DIGITAL PROCESSING APPARATUS

摘要

An object of the present invention is to reduce spurious generation due to a malfunction of an A/D converter in a device performing digital processing by converting an analog signal high in cyclic characteristics to a digital signal with the A/D converter.

As a concrete solving means, for instance, in a frequency synthesizer of a certain system, the A/D converter is provided on an output side of a voltage controlled oscillator, and its output signal is given to a device performing digital processing to feed back the processing result to the voltage controlled oscillator through D/A conversion. In this case, the noise generated in the band noise generator is added to an input signal of the above-described analog/digital converter. This band noise is a band not affecting the digital signal processing performed by the device.