Importance

Loading Importance Indicators...

Abstract

A digital signal communication system includes a transmission circuit or a receiving circuit for digitally transmitting two types of signals by orthogonal modulation. The transmission circuit includes an orthogonal modulator and a nonrecursive digital low-pass filter having the same frequency characteristic as a predetermined frequency characteristic of the output signal of the orthogonal modulator. The receiving circuit includes an orthogonal demodulator and a nonrecursive digital low-pass filter having the same frequency characteristic as a predetermined frequency characteristic of the output signal of the orthogonal demodulator. The total number of taps required for determining the frequency characteristic of the nonrecursive digital low-pass filter is set to H, and the series of tap coefficients is set as C.sub.1, C.sub.2, C.sub.3, . . . , C.sub.H, where H is an arbitrary positive integer of not less than 2. The nonrecursive digital low-pass filters include a first low-pass filter for filtering one of the two types of signal and a second low-pass filter for filtering the other type of the signal. The first low-pass filter has taps about one half of H including a tap coefficient series C.sub.1, C.sub.3, C.sub.5, . . . , C.sub.ODD, and the second low-pass filter has taps about one half of H including a tap coefficient series C.sub.2, C.sub.4, C.sub.6, . . . , C.sub.EVEN.

Loading the Abstract Image...

First Claim