| 摘要 |
A control circuit for controlling selected functions in a signal receiver, such as a television receiver, in response either to remotely generated control signals of different selected frequencies or to manual controls which are provided on the signal receiver. The control circuit comprises an integrated circuit having a first input for receiving the remotely generated control signals. A frequency discriminator is included in the integrated circuit to detect the frequency of a signal applied thereto and to produce corresponding function control signals. A variable oscillator, also included in the integrated circuit, selectively generates local control signals of substantially the same different selected frequencies as the remotely generated control signals. A mixing circuit supplies the received remotely generated control signals or the local control signals to the frequency discriminator. A frequency control circuit, exernal of the integrated circuit and coupled to the manual controls, produces a variable frequency-control signal as a function of the operation of the manual controls. A second input provided in the integrated circuit connects the frequency control circuit to the variable oscillator, whereby the frequency of the local control signal generated by the variable oscillator is determined by the frequency-control signal produced by the frequency control circuit connected thereto. |
