| 摘要 |
PCT No. PCT/DE88/00020 Sec. 371 Date Aug. 18, 1989 Sec. 102(e) Date Aug. 18, 1989 PCT Filed Jan. 16, 1988 PCT Pub. No. WO88/06381 PCT Pub. Date Aug. 25, 1988.A non-recursive half-band filter having a filter length N includes a receiver unit for receiving a complex input signal having a real component and an imaginary component at a sampling frequency fA, where fA=1/T; and a processing and converting unit for processing and converting the received complex input signal into a complex output signal without changing the sampling frequency of the complex input signal. The processing and converting unit operate according to a function of h(l) and the equation: <IMAGE> and includes a modulating unit that modulates a pulse response h(l), where l=-(N-1)/2 to (N-1)/2 and is an odd filter length. As a result of this structure, it is possible to convert a complex input signal sr1(kT)+jsi1(kT) into a complex output signal s(kT)=sr(k)+jsi(k) by modulating its pulse reponse onto a complex carrier of a frequency equal to 1/4 or 3/4 of the sampling frequency fA, where the null phase of this frequency is an integer multiple of pi /2 and is kept constant.
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