Display for frequency received by radio receiver

摘要

A display in a superheterodyne receiver having a local oscillator, adapted for displaying in a digital manner the frequency of a signal being received by the receiver by counting the local oscillation frequency by means of a preset counter wherein the data for the prescribed intermediate frequency or the complement thereof is preset. A reference voltage is generated by means of a variable resistor for correcting the difference between the preset value for the prescribed intermediate frequency and the actual intermediate frequency of the intermediate frequency stage of a receiver as actually manufactured, and a comparison voltage is obtained by digital/analog converting the output of a multiple-bit counter which is stepped responsive to clock pulses. The reference voltage and the comparison voltage are compared and the preset counter is supplied through a gate controlled responsive to the comparison output with the clock pulses of the number associated with the difference between both voltages, whereby the preset value in the preset counter is corrected.