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US 4,491,976 AGranted
Wide-band tuner having a temperature-compensated microstrip resonator arrangement
AssigneeHitachi, Ltd.
InventorsTakeshi Saitoh, Shigeo Matsuura, Minoru Moteki, Hiroshi Hatashita
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Abstract
A double-superheterodyne tuner for a television receiver comprises a tunable oscillator, a fixed oscillator, two mixer stages and a band-pass filter between the mixer stages, and operates at a GHz intermediate frequency between the mixer stages. The two oscillators and the bandpass filter each includes a microstrip line resonator formed in a dielectric body having substantially the same dielectric constant and dielectric constant temperature coefficient to each other, thereby compensating the variation of the resonant frequency in the resonator due to an ambient temperature variation.
Claims38
A tuner for a television receiver comprising:
- (a) a first mixer for receiving a received RF signal to frequency-convert said RF signal to a first intermediate frequency signal;
- (b) a first variable frequency local oscillator for producing an oscillation signal to excite said first mixer;
- (c) a band-pass filter for selectively passing said first intermediate frequency signal;
- (d) a first intermediate frequency amplifier for amplifying said first intermediate frequency signal;
- (e) a second mixer for receiving the first intermediate frequency signal amplified by said first intermediate frequency amplifier to frequency-convert the first intermediate frequency signal to a second intermediate frequency signal;
- (f) a second local oscillator for producing an oscillation output to excite said second mixer;
- (g) a second intermediate frequency amplifier for selectively amplifying the second intermediate frequency signal output of said second mixer;
- and
- (h) said band-pass filter for selectively passing said first intermediate signal and said second local oscillator including microstrip line resonators constructed on dielectric substrates having an equal dielectric constant and an equal dielectric constant temperature coefficient whereby a variation of a resonant frequency due to an ambient temperature change is compensated.
6 more elements
A tuner for a television receiver comprising:
- (a) a first mixer for receiving a received RF signal to frequency-convert said RF signal to a first intermediate frequency signal;
- (b) a first variable frequency local oscillator for producing an oscillation signal to excite said first mixer;
- (c) a band-pass filter for selectively passing said first intermediate frequency signal;
- (d) a first intermediate frequency amplifier for amplifying said first intermediate frequency signal;
- (e) a second mixer for receiving the first intermediate frequency signal amplified by said first intermediate frequency amplifier to frequency-convert the first intermediate frequency signal to a second intermediate frequency signal;
- (f) a second local oscillator for producing an oscillation output to excite said second mixer;
- (g) a second intermediate frequency amplifier for selectively amplifying the second intermediate frequency signal output of said second mixer;
- and
- (h) said first local oscillator, said band-pass filter for selectively passing said first intermediate signal and said second local oscillator including microstrip line resonators constructed on dielectric substrates having an equal dielectric constant and an equal dielectric constant temperature coefficient whereby a variation of resonant frequency due to an ambient temperature change is compensated.
6 more elements
A tuner for a television receiver comprising:
- (a) a first mixer for receiving a received RF signal to frequency-convert said RF signal to a first intermediate frequency signal;
- (b) a first variable frequency local oscillator for producing an oscillation signal to excite said first mixer;
- (c) a band-pass filter for selectively passing said first intermediate frequency signal;
- (d) a first intermediate frequency amplifier for amplifying said first intermediate frequency signal;
- (e) a second mixer for receiving the first intermediate frequency signal amplified by said first intermediate frequency amplifier to frequency-convert the first intermediate frequency signal to a second intermediate frequency signal;
- (f) a second local oscillator for producing an oscillation output to excite said second mixer;
- (g) a second intermediate frequency amplifier for selectively amplifying the second intermediate frequency signal output of said second mixer;
- (h) said band-pass filter for selectively passing said first intermediate signal and said second local oscillator including microstrip line resonators constructed on dielectric substrates having an equal dielectric constant and an equal dielectric constant temperature coefficient;
- and
- (i) a phase locked loop circuit for combining the outputs of said first and second local oscillators, comparing the combined output with a reference signal and controlling the oscillation frequency of said first local oscillator in accordance with the comparison result such that a frequency difference between the oscillation outputs of said first and second local oscillators is kept constant.
7 more elements
Dependencies are inferred from the claim text.