Tuning system for a color television receiver having a varactor tuner

摘要

An improved tuning system for a color television receiver embodying a varactor tuner having a controller functioning as a potentiometer to provide a preselected tuning voltage for channel selection. The system includes a tuning voltage supply having a low impedance drive which is serially connected at its output with the controller. The voltage supply applies a preselected source voltage to the controller which is substantially independent of changes in the resistive value of the controller. The tuning voltage supply is combined with automatic fine tuning correction circuitry connected between the automatic fine tuning system and the varactor tuner. The automatic fine tuning correction circuitry applies a correction voltage to the varactor tuner for temperature compensation, fine tuning errors of 500 KHZ or less, etc.