| 摘要 |
<p>A decimation filter arrangement for reducing the sampling frequency of a time-discrete input signal from fi to fu, fu not being a rational portion of fi. For the generation of the required filter coefficients this arrangement comprises clock pulse generators producing first clock pulses ki(.) at a rate fi and second clock pulses au(.) at a rate fu. The arrangement also comprises a coefficients generator in which a deviation component dn is calculated which indicates the ratio between the time interval located between a clock pulse au(.) and the immediately preceding clock ki(.), and the time interval 1/fi between two consecutive clock pulses ki(.). In response to this deviation component this coefficients generator produces N filter coefficients, the mth filter coefficient, m = 0, 1, 2, ....N-1, being equal to an(m) = h [(dn + m) Vo]. Herein the function h(v) represents the impulse response of an FIR-filter, v continuous variable in the interval - ∞ < v < ∞ and Vo a predetermined constant.</p> |
