Sampling frequency converter

摘要

A sampling frequency converter of a simplified constitution for use in a format conversion apparatus designed to convert sampled input data (2, 4) of an input sampling frequency into sampled output data of an output sampling frequency. The converter comprises over-sampling means (13) supplied with the sampled input data for increasing the sampling frequency of the sampled input data by a predetermined factor or coefficient to provide over-sampled data; an output data extractor (14, 15) for periodically extracting data from the over-sampled data in response to a timing pulse having the output sampling frequency; and a controller (11) for controlling the phase of the timing pulse to control the phase of the sampled output data. One of the sampled input and output data is a digital color signal such as a luminance signal conforming with the digital composite color signal format, while another of the sampled input and output data is a digital color signal such as a luminance signal conforming with the digital component signal format. And the controller serves to control the phase of the timing pulse in such a manner that the group delay imparted to the digital luminance signal becomes equal to the delay imparted to the digital color signal.