【正文】 畢業(yè)設計（論文）外文文獻翻譯 院 系： 電子與電氣工程系 年級專業(yè)： 姓 名： 學 號： 附 件： digital filter design 指導老師評語： 所翻譯的外文參考文獻與畢業(yè)論文選題一致，翻譯較為準確，撰寫格式規(guī)范，裝訂正確。 指導教師簽名： 年 月 日 外文文獻： digital filter design Abstract： With the information age and the advent of the digital world, digital signal processing has bee one of today39。s most important disciplines and door technology. Digital signal processing in munications, voice, images, automatic control, radar, military, aerospace, medical and household appliances, and many other fields widely applied. In the digital signal processing applications, the digital filter is important and has been widely applied. Keyword： SCM。 Proteus, C language。 Digital filter figures Unit on : Analog and digital filters In signal processing, the function of a filter is to remove unwanted parts of the signal, such as random noise, or to extract useful parts of the signal, such as the ponents lying within a certain frequency range. The following block diagram illustrates the basic idea. There are two main kinds of filter, analog and digital. They are quite different in their physical makeup and in how they work. An analog filter uses analog electronic circuits made up from ponents such as resistors, capacitors and op amps to produce the required filtering effect. Such filter circuits are widely used in such applications as noise reduction, video signal enhancement, graphic equalisers in hifi systems, and many other areas. There are wellestablished standard techniques for designing an analog filter circuit for a given requirement. At all stages, the signal being filtered is an electrical voltage or current which is the direct analogue of the physical quantity (. a sound or video signal or transducer output) involved. A digital filter uses a digital processor to perform numerical calculations on sampled values of the signal. The processor may be a generalpurpose puter such as a PC, or a specialised DSP (Digital Signal Processor) chip. The analog input signal must first be sampled and digitised using an ADC (analog to digital converter). The resulting binary numbers, representing successive sampled values of the input signal, are transferred to the processor, which carries out numerical calculations on them. These calculations typically involve multiplying the input values by constants and adding the products together. If necessary, the results of these calculations, which now represent sampled values of the filtered signal, are output through a DAC (digital to analog converter) to convert the signal back to analog form. Note that in a digital filter, the signal is represented by a sequence of numbers, rather than a voltage or current. The following diagram shows the basic setup of such a system. Unit refers to the input signals used to filter hardware or software. If the filter input, output signals are separated, they are bound to respond to the impact of the Unit is separated, such as digital filters filter definition. Digital filter function, which was to import sequences X transformation into export operations through a series Y. According to figures filter function 24hour live response characteristics, digital filters can be divided into two, namely, unlimited long live long live the corresponding IIR filter and the limited response to FIR filters. IIR filters have the advantage of the digital filter design can use simulation results, and simulation filter design of a large number of tables may facilitate simple. It is the shortings of the nonlinear phase。 Linear phase if required, will use the entire work phasecorrection. Image processing and transmission of data collection is required with linear phase filters identity. And FIR linear phase digital filter to achieve, but an arbitrary margin characteristics. Impact from the digital filter response of the units can be divided into two broad categories : the impact of the limited response (FIR) filters, and unlimited number of shocks to (IIR) digital filters. FIR filters can be strictly linear phase, but because the system FIR filter function extremity fixed at the original point, it can only use the higher number of bands to achieve their high selectivity for the same filter design indicators FIR filter called band than a few highIIR 510 times, the cost is higher, Signal delay is also larger. But if the same linear phase, IIR filters must be workwide calibration phase, the same section also increase the number of filters and work plexity. FIR filters can be used to achieve nonDigui way, not in a limited precision of a shock, and into the homes and quantitative factors of uncertainty arising from the impact of errors than IIR filter small number, and FIR filter can be used FFT algorithms, the putational speed. But unlike IIR filter can filter through the simulation results, there is no readymade formula FIR filter must use puteraided design software (such as MATLAB) to calculate. So, a broader application of FIR filters, and IIR filters are not very strict requirements on occasions. Unit from subfunctions can be divided into the following four categories : (1) Lowfilter (LPF)。 (2) highfilter (HPF)。 (3) beltfilter (BPF)。 (4) to prevent filter (BSF). The following chart dotted line for the ideals of the filter frequency characteristics : MATLAB introduced MATLAB is a matrix laboratory (Matrix Laboratory) is intended. In addition to an excellent value calculation capability, it also provides professional symbols terms, word processing, visualization modeling, simulation and realtime control functions. MATLAB as the world39。s top mathematical software applications, with a strong engineering puti