Modulator system

Claim 2

A modulator system comprising: means for providing a video information signal including synchronizing pulse components and means for providing an audio information signal; a frequency modulator having an input terminal and an output terminal, said frequency modulator input terminal coupled to said audio information signal providing means such that a frequency modulated audio information signal is developed at said frequency modulator output terminal; means for providing a radio frequency carrier signal; a balanced amplitude modulator coupled to said radio frequency carrier signal providing means and having an input terminal adapted to be energized by modulating signal information and an output terminal adapted to provide a radio frequency carrier signal amplitude modulated by said modulating signal information; means coupled to said balanced amplitude modulator for causing a maXimum amplitude carrier signal to be developed at said modulator output terminal when no modulating signal information is applied to said input terminal; means coupled between said amplitude modulator input terminal and both said frequency modulator output terminal and said video information signal providing means for applying said frequency modulated audio information signal and said video information signal as modulating signal information to the input terminal of said balanced amplitude modulator; and the amplitude of said carrier signal at said output terminal varying from said maximum amplitude and being modulated by said modulating signal information with said carrier signal maximum amplitude developed only over that period of time when said modulating signal information includes synchronizing pulse components associated with said video signal.

Claim 3

A modulator system as defined in claim 1 wherein the frequency of said radio frequency carrier signal is selected to be a frequency to which a television receiver tuner is tunable.

Claim 4

A modulator system as defined in claim 2 wherein said frequency modulated audio information signals have a center frequency of 4.5 MHz.

Claim 5

A modulator system as defined in claim 3 wherein said video information signals contain luminance and chrominance information.

Claim 6

In a video playback system of the type wherein a composite television signal recorded on a record medium is detected and processed to provide both an audio information signal and a video information signal for use in a television receiver having a tuner coupled to an antenna terminal, a modulator system comprising: means for providing a radio frequency carrier signal selected to be of a frequency to which said television receiver is tunable; a balanced amplitude modulator coupled to said radio frequency carrier signal providing means and having an input terminal and output terminal; a frequency modulator having an input terminal and an output terminal; first coupling means connected between said frequency modulator input terminal and said video playback system for coupling said audio information signal to said frequency modulator input terminal, said frequency modulator operable to develop at said frequency modulator output terminal a 4.5 MHz signal frequency modulated by said audio information signal; second coupling means connected between said balanced amplitude modulator input terminal and both said frequency modulator output terminal and said video playback system for coupling said frequency modulated 4.5 MHz signal and said video information signal to said balanced amplitude modulator input terminal, said balanced amplitude modulator operable to develop a carrier signal amplitude modulated by said frequency modulated 4.5 MHz signal and said video information signal at said balanced modulator output terminal; and third coupling means connected between said balanced amplitude modulator output terminal and said television receiver antenna terminal for coupling said amplitude modulated carrier signal to said television receiver antenna terminal.

Claim 7

In a video playback system of the type wherein a composite television signal recorded on a record medium is detected and processed to provide both an audio information signal and a video information signal for use in a television receiver having a tuner coupled to an antenna terminal, a modulator system comprising: means for providing a radio frequency carrier signal selected to be of a frequency to which said television receiver is tunable; a balanced amplitude modulator coupled to said radio frequency carrier signal providing means and having an input terminal and output terminal; a frequency modulator having an input terminal and an output terminal; first coupling means connected between said frequency modulator input terminal and said video playback system for coupling said audio information signal to said frequency modulator input terminal, said frequency modulator operable to develop at said frequency modulator output terminal a 4.5 MHz signal frequency modulated by said audio information signal; second coupling means connected between said balanced amplitude modulator input terminal and both said frequency modulator output terminal and said video playback system for coupling said frequency modulated 4.5 MHz signal and said video information signal to said balanced amplitude modulator input terminal, said balanced amplitude modulator operable to develop a carrier signal amplitude modulated by said frequency modulated 4.5 MHz signal and said video information signal at said balanced modulator output terminal; and third coupling means connected between said balanced amplitude modulator output terminal and said television receiver antenna terminal for coupling said amplitude modulated carrier signal to said television receiver antenna terminal.

Claim 8

A modulator system as defined in claim 5 wheerin said video information signal includes synchronizing pulse components, and further including means coupled to said balanced amplitude modulator for causing a maximum amplitude carrier signal to be developed at said balanced amplitude modulator output terminal when no modulating signal information is applied to said balanced amplitude modulator input terminal so that the amplitude of said carrier signal at said amplitude modulator output terminal varies from said maximum amplitude in accordance with said modulating signal information and said maximum amplitude is developed only over that period of time when said modulating signal information includes synchronizing pulse components associated with said video information signal.

Claim 9

A modulator system as defined in claim 6 wherein said balanced mOdulator includes a plurality of balanced reactances, and wherein said maximum amplitude carrier signal causing means establishes an unbalanced condition between said reactances, and said frequency modulated 4.5 MHz signal and said video information signal coupled to said balanced amplitude modulator input terminal oppose said unbalanced condition and tend to re-establish a balanced condition as the amplitude of said coupled signals increases.

Claim 10

A modulator system as defined in claim 7 wherein said plurality of reactances are a plurality of diodes and said means coupled to said balanced amplitude modulator establishes a DC offset condition.

Claim 11

A modulator system as defined in claim 8 wherein said video information signal contains luminance and chrominance information.