Filter for sampling frequency adjustment - has first stage defining blocking region and second stage adjusting transmission region of first stage

摘要

The filter comprises two filter stages, the first of which is non-recursive and the second of which is recursive or non-recursive with a given phase characteristic. The first filter stage is preceded by a switch (K1) used for increasing the sampling frequency by a factor which is a positive whole number greater than 1, by insertion of a number of zeroes between each two sample values of the input signal (S1). The first stage is followed by a second switch (K2) which reduces the supplied signal by a second factor which comprises a second positive whole number.