【正文】 Ceramic filter harmonic surface each accounted for 1%。 Crystal filter accounted for 20%。 The color television receivers of tuning system surface b form filter. In addition, in the defense satellite munication systems has been widely adopted. Surface acoustic filter is electronics and acoustics product of integration of, and can be integrated, so, it all passive filter in the most promising. Various new filter too is various, somewhere, no longer described them. Our country at present the application of various filter proportion Our country39。 Extended working frequency。 Phase array systems beam synthesis and television signals (2) Cystal filter It is to meet with the single technology and developed. In the 1970 s, the integrated production of crystal filter, make it of development have a leap. In the last ten years, crystal filter below to some research: to achieve the best design, besides having the fine choose outside, still have good time domain response。 Generalization of frequency domain filter and related product operation。 Digital munication work and simulation munication work more road between TDM/FDM signal transformation after meet... (3) The multidimensional DF In image processing, earthquake, oil exploration data processing all use multidimensional DF (monly used is 2 d DF), the design of the multidimensional DF, often a d DF optimization design to multidimensional DF direct marketing. For fuzzy and random noise interference 2 d image processing, multidimensional DF also can play a very good effect. In addition, still wave DF, it is easy to realize largescale integrated, facilitate passive and active power filter work digital simulation. Therefore, is attention by people and studied. For DF remains to be subjects of study: coefficient sensitivity, rounding noise and limit cycle, the stability of the multidimensional inverse to filter, all kinds of hardware and software implementation of DF research and so on. In short, DF in digital signal processing technology is very important position in possession, for its research, production and application, etc all is very meaningful. 7, Other new filter In order to adapt to all kinds of need, the emergence of a batch of new filter, presented here has been widely used several types of filters. (1) Electric control programming CCD horizontal filter (FPCCDTF) A chargecoupled device (CCD) fixed weighted transverse filter (TF) in signal processing, the performance and cost all can with digital filter and all kinds of signal processing unit). This filter is mainly used for adaptive filter。 Function is small, can do less than 10 mW. The application of the SCF to audio range application as the main body, the work in 100 kHz frequency within. In signal processing applications are: SPC SCF, analog signal processing, vibration analysis, adaptive filter, music, resonance spectrum, prehensive language integrated device, tone selection, sounds coding, audio analysis, equalizer, modem, phase locked circuit, discrete Fourier transform...... In short, SCF, medical instruments in the meter measuring and data or information processing, and many other areas have broad application prospect. In our country, some 1978 graduate students began to mentor and conducted the research work, and really cause people to pay attention to is 1980 years later. Tsinghua university has made 1983 single chip SCF, chengdu academy of engineering and joint factory, developed a single piece of SCF. Now the key is to use MOS process realize SCF and application of a problem, because users don39。 The function is much, almost all electronic ponents and functions are the SC technology to realize。t pass, and did not cause the attention of people. In 1972, the United States a call Fried scientists published with a switch and capacitance simulation resistance R, said the performance of the SCF depends only on the ratio of capacitance, has nothing to do with capacitance absolute value, so just cause the attention of people. In 1979, some developed countries monolithic SCF has bee a modity (are highly confidential technology). Now SC technology mature. The process to realize the MOS SCF, is recognized as the 80 s work theory and integrated process of a major breakthrough. The current MOS capacitance for a general method to 100 within pF ski