Indoor unit of receiver for broadcasting satellite

Claim 1

An indoor unit of a receiver which receives radio waves transmitted from a broadcasting satellite and group-converts the received radio waves into a first intermediate frequency signal which is then fed to said indoor unit for conversion into a second intermediate frequency signal; the indoor unit having a single superheterodyne structure comprising: a mixer for converting the first IF signal into the second IF signal; a first VCO coupled to and driving the mixer; an IF amplifier for coupling the second IF signal out from the mixer; a PLL demodulator having a phase comparator, a loop filter and a second VCO, wherein a first portion of the VCO output is coupled to the phase comparator, and the input of said PLL demodulator is coupled to the IF amplifier output; and an AFC circuit coupled to a second portion of the output of said second VCO and generating a control signal for controlling the frequency of the first VCO; wherein the frequency of said second IF signal is selected sufficiently high so that an image frequency thereof is not included within the receiving range of the IF amplifier and a prescaler for dividing the second portion of the output of said second VCO, the prescaler being interposed between the output of the second VCO and the AFC circuit and supplying a divided-down signal to said AFC circuit.