FM Video receiver

• US 4,574,308 A
• Filed: 04/20/1984
• Issued: 03/04/1986
• Est. Priority Date: 04/20/1984
• Status: Expired due to Fees

• Current Assignee: Dell-Star Corporation
• Original Assignee: Dell-Star Corporation
• Inventors: Gibson, Galen R., Anstaett, Ralph E. Jr.
• Primary Examiner(s): Chin, Tommy P.
• Application Number:
  US06/602,475
• Time in Patent Office: 683 Days
• Field of Search: 358/188, 358/186, 358/191.1, 358/193.1, 358/195.1, 358/197, 358/198, 358/114, 455/182, 455/192, 455/164, 455/234, 455/142, 455/26, 455/205, 375/1, 375/2.1
• US Class Current: 348/731
• CPC Class Codes: H03J 7/02 Automatic frequency control H03J7/18 takes precedence

Abstract

An FM video receiver includes a UHF tuner coupled to an intermediate frequency amplifier. The output of the IF amplifier is coupled to a video IF amplifier and detector. The latter component is tuned to the video portion of the FM video composite signal, and hence limits and detects the intelligence carried by that signal. A video inverter and video driver process the signal further and applies an amplitude modulated line level video signal at the receiver'"'"'s output. An audio IF amplifier and discriminator are coupled to the output of the video IF amplifier and detector. Since the video IF amplifier essentially passes through the audio portion of the FM video composite signal, the audio IF amplifier limits and detects that audio signal. An automatic gain control network and an automatic frequency control network provide feedback to the tuner.

Claims

1. An FM video receiver supplied with a plurality of frequency modulated (FM) composite video signals by an antenna comprising:

an ultra high frequency tuner having an antenna signal input, an automatic gain control (AGC) signal input and an automatic frequency control (AFC) signal input, said antenna signal input capable of receiving said plurality of FM composite video signals and said tuner including means for selecting one of said plurality of FM composite video signals, said tuner including an amplifying means for amplifying said selected FM composite video signal, said tuner including means for generating an intermediate frequency composite signal carrying the same intelligence as the amplified selected FM composite video signal at a frequency lower than said selected FM composite video signal, said tuner applying said intermediate frequency composite video signal on a corresponding output;

an intermediate frequency amplifier having an input coupled to said output of said tuner, said intermediate frequency amplifier amplifying said intermediate frequency composite signal and applying the amplified intermediate frequency composite signal to a corresponding output;

means for limiting and discriminating said amplified intermediate frequency composite signal, said means for limiting and discriminating tuned to the video portion of said amplified intermediate frequency composite signal and generating an amplitude modulated video signal corresponding to the amplitude of the frequency variation of the video portion of said amplified intermediate frequency composite signal, said amplitude modulated video signal being applied to an output of said means for limiting and discriminating;

a video driver coupled to said output of said means for limiting and discriminating, said video driver amplifying said amplitude modulated video signal to generate a line level video signal at a corresponding output;

an automatic gain control (AGC) means coupled said output of said intermediate frequency amplifier, said AGC means providing a feedback signal to said AGC signal input of said tuner to affect the tuner amplifying means and to stabilize said intermediate frequency composite signal;

an automatic frequency control (AFC) means coupled to said output of said means for limiting and discriminating, said AFC means providing a feedback signal to said AFC signal input of said tuner to affect said means for selecting one of said plurality of FM composite video signals; and

an audio intermediate frequency amplifier coupled to said output of said means for limiting and discriminating, said audio amplifier including means for separating the audio portion from said amplitude modulated video signal, and including an audio limiter and discriminator means, said audio amplifier generating an amplitude modulated audio signal corresponding to the amplitude of the frequency variation of the audio portion of said amplified intermediate frequency composite signal and applying said amplitude modulated audio signal to a corresponding output.

2. An FM video receiver as in claim 1 including an inverter means coupled between said output of said means for limiting and discriminating and both the input of said video driver and the input of said audio intermediate frequency amplifier.