Integrated single and dual television tuner having improved fine tuning
AssigneeATI Technologies, Inc.
InventorFeliks Dujmenovic
Life of this patent
Estimating the term…
Abstract
Improved television tuning circuits are disclosed. An example tuning circuit includes a fraction-N frequency synthesizer facilitating fine tuning. This tuning circuit may be formed using relatively few independent oscillators. The tuning circuit lends itself to the formation of an tuning circuit on an integrated circuit substrate. As well, this tuning circuit may be used to form a dual tuner tuning circuit integrated on a single integrated circuit substrate.
Claims15
A dual television tuner tuning circuit formed on an integrated circuit substrate, comprising:
- a first dual conversion television tuner operable to tune a first television channel in a received radio frequency signal;
- a second dual conversion television tuner operable to tune a second television channel independently of said first television channel in said received radio frequency signal;
- first and second frequency synthesizers associated with said first tuner for tuning said first channel;
- third and fourth frequency synthesizers associated with said second tuner for tuning said second channel;
- wherein one of said first and second synthesizers comprises a fractional-N synthesizer, comprising a single controllable oscillator to fine tune said first dual conversion tuner, and one of said third and fourth frequency synthesizers comprises a fractional-N synthesizer comprising a single controllable oscillator to fine tune said second dual conversion tuner.
A dual conversion television tuning circuit for tuning a television channel in a received radio frequency signal, comprising:
- first and second frequency synthesizers;
- a first mixer, to mix said channel, with a first mixing signal from said first frequency synthesizer and thereby frequency shift said channel to a first frequency;
- a bandpass filter coupling an output of said first mixer to an input of a second mixer;
- said second mixer to mix said channel with a second mixing signal from said second frequency synthesizer and thereby translate said channel to an intermediate frequency;
- wherein at least one of said first and second synthesizer is formed using a fractional-N frequency synthesizer, comprising a single controllable oscillator, to allow fine tuning of said tuning circuit.
A method of tuning two co-located television tuners, comprising:
- synthesizing a first mixing signal using a first fractional-N frequency synthesiser having a single controllable oscillator to provide a first fine tuning signal therefrom;
- synthesizing a second mixing signal using a second fractional-N frequency synthesiser having a single controllable oscillator to provide a second fine tuning signal therefrom;
- providing said first and second mixing signals to first and second mixers, respectively, thereby fine tuning said two tuners.
A dual television tuner tuning circuit formed on an integrated circuit substrate, comprising:
- a first dual conversion television tuner operable to tune a first television channel in a received radio frequency signal;
- means for providing a synthesized signal to said first tuner to tune a first channel to an intermediate frequency;
- means for providing a synthesized signal from a single controllable oscillator to fine tune said first channel to a first output intermediate frequency;
- a second dual conversion television tuner operable to tune a second television channel in a received radio frequency signal;
- means for providing a synthesized signal to said second tuner to tune said second channel to an intermediate frequency;
- means for providing a synthesized signal from a single controllable oscillator to fine tune said second channel to a second output intermediate frequency.
Dependencies are inferred from the claim text.