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US 4,283,739 AGranted
Color television receivers
AssigneeTexas Instruments Incorporated
InventorAnthony Martinez
Life of this patent
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AssigneeTexas Instruments Incorporated
InventorAnthony Martinez
Estimating the term…
In a color television receiver, especially for NTSC or PAL color television signals, the intermediate frequency is a phase-lock integral multiple of the sub-carrier frequency. Preferably the intermediate frequency is 4N times the sub-carrier frequency, where N is an integer. The receiver may include a crystal controlled oscillator phase locked to a multiple of the color burst frequency, the oscillations from the oscillator compared with the intermediate frequency and the result of the comparison used to control the frequency of a local oscillator. The oscillations from the crystal controlled oscillator may be used directly for synchronous demodulation of the intermediate frequency signal to give a Y or Y-chroma signal and after addition of a signal of sub-carrier frequency and suitable phase adjustment for synchronous demodulation to give U- and V- signals. Alternatively, the crystal oscillator oscillation and a signal of sub-carrier frequency derived from it may be used separately to give the U- and V- signals.
A receiver for colour television signals of the kind in which colour information is carried as phase dependent modulation of a sub-carrier, the receiver including means for converting a received video signal to an intermediate frequency which is a phase locked integral multiple of the sub-carrier frequency;
A receiver for colour television signals of the kind in which colour information is carried as phased dependent modulation of a sub-carrier signal, the receiver including a local oscillator, means for mixing a received video signal with a signal generated by said local oscillator to produce an intermediate frequency signal having a frequency which is a phase-locked integral multiple of said sub-carrier frequency;
A receiver for colour television signals of the kind in which colour information is carried as phase dependent modulation of a sub-carrier signal, the receiver including a varactor controlled local oscillator, means for mixing a received video signal with a signal generated by said local oscillator to produce an intermediate frequency signal having a frequency which is a phase-locked integral multiple of said sub-carrier frequency;
Dependencies are inferred from the claim text.