SYNCHRONOUS RECEIVER WITH ANALOG HIGH FREQUENCY SECTION AND DIGITAL LOW FREQUENCY SECTION

摘要

A synchronous receiver comprising a high frequency section realized by analog components, including an input preamplifier followed by two quadrature operated mixers with associated ?/2 phase shifter and a voltage controlled oscillator wherein the high frequency signal is converted by multiplication by means of a phase locked loop directly into the base band and lowpass filters following the mixers for select out interfering mixed products, and a low frequency section following the high frequency section. The receiver is used as a radio or television receiver and the low frequency section is realized by digital components.