Electronic channel selector

  • Inventors:
  • Assignees: Sony Corp
  • Publication Date: January 16, 1980
  • Publication Number: JP-S555561-A

Abstract

PURPOSE: To realize sure and low cost reception system, by sweeping the reception frequency band and stopping the sweep when it is agreement with the desired frequency. CONSTITUTION: The local oscillation signal of the tuner 11 is divided into 1/256 at the frequency divider and it is fed to the AND gate 13. The output of the reference oscillator 14 is divided into 1/1684 at the frequency divider 15 and it is fed to the AND gate 13 after being delayed. The comparison counter 17 is made of 15-bit, to which the channel frequency code read out from the frequency memory 18 is set. As the output of the AND gate 13, the number of pulses corresponding to the local oscillation frequency is outputted for a given time. From the number set to the comparison counter 17, the number of output pulses of the AND gate 13 is sub- tracted, and the discrimination pulse P 2 is outputted when they are in agreement, P 3 is outputted when the local oscillation frequency is lower, and P 1 is outputted when the local oscillation frequency is higher. Further, the comparison counter is set with the output of the frequency divider 15 so that comparison can be made within in a short time. COPYRIGHT: (C)1980,JPO&Japio

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