Automatically presetting channel selecting system
Radio or television receiver with an automatic station finding arrangement
Solid state television channel selection system
Automatic tuning system
Channel-selecting apparatus for multichannel receivers
AFC circuit Patent #: 4004231
ApplicationNo. 05/784599 filed on 04/04/1977
US Classes:455/182.3, Fine tuning455/186.1, With memory control or programming455/192.3Fine tuning
ExaminersPrimary: Griffin, Robert L.
Assistant: Ng, Jin F.
Attorney, Agent or Firm
International ClassesH03J 7/28 (20060101)
H03J 5/02 (20060101)
H03J 5/00 (20060101)
H03J 7/18 (20060101)
H03J 7/06 (20060101)
H03J 7/02 (20060101)
Foreign Application Priority Data1976-04-05 JP
AbstractIn a channel selecting apparatus for a television receiver having an electronic tuning tuner for changing the receiving frequency in accordance with an analog control signal applied thereto; a memory is provided with a plurality of addresses at which respective digital codes each intended to identify a respective broadcast channel are selectively stored or written in a programming mode of the apparatus, and, in a channel selecting mode of the apparatus, a selected channel identifying digital code is read out of the memory to a digital-to-analog converter which converts the same into a respective analog control signal for tuning the tuner to a receiving frequency. Any deviation of the receiving frequency, as established in response to the analog control signal, from the transmitting frequency for the channel identified by the digital code then being read out of the memory is detected, and in response thereto the digital code being applied to the digital-to-analog converter is modified or changed in the sense for removing the deviation and thereby effecting a fine tuning operation. When, in the channel selecting mode, the detected deviation of the established receiving frequency from the transmitting frequency exceeds a predetermined amount, the resulting modified digital code may be automatically stored or rewritten in the memory in place of the read out digital code resulting in such deviation. The writing of digital codes in the memory in the programming mode and the rewriting of modified digital codes in the memory in the channel selecting mode are permitted only if, at the time of such writing or rewriting, there is being received a broadcast signal with a transmitted frequency corresponding to the receiving frequency established by the digital code to be written or rewritten in the memory.