the device. GaAs and CMOS development with new manufacture process indicating the complete works become control and switching functionality are hopeful.

It is master considerations in T/R switch reseach that the static of Fig. 3 RF MEMS switch drives the synoptic diagram to capsulate the cost and magnitude. The demand for T/R switch is large, the cost reaches the level of several dozen cents, this makes RF MEMS difficult used in many kinds of application types. Meanwhile, the encapsulated choice is restricted, because RF MEMS switch must work the movement device in the clean environment. Generally adopt the ceramic packaging of the gastight seal, the reason is that it can protect the driving mechanism, but capsulate the plastic mould that the cost is much higher than the general GaAs switch and the standard semiconductor component adopts. Because the material and assembling the cost and reason of the cost, pottery encapsulated price and encapsulated price difference of plastics are nearly 5 times. On the other hand, the conventionally plastic price is lower, but can't fully isolate with the environment in order to avoid pollution. Typical ceramic packaging is similar to SAW (the surface acoustic wave) Ceramic packaging that is adopted in Shaker and electric-wave filter. They are formed by a ceramic substrate with thorough fare and a ceramic cover plate. Only this kind of cover plate generally occupies the large departmental cost that this kind of capsulation selected. The cost exists more cheap and capsulating more novel candidate scheme, can let RF MEMS solve the mobile phone problem. This kind of method including chip level is sealed (the excessive mould) And the method similar to chip level packaging. The chip seals many kinds of methods, include producing a layer of semi-conductive insulating layers or depositing a layer of membrane on the device. Excessive mould (overmolding) Can produce by semiconductor technology or can deposit as a floor of membrane. No matter which kind of situation, this craft forms the gastight seal which protects RF MEMS, and got rid of more expensive ceramic packaging. This kind of method may be the most promising, because it can make manufacturers seal RF MEMS in plastic capsulation, and plastic capsulation is easy to obtain and having numerous SMT structure. Control and RF MEMS device general in load power adopt a in the electromagnetism or static to drive in mechanical way. It may be that the machinery switches over the simplest method that the static is driven, but it needs higher voltage to produce strength to drive the suspending wall beam. This kind of method should produce one and charge the field (very like a electric capacity) Make the suspending wall beam deflect, such as Fig. 3. The question is that MEMS switch needs larger voltage to turn into the required electric field, but the driving voltage has already been dropped from 100V to 50V. In addition, the power that arise from electron transfer turns into the reason of heat, some structure (according to designing) Can't deal with heavy current above the 500mA, so driving voltage have, situated in into electric current (DC) In order to avoid causing destroying to the driving mechanism. The mobile phone does not have this kind of voltage, so MEMS developer must offer a kind of measure of trading off, make RF MEMS turn on or off to work with much lower voltage, can adopt DC-DC voltage change to solve this problem. Integrate through the higher intensity, the voltage changer and all right and high-voltage RF MEMS device of logic control unit are integrated together in order to produce a low-voltage scheme, as shown in Fig. 4. CMOS can be realized to combine to make with MEMS, but the driving mechanism of MEMS needs good contact material, such as gold or gold alloy. Gold deposit in surface of chip as the intersection of chip and bonding material generally, but complicated between the semiconductor layers gold implantation, must revise the general manufacture technological process. Metal working obstacle and used for high voltage transistor of the inverter of voltage usability of skill make it complicated not to integrate stock RF MEMS switch.

Fig. 4 high voltagetype RF MEMS switch is varied into a device monolithic microwave integrated circuit of low-voltage (MMIC) And many chip assemblies (MCM) Integrate a plurality of chips in the transfer pair monolithic microwave integrated circuit of voltage (MMIC) carried on next to RF MEMS switch while capsulating in one And many chip assemblies (MCM) It is influential. Essentially, the goal is to realize the switch scheme that the complete works become promptly of a one piece. The one illustrated in Fig. 4 is the final route to become of leading to the complete works. So long as suitable for processing, it will be out of question to offer RF MEMS switch of the low-voltage.

The long-term switch life-span circulates and switches over T/R switch general in speed in its life time during this period, switch over period to estimate for about several hundred million times, it can last 2~4 years to switch over circulation. But the life-span circulate, perhaps can get to change and change earnestly heavy current in the intersection of low-voltage and lower under-current. Before using EOL, reachable tens of billion times under the non-loaded and condition at present of movement of RF MEMS switch. But while changing earnestly, the circulation of life-span can be dropped to for several hundred million times. This makes RF MEMS turn on or off and has already been used in T/R on-off application. In addition, the GSM/GPRS cell-phone inner T/R switches over the speed and requires the seamless conversion that does benefit to receiving and dispatching within several dozen nanoseconds, the cellphone subscriber can not pay attention to the difference of conversation quality while talking and answering. And the switch speed of RF MEMS device, within several dozen microseconds, this should use to T/R switch slowly very much. On the other hand, as a kind of frequency band switch, RF MEMS device has double advantage of switching over the speed and changing the life-span earnestly, this makes it suitable for this kind (frequency band is switched over) Application. The switch speed of the frequency band does not need to be a lot of times faster than T/R switch. It once choose frequency band, this kinds of switch on one kind and corresponding" throw " (" The location " )Keep connecting it until detecting another frequency band or needing another frequency band. In the typical multiband is employed, frequency band switch, duplexer and/or T/R switch use together. The frequency band switch functions as router, it lets other components carry out required filtering and frequency band transmission function. Because the frequency band switch is an inner additional component in the signal channel, it must scarcely influence the overall performance of each frequency band, because RF MEMS switch low power dissipation, size little, insert and dawdle low and the isolation is high, become the ideal selection scheme.

The clock sinewave generator adjustable, based on electric-wave filter can make a resonator closed in the feedback loop shake. The sinewave generator in Fig. 1 utilizes this, thus avoid the need which sets up a amplitude control cycle. This kind yes Reagon (Regan) The circuit that slightly makes an amendment and becomes on the foundation with open cycle of syntony is that clocks are adjustable, and can produce sine and cosine to export.

Band-pass cycle LTC1060 switching capacity filter of Fig. 1 Regan syntony is constructed and built into one Q =10 adjustable type band-pass filters of clock. O1 presumes the frequency of this electric-wave filter as 100kHz, thus has produced a 1kHz band pass. C1 that the use sine is lost and turned on or off inputs the offering rectangular wave driving signal to the electric-wave filter in regenerated form. This cycle is self hold type, therefore has produced the serial sine wave to export on the indication point. Zener that C1 outputs bridges the square wave amplitude that clamping action has exerted to the electric-wave filter steadily, have realized the stability that the sine wave exports. This formal amplitude control removes AGC cycle stabilization time and potential unstability. Realize bandpass tuning by changing the clock rate of O1, shift during tuning and after tuning. Fig. 2 shows the working waveform. Export (sweep the mark A) the clamping of C1 The band-pass filter responded to has produced the sine (sweep the mark C) And cosine (sweep the mark B) Output. Distortion of relying mainly on the fact that the electric-wave filter clock remains (sweep the mark D) It is 2%.

Fig. 2: Encourage the pulse (Zener to clamp the output to the cycle of C1 by force, sweep the mark A) The band-pass filter responded to has produced the sine (sweep the mark C) And cosine (sweep the mark B) Output. Distortion of relying mainly on the fact that the switching capacity filter clock remains (sweep the mark D) It is 2%

The clock is adjustable, the table look-up memorizer produces a variable frequency sine wave regularly continuously through encoding a piece of sine on the circuit of this of sinewave generator based on memorizer. Changed the state of this memorizer into the analog output by one DAC. An advantage of this method is that it can make the frequency and amplitude alteration command fast, high to protect and really respond to. It is specified to set as and is controlled in by its figure O1 one of 3 kinds of output frequency is responsible for carrying on definite time (Fig. 3) to 74HC191 counter . These counters have connected one in parallel specially in order to produce for load 8 (256 kinds of states) Sine wave of numeric coding but 2716 EPROM of programming. By Sean Gold and Guy M. This procedure that Hoover develops is shown in Fig. 4. 2716 parallel outputs are to one DAC feed, in order to produce the analog output.

Fig. 3: The driving sine code memorizer of the counter has produced 0.75% distorted sine wave through D/A converter. The controlled LTC1799 oscillator frequency in digital input has presumed output frequency

Fig. 4: The ones that are used in the sine wave generating code picture 5 of the memorizer sweep the mark A to export for the sine wave, tuned in this occasion to 60Hz. Show as, sweep mark B distorted to remain, commit by clock mainly, the magnitude is about 0.75%. In Fig. 6, digital input changed output frequency as 400Hz suddenly, then resumed it to 60Hz rapidly. The frequency shifts succinctly agily, there is no outside weight or unfavorable characteristic. The amplitude finished by driving the reference input of DAC shifts (see LTC1450 data list) Have similar good operating characteristics. As Fig. 7 shows, the amplitude of sweeping mark B has responded to DAC reference input step of sweeping mark A accurately. As noted previously, have not controlled the cycle time constant to contribute to realizing the response without deterioration.

Fig. 5: The sine wave is exported (sweep the mark A) And distorted (sweep the mark B) . The weight correlated to clock is in distorted China very obviously

Fig. 6: The fast oscillator frequency shifted to realize the succinct and agile sine wave output frequency alteration

China has already become the market of maximum of the movable termination, but quite a lot of persons have not chosen the radio service, so expect the market will continue increasing. There are two kinds of driving force in the growth of the market: First of all, a big chunk, especially rural user will be from developing benefiting in the low-cost mobile phone. These the ABC of mobile phones of grade are mainly used for conversing, though the function is limited, will make more persons benefit from cellular telephone. In fact, here in the res. area of some wired Communication service, a lot of potential users will choose to move and serve to replace the cable service. In addition, once 3G licence is released to the operator, will present the new service in these new high speed networks, drive Off-The-Shelf mobile subscriber come on the intersection of staging and mobile phone of them in order to utilize new service these. Need to pay attention to too, the mobile phone in the 30% of whole world is made in China at present, domestic manufacturers have already captured significant market share. The further development of these manufacturers will come from and continue expanding the domestic market, and increase the export of the overseas market. In order to meet change and consumer of the market condition to new function and the Multiband, demand for operating the mobile phone of multi-mode, need to lower costs and shorten the time to develop the new product. In order to satisfy the support to this kind of demand, the fast development that the chip supplier often offers the reference design in order to hold the products. The reference design of a kind of typical 3G mobile is shown as in Fig. 1.

A development trend of The wireless handheld devices of SoftFone-LCR reference design which Fig. 1 ADI Company develops for the TD-SCDMA cell-phone is emphasizing the global commonability, size and power consumption, including a series of customer equipment (UE) while being apt to produce and exchange the staging Function,such as telephone, PDA, it is advanced audio frequency and video it serve and a lot of new idea. As to the mobile phone of new generation, obviously need to support the multimode and different interface operation in the sky. For example must coexist GSM/GPRS and the intersection of TD-SCDMA and modem in one mobile phone. In addition, the situation that we will often face many kinds of movement Communication standards and The wireless connections standard coexist, such as Wi-Fi, UMA, Bluetooth, these standards are being merged in UE gradually. In the multi-mode UE, not merely may change the input unit correlated to interface standard in the sky, and may carry out the function of any application layer by downloading the executable procedure. The critical technology foundation of realizing this kind of goal is: Divide UE system function that will be offered, the high-efficient systematic chip (SoC) supported effectively Realization,it is flexible extensible architectural in sums. However, no matter according to technology or economic angle, current situations of the movable terminations have all restrained us from being close to the intensity of this goal greatly. The multimode solution that the earliest economy is feasible depends on the extensible monomode scheme, it is actually same while capsulating two independent designs to a great extent make up. The concept of totally programmable UE will be according to the gradual progress progressively of a series of step, from choosing the hardware to begin, develop into but the intersection of reconfiguration and hardware, perhaps until future develop into, up to at all from software implementation a certain when but reconfiguration. In the course of transition, some particular the intersection of function and of UE will go through than other part programmable of intensity more. A lot of functions are all to perform and enter the programmable form from the fixed form to a great extent, among them some functions contribute to realizing this kind of transition such as function correlated to signal channel and speech coding naturally, but the miscellaneous function needs a slow transition course such as RF and composite signal function.

Wireless mobile phone architecture- Platform digital basedand of base band (DBB) It becomes key composition of The wireless mobile phone that the platform is programmable with his maximum. To different UE structure and integrated level, DBB includes a series of intact one perhaps Integrated composite signals (digital-analogue converter and analog-digital converter on-chip, and a lot of auxiliary and speech frequency band converters) Baseband processing function. Used for DBB structure of wireless Communication usually depending on the multi-core platform, including the kernel of programmable DSP and MCU and directing against the particular wireless canonial specialized hardware function module (accelerator and coprocessor) And the built-in memorizer of high capacity. The specialized hardware usually includes exceeding at present DSP kernel integrates available some processing units which need high speed and complexity operation for the mobile phone, slightly cite several examples, the code rate is dealt with (such as RAKE receiver) , honeycomb unit search for, the intersection of route and search algorithm, the intersection of turbo and decipher, and Fu set up the leaf to vary fast. DSP is always in DBB structural core. Have offered multimode a lot of advantages operated for DSP that The wireless terminal is designed, including DSP carries out and faces the ability to control the task, high-speed arithmetic capability, increased fast memory capacity and I/O bandwidth (an internal memory and interface used for an external memory) , number of times and improved power supervisory function of fast interrupt response which guarantee DSP system performance. In the past few years, channel coding and a lot of function in the speech coding from hard to connect collinear ASIC with, realize, change into in software implementation that carry out under DSP totally already. We expect to utilize structure advantage and technical advantage of semiconductor of DSP to make this kind of trend continue developing fast. The the intersection of development and route have, confirm in the line standard in a new one already, such as the intersection of China and some EDGE of district (improve the data rate GSM to serve) ,DSP encoded signal channel and balanced required computational capability has already been far greater than the requirement for GSM/GPRS far. The advanced DBB platform benefits from such as Blackfin processor kernel, it can be through offering most channel equalization algorithms (such as filtering and grid decipher) of support Instruction set last problem that is new. Look forward to 3G standard, DBB platform is besides needing more complicated MODEM modulate-demodulate function, there is drive of new type business, such as the video business. Blackfin nuclear handling capacity make their in SoC but also can utilize architecture of innovation their totally use the software method fully in the intersection of software and platform in the processor Realize the terminal installation of TD-SCDMA.

SoC complexity and functional development trend state as before, the realization of high-efficient SoC is to promote integrating the critical technology towards development of low-cost solution of the multimode mobile phone. The available solution contains the whole IC kind at the market now, mainly divide according to as follows: The division of the chip set, the structural basic function of DBB system, the technical usability of the semiconductor, division of Communication function and application function. The division of the chip set depends on that different that designs the field (such as RF, composite signal and DBB technology) to a great extent The supplier's technical capacity. The division of most chip sets usually divides RF transceiver into a chip independent of composite signal and DBB according to the manufacture process, and usually choose different crafts in order to realize suitable cost, characteristic and listing time the most. Put out recently " The single chip " The solution integrates RF function on slice, this usually needs 90 nm even smaller geometric dimensions craft, and utilized the enhanced digital means in RF design. This kind of form chip solution (usually still need single chip to offer power amplifier, power management and flashing memory function) Have less fixed function on flexibility and more slice, mainly orientate as the market of low-end. From the viewpoint of architecture, always there is a problem of trading off between flexibility intensity and integrated level. Because multimode and terminal demand, propose more high requirement to the integrated level level of already quite high DBB function of complexity, integrate additional digital function, influence cost their hardly, depend on slices of size of internal memory mainly usually effectively. Very see several DBB of a million logic gate designed often now, they can support bimodulus Communication function and other application functions. Communication function and application function take, divide into, lead to the fact different SoC choices of realizing scheme, integrated unit (including multi-mode Communication function and typical audio frequency and video application function) of the monobloc in the same chip Reach Communication processor and employ the melting and dividing physically of the processor. Though SoC has been offered for accelerating design cycle " It is essential " The condition, but an important one is to emphasize " abundant " that stability and completeness of the software bring Condition. The efficiency of software design will influence cost and power consumption of The wireless terminal directly, a structuring design method can make the complicated one have no support and maintenance authorized and mutually tested using sex in Communication of line style to easier.

The intersection of SoftFone and the intersection of digital basedand and until to complicated for system partitioning and the whole visual angle that support of SoC to come, it watches SoftFone to be one very good example in architecture architecture. The structural flexibility of this system makes the terminal installation trader develop different products, and interface standard come, develop one's own different products in the sky to a different one on the basis of using the same kind of hardware platform. The structural expansibility of SoftFone system can integrate the additional hardware module growing with each passing hour in order to support new application, it can debug the mechanism through being embedded to offer the support of structuring for modularization software.

Fig. 2 SoftFone architecture SoftFone architecture is based on RAM, it allows one by the hardware platform of the soft configuration, thus allow to increase the new function in order to meet market demand, can upgrade the control software in order to keep up with The wireless canonial gradual progress at the same time. So, the method based on RAM has shortened the listing time of the end product. Another structural important characteristic of SoftFone system is the modularization, it allows to replace DSP or MCU kernel into the stronger processor kernel, and can offer and increase new having the interface outside. This kind of architecture can shine upon realizing two processors to all peripheral hardware and on-chip at the same time and totally even visit of an external memory through the general unitary memorizer Q. The visit to the memorizer is to pass the bus arbiter (BUS ARBITRATION MODULE) Finish, thus has guaranteed that be able to realize the throughput rate needed in interconnection of nuclear seamless in the processor. System include sufficient cache at the same time, until real-time nature the intersection of function and essential application win the characteristic as best as possible from each kernel for require.

Karl's PowerQUICC Communication processor has been widely used since putting out to fly and think, since in the past 11 years, the processor module of Communication (CPM) As the major application of Communication based on PowerQUICC framework, meet a developer to the protocol processing demand for system design. PowerQUICC framework adopts a PowerPC core, is used mainly in the control plane dealing with and independent CPM based on RISC, run with the peripheral device and handle the task and a plurality of Communication protocols (ATM, Ethernet, HDLC) Thus coordinate and work with PowerPC CPU concurrently. Increase to merging, compatibility and efficient demand of economy day by day with the Communication skill, reduce cost of the wired and wireless accession equipment of future generation,etc. to require obviously day by day. For these demands of compliance, flying and thinking of Karl puts out brand-new QUICC Engine technology on CPM technical foundation. QUICC Engine technology is flying and thinking of Karl's Communication engine of future generation, aims at lightening the treatment task intensive in bandwidth from control plane CPU or DSP. It is in processor series MPC8360E PowerQUICC II Pro that it is adopted for the first time that QUICC Engine is technical, used in, fly to, think Karl's processor system framework while being other already at present. It can support many kinds of Communication protocols and functions, including layer one physical interface through the microcode, the 2nd layer ends, transmits and intercommunication, the third layer of intercommunication and transmitting, the 4th layer of identities is discerned and transmitted, IP / Ethernet, ATM TM and service quality. QUICC Engine can and compatible in based on PowerQUICC processor existing software product in technology, software designer can utilize Off-The-Shelf code library, thus reduce the system cost.

Merging, compatibility and high cost efficiency in order to help manufacturer's efficient use network and technical integration, reduce the development cost of the apparatus, develop the broadband technical equipment of the future generation high-efficiently, QUICC Engine offers the following characteristics: The ends of intercommunication of agreement and 2Gbps up to 1.2Gbps are dealt with. Intercommunication can save the programming work of the agreement, reduce from ATM, TDM and other agreements to the transitional cost of IP network. QUICC Engine can realize the high bandwidth is interconnected, does not need to take up CPU resources, thus improve the power consumption of overall performance degradation. Various canonial extensive integrated interface, such as TDM, Ethernet and UTOPIA interface. Reverse multiplexing (IMA) of ATM adaption layer, ATM And the conformance agreement of other agreements is implemented. In order to realize economic efficiency, systematic (SoC) on flying and thinking of Karl to offer slice Integrate, make QUICC Engine can be optimized for a series of application. To retailing and the user apparatus, QUICC Engine can allocate a RISC core, in order to help to lower costs. Extremely high bandwidth should use and, can allocate a plurality of RISC cores for needing. Require, can increase or reduce common Communication control device according to the intersection of port and density And multiple channel Communication control device (MCC) Quantity.

QUICC Engine technical application series MPC8360E PowerQUICC II Pro of giving an example adopts QUICC Engine technically to fly and think of Karl mailing address as the first Paying attention to device products, this series are based on e300 PowerPC systematic platform on block, including MPC8360E and MPC8358E processor, each processor has QUICC Engine technology to offer support, possesses the characteristics of Integrated security engine. The goal of PowerQUICC II Pro employs including: IP DSLAM, IP pronunciation (VoIP) System, 3G wireless infrastructure, passive Optical Network (PON) The apparatus, multi-service insert the node (MSAN) And small and medium enterprise (SME) Router,etc.. The market of Apparatus as networking of MPC8323E processor to consumer and SOHO but series MPC8323E of the design have adopted more pointed QUICC Engine technology Simplify the edition, it is the house to include one specially and SOHO networks and employs the 32-bit microcomputer RISC engine optimized. MPC8323E processor series can offer remarkable characteristic and flexible connection choice, suitable for house, SOHO gateway, wireless access point, virtual private network (VPN) , the router of fire wall and various IP service equipments. Through PCI interface on one, can support printer USB 2.0 line concentrators, network attached storage and media's server application, and adopt WLAN and WiMAX technical wireless connections. MPC8323E processor can also be used in other application beyond the digital family, such as DSLAM circuit card, industrial control, tests and measuring device. The internal characteristic of PC8323E makes it very suitable for various network Communication application. In SOHO router is applied to SOHO router and employed, MPC8323E offers SOHO way all dealing with and agreement function needed by device. It adopts QUICC Engine TM technology, through LAN and long haul network interface, uses the internet protocol (IP) Transmit the pronunciation, data and video flowrate. On the end of LAN, one UCC is used for being connected to 4 port fast Ethernet switchboards. A Ethernet interface is used in the up-chain, interface of one TDM offers leased line E1/T1 connecting or ISDN to connect. One UCC is used as ATM interface, support unit AAL5 to share, in order to offer the dialing ADSL to connect. But the last UCC is configured to the serial (UART) Or Ethernet (MII) ,Used for debugging and controlling.

To keen on WLAN technical personning, collect MIMO (enter appearing more more) And OFDM (orthogonality replies demultiplexing frequently) Really worth expecting with WLAN technological 802.11n of future generation all over, but keep people wait a bit anxiously too, several drafts of IEEE are voted not to obtain unanimous opinion. Though there are terminal station products of many 802.11n on the market now, all hit " Pre-N " Impress,in at being compatible been cross unsatisfactory. Taking advantage of trip of Silicon Valley of U.S.A. in June of this year, reporters visited the big factory Broadcom of WLAN chip and specialized in Azimuth that WLAN tests device fabrication, know some new trends.

When does the draft become the standard? Two major camps of WWiSE and TGn Sync of 802.11n compromised each other last August, submitted the motion Draft1.0 of a unified standard to IEEE together. But this does not mean difference has already been solved. The compatibility before and after the draft that WWiSE submits is paid attention to, adopted 20MHz transmission channel, this is the passway where the existing Wi-Fi Apparatus is used at present, can be guaranteed in 5GHz and 2.4GHz frequency band and rearward compatibility and interoperability of the existing WLAN Apparatus under forcing the mode. And the focal point of TGn Sync motion lies in supporting the bandwidth of passway of 40MHz. 40MHz passway is made up of a adjacent 20MHz passway, its speed is more than twice of current 54Mbps data rate, transmit about 125Mbps each time, this is different from maximum of WWiSE draft. Unless the it one take compared with the former to be high at speed, seek to last 640Mbps about speed TGn Sync,looks than under speeds highest of WWiSE is for 540Mbps. But 40MHz is only an alternatives, if adopt 40MHz, TGn Sync is in ad hoc (through ad hoc, the computer cluster does not need AP and make up one WLAN) Under The wireless network application mode, its BSS (Basic Service Set) The compatibility in the same passway and Off-The-Shelf BSS also remains to improve. So letter in March of this year vote (Letter Ballot) It have China Draft1.0 through,agree to 149 ticket, reject and think 171 ticket need to revise still, 32 ticket abstain. According to the introduction of Broadcom family and wireless banking department general manager Michael Hurlston, a key technical matter is that Draft 1.0 does not possess the interoperability with 802.11b/g network, " it is an absolute principle to merge " in this Today for one piece for mortal wound,last one piece committee so work group, responsible for solving this defect. According to arranging, IEEE 6, 9 this year and divide three steps to revise in October. In subsequent June, specially established several ad hoc groups in order to solve the problem of system compatibility in 40MHz passway. Reveal, in September and October, TGn Sync will also continue coordinating the technical matter with the regular meeting through ad hoc group according to Michael, once these problems are solved, it is estimated IEEE will carry on the letter once again to vote in next January, if the vote through rate reaches 75%, the next step is that the sponsor votes (Sponsor Ballot) ,Likewise required 75% of the approval. So the earliest issue time of expectancy of 802.11n is in October of next year.

WLAN of the test instrument with traditional readiness tests including signal channel test, signal intensity, noise density, signal to noise ratio are the most important index in the signal channel tests; The performance test of the network, including basically testing and running and monitoring, the former has AP throughput testing, Ping, site and AP tabulation to analyze etc., the latter has increased real time AP site characteristic generalized analysis on the basis of basically testing, real-time flow analysis, real time network utilization ratio and throughput and nodal isoparameter of transmission rate; In addition there is protocol analysis, failure diagnosis and safeguarding,etc.. And the one that bring 802.11n technology at the characteristic to WLAN is promoted, propose the challenge newly to the test of WLAN either. Azimuth is a special company offering Wi-Fi functional test equipment, company's executive vice president Jeff Abramowtiz shows before 802.11n standard is issued formally, the mutual operability between MIMO products is the important task that WLAN test, especially the products compatibility of Pre-N on the market are not optimistic. And after the standard is issued, besides traditional test item, the test compatible backward of the existing 802.11 a/b/g products will guarantee whether 802.11n products could be accepted by the market rapidly. In addition, from SISO (enter appearing only only) Perform and enter MIMO, WLAN is no longer limited to the transmit data, with the pronunciation, video and data constituent " Triple Play " Bring more QoS questions at the same time. Azimuth calls test plan of its 802.11n draft standardized product " Azimuth MIMO functional test solution " ,On the basis of W-Series platform in the past, characteristic, interoperability, Wi-Fi authorizing, compatibility,etc. (Fig. 1) of allowing the customer to test wireless devices . W-Series adopts the mobile environment of SmartMotion software Engineering analog equipment, testMAC technology fictitious customer end and basic apparatus, combine the actual products of system testing with Real2Real framework. MIMO functional test solution concentrates on MIMO controllable channel dependency (channel dependence) further Test the respect.

Summary: This text introduction adopts the operation amplifier that the electric current of the power can be regulated continuously, realize voltage controlled filter method and principle. Keyword: Operation amplifier; Voltage controlled filter; Digital analog converter

Formate the field in pronunciation and music, often use the voltage controlled filter to envelop and have a facelift the acoustical signal produced. But there are many peripheral devices because with high costs, required, it is relatively complicated to design, the majority this kind of device is not fit for the application of embedded system. Another route to realize voltage controlled filter function is to adopt the operation amplifier that the electric current of the power can be regulated continuously, for instance, the Model LPV531 operation amplifier of the national semi-conductive company of U.S.A.. The power electric current of this amplifier can be regulated within the range of 1uA 400uA continuously. The regulation of the power electric current of the amplifier can go on through one and 10 digital analog converters DAC101S101. In this scheme, the gain bandwidth of the amplifier is a function of the electric current of the power. Fig. 1 has revealed the impact on its gain bandwidth and phase margin of electric current of power of LPV531.

Gaining the relation with wide and power electric current of Fig. 1 LPV531

LPV531 and characteristic of DAC101S101 LPV531 U.S.A. national semiconductor one section programmable and CMOS input and rail to the micropower operation amplifier that rail outputs. Can realize that regulate regulation and power rank of gain bandwidth of LPV531 only through a externally positioned resistance. Can make LPV531 switch over among await the opportune moment and the full power mode through changing the bias voltage on the externally positioned resistance. The power consumption that this operation amplifier works in low frequency 73KHz the most is only 5uA, the power consumption of working in FTOP 4.6MHz is only 425uA. The relatively comparative independence of the input bias voltage, will not be influenced by the fact that the power rank is chosen. LPV531 has adopted CMOS input stage, only has 50fA to input the bias current, common-mode input voltage ranges can be from the negative voltage 1.2V under the positive mains voltage. Meanwhile, LPV531 the intersection of rail and AB to reach rail the intersection of output and steps make their too can offer dynamic range of maximum at low mains voltage. The typical parameter of LPV531 is as follows: *2.7V 5.5V mains voltage; *5uA 425uA electric current of the programmable power continuously; *Input voltage range of common mode - 0.3V 3.8V; *Common-mode rejection ratio 95dB; *The rail reaches the excursion of output voltage of the rail; *1mV input bias voltage; *73KHz 4.6MHz programmable gain bandwidth continuously; *SOT23-6 of the small volume capsulates, is suitable for handheld electronic device and walkie application. Adopt the power electric current of the control amplifier of digital analog converter in this scheme, DAC101S101 is 10 common voltage output type digital analog converters of a full-function of the national semi-conductive company of U.S.A.. It uses the single power to supply power, the voltage range is 2.7V 5.5V, the electric current in 3.6V working voltage is only 175uA. The out amplifier on slice makes it output the rail to the rail excursion. Within the range of specified mains voltage, the clock rate of its serial interface of the strategic hinterland of China can be up to 30MHz. DAC101S101 serial interface compatible SPI, QSPI, MICROWIRE, and DSP standard. The typical parameter of DAC101S101 is as follows: *+0.15 /-0.05LSB DNL; *Export stabilization time: 8uS; *A code error: 3.3mV; *Full errors: -0.06% FS; *Reliable monotonicity; *Low power consumption and power saving mode; *An automatic a voltage output of power up; *Synchronous look-at-me function; *The temperature range of industry: -From 40 ℃ to +105 ℃; *Small-scale TSOT-6 and MSOP-8 capsulate, is suitable for the battery-opwered apparatus.

Controlling the general supply electric current of LPV531 to control the electric current of the pin to carry on dynamic control (Fig. 4) from flowing out ISEL of electric current of the power . The power electric current, with ISEL lineal change, it is 40 times higher than ISEL electric current. Internal relative to negative pole of the power the intersection of 110mV and reference voltage and one the intersection of 11k and ohmic internal resistance determine, when ISEL pin is connected to the negative pole of the power can export the most Heavy current. Bunch enters extra impedance and reduces the output current of ISEL pin between ISEL pin and negative pole of the power. Can calculate the approximate value of the electric current of the power with the following formula:

The curve in Fig. 2 has revealed the relation between REXT and ISEL. In order to realize an electric-wave filter of voltage control, must design ISEL electric current into depending on the voltage is instead of the resistance. Implement method and schematic diagram 3 have revealed that utilizes DAC101S101 and LPV531 to make up the circuit diagram of the voltage controlled filter. Have controlled ISEL pin electric current of LPV531 in the picture with 10 voltage sources that digital analog converter DAC101S101 forms and a resistance voltage divider. The voltage outputted from DAC101S101 is applied to ISEL pin through the resistance voltage divider composed of RSET1 and RSET2. The voltage ratio of the resistance voltage divider sets as and outputs the digital analog converter 0~5V to turn into adding to ISEL pin 0.0~0.11V voltage. In this way the intersection of operation amplifier and LPV531 and the intersection of 3dB and frequency can control applying the intersection of ISEL and voltage at the pin their to.

Fig. 3 when control voltage is nearly 0V utilizes DAC101S101 and LPV531 constituent voltage controlled filter, ISEL electric current confirmed by the parallel resistance of RSET1 and RSET2. When greater than zero in control voltage, the electric current of ISEL is from the south of David of ISEL pin (Thevenin) Equivalent voltage and impedance are fixed. The following formula can use the power electric current of the computing amplifier:

Usually suppose RSET1 is smaller than RSET2 far. In this case, when control voltage is 0V, the maximum value of ISEL electric current is mainly confirmed by the resistance RSET1. In addition, the electric current of ISEL is smaller than 10uA, it is very small compared with source current of the voltage. In given RSET1 and maximum control voltage, but the following formula calculates the resistance quantity of RSET2:

Fig. 3 has revealed LVP531 and is used as the situation of the unit gain dashpot. In this kind of application, in order to meet the signal level of import and export, can connect the operation amplifier into the amplifier mode with oppisite phase or noninverting of certain gain to noise temperature ratio too. Fig. 4 and Fig. 5 are the open loop gain phase diagram when the control voltage is 0.5V and 3.0V respectively.

Fig. 4 0.5V open loop gain phase place of hour

Fig. 5 3V open loop gain phase place of hour