A digital filter for real, complex and m-times multiplexed signals

摘要

A digital filter of order N according to the present invention consists of a modified filter of order 1 in which N filtercoefficients (an, 0≤n≤N-1) get periodically switched with a clock frequency (fc) that equals to or is higher than the sampling rate (fS) of the filter to set the filter periodically into N internal filter states in each of which an internal output value is calculated before outputting one sample of the output signal (d(1); e(1); y(1)). This filter can filter real signals, IQ-multiplexed signals or m-times multiplexed signals by just providing the number of adders and multiplieres needed to design a filter of order 1 for real signals and one more delay element than needed to design the respective filter. Additionally the transfer function of the inventive filter can be switched very easily by changing the used set of filtercoefficients by just changing control signals. <IMAGE>