Autocorrelation coefficient operator having analog circuit element

摘要

The autocorrelation coefficient operator 60 carries out an integration operation to determine the autocorrelation coefficient for audio signal processing or other types of signal processing at high speed with low power consumption. The input signal S is digitized in the A/D converter 30 to the digital signal SP and supplied to a delay unit 40, which delays and holds the digital signal SP sequentially. A sample holder 45 also samples and holds the analog signal S in synchronization with the delay unit 40. When the number of sampled values held by the sample holder 45 reaches a predetermined value, the sample holder 45 outputs the sampled values at the same time in accordance with a sampling clock signal CK which is supplied by a clock signal generator 35. Delayed values held in the delay unit 40 are shifted and output sequentially in accordance with a shift clock signal SCK, the frequency of which is higher than that of the sampling clock signal CK. A weighted addition circuit 50 integrates these sampled values and the delayed values to calculate the autocorrelation coefficient R.