Wide frequency spectrum television tuner with single local oscillator
First Claim
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1. Apparatus for generating a conversion signal for a mixer, comprising:
- variable oscillator means for generating a first RF signal over a predetermined frequency range;
frequency conversion means for converting the frequency of said first RF signal in accordance with a binary number, N, to provide a second RF signal having a frequency range which varies as a function of said binary number, N, for application to said mixer; and
control means for selecting values of said binary number, N, to provide a respective frequency range for said second RF signal for each selected value of said binary number, N;
first means for applying digital phase shift to said second RF signal to produce a digitally phase shifted signal;
second means for applying analog phase shift to said second RF signal to produce an analog phase shifted signal; and
third means for selecting said analog phase shifted signal for application to said mixer as said second RF signal at frequencies above a given frequency and for selecting said digitally phase shifted signal for application to said mixer as said second RF signal at frequencies below said given frequency.
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Abstract
A tuner includes a conversion (or heterodyning) stage, including a local oscillator and a mixer, for converting an RF signal corresponding to a selected channel to an IF signal. The local oscillator has only one tunable oscillating portion for generating a signal, and a frequency converter, such as a controllable frequency divider, for converting the frequency of the signal generated by said oscillating portion, so that the receiver is able to tune through the UHF and VHF bands. The operation of the requency converter is responsive to a digital controller, such as a microprocessor.
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6 Claims
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1. Apparatus for generating a conversion signal for a mixer, comprising:
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variable oscillator means for generating a first RF signal over a predetermined frequency range; frequency conversion means for converting the frequency of said first RF signal in accordance with a binary number, N, to provide a second RF signal having a frequency range which varies as a function of said binary number, N, for application to said mixer; and control means for selecting values of said binary number, N, to provide a respective frequency range for said second RF signal for each selected value of said binary number, N; first means for applying digital phase shift to said second RF signal to produce a digitally phase shifted signal; second means for applying analog phase shift to said second RF signal to produce an analog phase shifted signal; and third means for selecting said analog phase shifted signal for application to said mixer as said second RF signal at frequencies above a given frequency and for selecting said digitally phase shifted signal for application to said mixer as said second RF signal at frequencies below said given frequency. - View Dependent Claims (2, 3)
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4. A method for generating a conversion signal for a mixer, comprising:
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generating a first RF signal over a predetermined frequency range; converting the frequency of said first RF signal in accordance with a binary number, N, to provide a second RF signal having a frequency range which varies as a function of said binary number, N, for application to said mixer; selecting values of said binary number, N, to provide a respective frequency range for said second RF signal for each selected value of said binary number, N; applying digital phase shift to said second RF signal to produce a digitally phase shifted signal; applying analog phase shift to said second RF signal to produce an analog phase shifted signal; and selecting said analog phase shifted signal for application to said mixer as said second RF signal at frequencies above a given frequency and for selecting said digitally phase shifted signal for application to said mixer as said second RF signal at frequencies below said given frequency. - View Dependent Claims (5, 6)
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Specification