Integrated single and dual television tuner having improved fine tuning
AssigneeATI Technologies, Inc.
InventorFeliks Dujmenovic
Life of this patent
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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.
Claims19
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;
- and
- third and fourth frequency synthesizers associated with said second tuner for tuning said second channel.
A computing device comprising the tuning circuit of claim 1.
A tuning module for use in an electronic appliance, said tuning module comprising the tuning circuit of claim 1.
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.
The tuning circuit of claim 13, wherein said second mixer comprises and image rejection mixer.
The tuning circuit of claim 13, wherein said fractional-N synthesizer comprises a voltage controlled oscillator providing an output;
- a two modulus scaler having two states and operable to frequency divide said output by a first value in its first state, and by a second value in its second state to provide a frequency scaled output;
- a phase detector to detect a phase difference between a periodic reference signal and said frequency scaled output, and having an output controlling said voltage controlled oscillator;
- an accumulator in communication with said two modulus scaler, for changing the state of said two modulus scaler after a plurality of periods of said reference signal.
A method of tuning a television tuner, comprising:
- synthesizing a mixing signal using a fractional-N frequency synthesiser;
- providing said mixing signal to a mixer thereby fine tuning said tuner.
A method of tuning a television tuner, comprising:
- operating a single voltage controlled oscillator to provide a non-integer, fractional multiple of a reference signal;
- providing said fractional multiple of said reference signal to a mixer and thereby fine tuning said tuner.
A method of tuning two co-located television tuners, comprising:
- synthesizing a first mixing signal using a first fractional-N frequency synthesiser;
- synthesizing a second mixing signal using a second fractional-N frequency synthesiser;
- 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 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 to fine tune said second channel to a second output intermediate frequency.
Dependencies are inferred from the claim text.