Circuit for converting hdtv signals into conventional tv signals with

Abstract

A high definition television signal conversion circuit using a side cut mode or a letter box mode. The conversion circuit using the side cut mode comprises an A/D converter for converting a high definition television signal into a digital signal at a first sampling frequency, a line filtering circuit for performing a vertical interpolation of the digital signal from the A/D converter, a line decimation circuit for performing a vertical decimation of output data from the line filtering circuit, a horizontal filtering circuit for performing a horizontal interpolation of output data from the line decimation circuit, a horizontal decimation circuit for performing a horizontal decimation of output data from the horizontal filtering circuit, a memory device for storing output data from the horizontal decimation circuit in response to a write clock and outputting the stored data in response to a read clock, the read clock being determined according to a scanning mode, a D/A converter for converting output data from the memory device into an analog signal at a second sampling frequency, the second sampling frequency being determined according to the scanning mode, and a switch being turned on/off according to the scanning mode to control the data output from the memory device.