| 摘要 |
PURPOSE:To make a higher harmonic spectrum due to the nonlinearity of a D/A converting circuit into a white noise with simple circuit constitution by providing an adding circuit which adds random data of frequency higher than the frequency band of an acoustic signal to digital data obtained by oversampling the acoustic signal. CONSTITUTION:The adding circuit 1 is supplied with digital data (a) on a signal component in a frequency band of about <=20 KHz within a Nyquist area. Random data from a random data generating circuit 2, on the other hand, is supplied to a HPF 3, which passes and supplies only data C in the high frequency range of the Nyquist area to the circuit 1. Data on a frequency spectrum fS generated by the circuit 1 is therefore supplied to the D/A converting circuit 4 and converted into an analog signal. This signal is supplied to a LPF 6 through a deglicher 5.
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