| 摘要 |
An apparatus for estimating the frequency (fa1) and/or the phase ((phiPa1) of a digital input signal (x(i)) comprises: a phase recording device (3) which determines phase values (Ca1(i)) of the input signal (x(i)); a first filter (4), which adds up the phase values (Ca1(i)) over a predetermined summation length N/B, which is a predetermined fraction 1/B of an observation length of N phase values (Ca1(i)), to form added-up phase values (Sa1(i)), and which reduces the sampling rate of the added-up phase values (Sa1(i)) by a factor N/B in comparison with the sampling rate (fa2) of the phase values (Ca1(i)), a second filter (8) which delays the added-up phase values (Sa1(i)) in a chain of at least B-1 delay elements (15, 16; 26-30), each delaying the added-up phase values (Sa1(i)) by one sampling period of the reduced sampling rate (fa2.B/N), and adds or subtracts the differently-delayed added-up phase values (Sa1(i)), to create a resulting pulse response (hf) of the frequency such that the resulting pulse response (hf) of the frequency is constant positive in a first interval (40), is zero in a second interval (41) and is constant negative in a third interval (42), and/or they are added to create a resulting pulse response (hphi) of the phase so that the resulting pulse response (hphi) of the phase is constant in at least a middle interval (43) and otherwise is zero.
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