In radio receiving and dispatching DA transformation.docx

1、In radio receiving and dispatching DA transformationIn radio receiving and dispatching D/A transformationIts basic thought is to constructs aOpen the programmable hardware in type terrace in general usely, pass to add to carry homologous software mold piece to realize homologous lead-inBroadcasting

2、station function.On the in general use terrace, as long as change the relevant software, can complete conveniently to the broadcasting station Can of modification and expand, but need not design to construct the hardware electric circuit system afresh.Such radio station permits very muchRealizes eas

3、ily to permit with current or future and various broadcasting station concurrently, utmost satisfy the request that mutual communication with each other connect.Can save time of development for the broadcasting station of large quantity to renew with develop the budget at the same time.This first at

4、 correspond by letter( particularly is atMove the correspondence) realm need having got urgently with the applied foreground of the amplitude. The basic equipments of the wireless correspondence inside is a radio station.20 centuries 7 80ses beginning, along with numberThe word handles technical dev

5、elopment with maturity, traditional radio station, solve from the control, letter source letter a plait of the systemCode, hardware technique etc. realized in many ways and all from imitate the numeral transition.Arithmetic figure radio station is from whole machineThe construction is all with the f

6、unction than emulation radio station contain substantial advance.Someone still puts forward the total amount word receives and dispatchThe concept of the letter machine, is to act for with the arithmetic figure electric circuit mostly the broadcasting station inside, will imitate the signal through

7、the A/ DAdopting the kind arithmetic figure turns, the arithmetic figure of application handles the technique proceeds to handle to the signal, completing the information receive with shoot, This is the lead-in to deliver the equipments in essence a leap.But the arithmetic figure radio station still

8、 exsits shortage, its Can of realizes to have the very strong dependence to the hardware, the particular broadcasting station is only and can use in particular correspondence system, Moreover, expand along with the correspondence business, the new old broadcasting station permits concurrently very d

9、ifficult.Therefore, face the lead-in the correspondenceVarious the type of systems of the system inside, the target that current radio station cant satisfy future individual the correspondence. The software wireless emerges with the tide of the times, providing a way of thinking for resolving this p

10、roblem.It regard software as principle,But not depend on the hardware characteristic directly, realize the system open the sex structurally, completely programmable, have biggestOf vivid with adapt to the ability.The function of the wireless be defined by software, only changes to apply in the in ge

11、neral use platformLast software, can adjust with the work frequency that changes broadcasting station, make the intermediation method, plait the solution the code method,The velocity pass type of the business category, data, encrypt the mode and connect into control agreement etc.Acquire any a kind

12、ofCorrespondence system, relaxed realize every kind of correspondence is standard to permit concurrently.This is the lead-in technique to transfer the arithmetic figure from the emulationEmpress of again once revolution strides over.2 technical characteristics in wireless in software. The software w

13、ireless is a terrace to establish at an open the sex, mold piece to turn top of, its wants to realize every kind ofThe function can pass the software plait distance to realize, it of basic constitute such as the figure 1. 1 show.This will beg the breadth takesThe A/ D is possibly with the D/ the tra

14、nsformation of AN of near radio frequency head.The mold few transformation( A/ D) is an one of the key to realizes software wireless techniques.This text introduced the concept of the software wireless first, then emphasized to analyze the A/ D transformation machine various techniques index sign, c

15、ombine combinative solid a method for, detailedly discussing A/ D adopting kind.1 lead the speech The all and beautiful long range system( NationalTelesystems Conference) meeting is last in 1992 May, the company of Mitre scientist Joe Mitola at together IEEE a member conversation, put forward the co

16、ncept of the software wireless first.He thinks:Software wireless system according to hardware terrace, its A/ the transformation of D should as much as ever close to antenna, but correspond by letter possibly many lead-ins to function to realize with the software.The general construction of the soft

17、ware wireless system,such as figure,1 show. Compare with the traditional wireless system, the software wireless carry to radio frequency to take side to the best the A/ the transformation of D, but will inside ( even radio frequency ) all proceedings arithmetic figure wills turn to handle later on,

18、the advantage that he bring is a radio frequency head small scaled turning, the correspondence function software turns, the system hardware is in general use to turn.The first software wireless is an American solider to is a broadband to take for the sake of solution every kind of for use by the mil

19、itary broadcasting station a characteristics for of mutual communication problem, software wireless broadcasting station, many the segment of s, make way more, code way more, much negotiate, small physical volume, easy to grade creep etc.For this, the total office( ARPA) in plan in research in Minis

20、try of National Defense high class in the United States put forward the Speakeasy plans, should plan the target of the first stage is to researches to manufacture development a many molds broadcasting station( MBMMR), the Speakeasy I is first the period development model( ADM) to have done to play t

21、o show to a little bit governmental representative in 1994 August, he play to show totally below a few contentses: (1) difference with the standard broadcasting station mutual communication of 4 kinds of government materials, among them include the military tactics radio station Have Quick, HFMODEM(

22、 MIL- As STD-188-110s), automatic network establish the ALE( As MS-188-141) to carry the wireless system SINCGARS with genuine in single letter with the machine; (2) jump the net top to shoot at the same time with the SINCGARS at the Have Quick, realize at the same time with these two kinds of broad

23、casting stations correspondence; (3) conduct and actions net bridge/ pass conjunction Have Quick with the net of SINCGARS, make 2 the customer on the nets information delivered transparently; (4) on 2 Speakeasies broadcasting station, changes at the same time after the SINCGARS a form parameter can

24、still mutual communication, showed the programmable ability in a form. This time play the contents that show include speech, data and calculators produce, and pass the HFMODEM deliver of see the picture of .Should plan in 1999 the development of the second stage Speakeasy II complete, he increased t

25、he network function of the software wireless, expandeding the broadcasting station of MBMMR can concurrently a form that permit, include GPS, WNA( the lead-in network connects into), beehive telephone etc. Because of past compare advantage in system in wireless in software, he was paid attention to

26、by more and more realms.In 1996, was started by the United States, a little bit Japanese company to establish the forum of MMITS, aim is in study develop software lead-in too prepare software wireless technique apply to three generations move correspond by letter system IMT-2000, and have started AC

27、TS( AdvancedCommunication Technologies& Services) etc. plan. Realizing the software wireless includes below a few keys technique:The breadth takes the antenna to take with the breadth the radio frequency mold piece, breadth takes A/ the transformation of D, super-speed DSP machine an etc.Among them

28、A/ the D transformation machine function quality affects directly to extent that realizes software wireless with the function index sign of the system, for this reason A/ it is to proceed ? that D transformation machine choose to useA function for/ D transformation machine parameter2.1 adopt the kin

29、d velocity with distinguish the rate The kind velocity that adopt the velocity points the mold few transformation, but distinguish the ratio that rate mean transformation exportation arithmetic figure data with the number.This 2 parameters is very important, because adopt the kind velocity higherly

30、with distinguish the rate to should the high letter compares to input to take the breadth with the wide signal.In the last few years, A/ the D machine a function increases very quickly, the single is to adopts the kind velocity about turn over every two years a times.A few As/ the D machine piece ad

31、opts the kind velocity with distinguish the rate,such as table,1 show. 2.2 Letter ratio The letter ratio SNR( Signalto Noise Ratio) points the signal the all square a value and other frequency weight( do not include harmonious wave in direct current) all square a specific value for of specific value

32、, letter ratio SINAD( Signal to Noise andDistortion) pointing signal all square a value and all square root in weight( include a the wave of but do not include the direct current) in other frequency, so SINAD ratio SNR ?If consider only the deal turns the voice of , the letter ratio SNR can mean for

33、: Among them:The B is an A/ D conversion the machine distinguishes the rate, the fS is for adopting the kind velocity, fmax for tallest frequency that input the signal. From type(1) therefore, be the fS adopt the kind velocity same as with( Nyquist) velocity, namely fS=2 fmaxes, distinguish the rate each increase 1 bit, the le