公开(公告)号：US4125866A

公开(公告)日：1978-11-14

申请号：US807168

申请日：1977-06-16

申请人： Hendrik A. VAN Essen ,  Petrus J. VAN Gerwen

发明人： Hendrik A. VAN Essen ,  Petrus J. VAN Gerwen

IPC分类号： H03H17/06 ,  G06F15/34

CPC分类号： H03H17/06

摘要： A non-recursive discrete filter for simultaneously realizing for example two band-pass filter characteristics starting from a given lowpass transfer characteristic, wherein one bandpass filter has an in-phase transfer characteristic and the other filter the quadrature transfer characteristic of this in-phase filter. The central frequency of these filters is f.sub.o and the output sampling frequency is f.sub.s = 8f.sub.o. This discrete filter comprises multiplying means in which input signal samples x(n) are modified by an associated filter coefficient a(i) for generating modified input signal samples z(n,i) = a(i)x(n-i). The coefficients a(i) are the same for both transfer characteristics and are given by: ##EQU1## WHEREIN H.sub.1 (I) REPRESENTS THE DISCRETE IMPULSE RESPONSE OF THE LOWPASS FILTER.To realize the in-phase transfer characteristic the samples z(n,i) are thereafter multiplied by a factor sgn[cos (.pi.i/4)] and the products thus obtained are accumulated.This results in the output signal sample ##EQU2## To realize the quadrature transfer characteristic the samples z(n,i) are thereafter multiplied by a factor sgn[sin(.pi.i/4)] and the products thus obtained are accumulated. This results in the output signal sample ##EQU3##

摘要翻译： 一种非递归离散滤波器，用于从给定的低通传输特性开始同时实现两个带通滤波器特性，其中一个带通滤波器具有同相传输特性，另一个滤波器具有该同相滤波器的正交传输特性 。 这些滤波器的中心频率为fo，输出采样频率为fs = 8fo。 该离散滤波器包括乘法装置，其中输入信号采样x（n）由用于产生经修改的输入信号样本z（n，i）= a（i）x（n-1））的相关联的滤波器系数a（i）修改。 对于两个传送特性，系数a（i）相同，并由下式给出：对于cos（pi i / 4），a（i）= h 1（i）| cos（pi i / 4） = 1（i）| sin（pi i / 4）|对于cos（pi i / 4）= 0 WHEREIN H1（I）表示低通滤波器的离散冲击响应。