SAMPLING RATE CONVERTER

摘要

A position coordinate difference computing unit (5a to 5c) calculates position coordinate differences between position coordinates of the output digital signals and position coordinates of the input digital signals adjacent to the position coordinates. An FIR coefficient memory (13a to 13c) stores FIR coefficients of an FIR-LPF and outputs FIR coefficients corresponding to position coordinate differences between a fixed number of the output digital signals adjacent to the position coordinates of the output digital signals and the output digital signals. A control unit (11) supplies a group of the FIR coefficients and a group of the input digital signals corresponding to the respective position coordinate differences to the parallel FIR calculator (4) in predetermined order when the position coordinate differences corresponding to two or more different output digital signals are concurrently computed. The parallel FIR calculator (4) performs an FIR-LPF interpolating calculation by using those to obtain the output digital signals.

主权项

1. A sampling rate converter converting input digital signals sampled at an input sampling rate into a plurality (a) of output digital signals Yki (i=1, 2, . . . , a) each sampled at output sampling rates different from each other, comprising:
a position coordinate difference computing unit calculating position coordinate differences Dki between position coordinates Tki of the plurality of output digital signals Yki and position coordinates of the input digital signals adjacent to the position coordinates Tki; an FIR coefficient memory storing FIR coefficients F(z) of a finite impulse response low pass filter (FIR-LPF) at a position coordinate z, and outputting FIR coefficients F(Tki−Zki(q)) corresponding to position coordinate differences (Tki−Zki(q)) (q=1, 2, . . . , p) when the position coordinate differences Dki are input, wherein the FIR-LPF has a characteristic of blocking frequency components which are ½ or more of the output sampling rate and Zki (q) represent position coordinates of a fixed number (p) of input digital signals Xki (q) present in the vicinity of a periphery of the position coordinates Tki of the output digital signals Yki; an FIR calculator calculating Yki=F(Tki−Zki(1))*Xki(1)+F(Tki−Zki (2))*Xki(2)+ . . . +F(Tki−Zki (p))*Xki (p) to obtain the plurality of output digital signals Yki; and a control unit supplying a group of the FIR coefficients and a group of the input digital signals corresponding to the respective position coordinate differences, to the FIR calculator in predetermined order when the position coordinate differences corresponding to two or more different output digital signals are concurrently computed.