U.S. Philips Corporation

Gerard Verkroost

Hans-Jurgen Butterweck

Adrianus C Van Meer

A recursive digital filter includes a first circuit 1 including a cascade arrangement of a magnitude truncation quantizing arrangement and an adder 6, 8. The first circuit has an output 5, and also inputs 3 and 4, output 5 being connected to the input 3 via a second circuit 10 and to the input 4 via a third circuit 11. Both last-mentioned circuits are formed by a cascade arrangement of an auxiliary circuit 12 and 14, respectively, and a multiplier arrangement 13 and 15, respectively. The auxiliary circuit 12 has a transfer function H.sub.1 (z)=p/(z-1) and the auxiliary circuit 14 has a transfer function H.sub.2 (z)=q/(z+1), wherein p and q represent constants.

Recursive digital filter

A digital signal processing arrangement including a wave digital filter having quantizing means for limiting the signal waves present to a predetermined word length by means of controlled rounding. 'Controlled rounding' means that a limit-cycle-free output signal is obtained when a constant input signal is present. If the outgoing signal waves from the N-port adaptor are equal to b.sub.o (j,k), and the signal waves applied to the adaptor are equal to a(j,k), b(j,k) is equal the desired and quantized value of b.sub.o (j,k), where j represents the number of the port, then the process of controlled rounding quantizes b.sub.o (j,k) in such a way that ##EQU1## Here the c(i,j) represent constant coefficients, and r the number of independent information signal waves.

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Mierlo, Netherlands

Gerard Verkroost