Stabilized frequency and phase locked loop with saw devices on common substrate
AssigneeZenith Electronics Corporation
InventorGary J. Sgrignoli
Life of this patent
Estimating the term…
Abstract
A television receiver includes a long loop frequency and phase locked loop (FPLL) in which the tuner voltage is controlled by the output voltage of the FPLL. A SAW bandpass filter couples the IF signal from the tuner to a synchronous demodulator and to the FPLL. An oscillator includes a SAW resonator that is formed on the same substrate as the SAW bandpass filter for supplying a reference signal to the FPLL and to the synchronous demodulator. The common substrate assures tracking between the IF SAW bandpass filter and the oscillator SAW resonator with temperature changes and processing variations.
Claims3
A television signal receiver comprising:
- tuning means for converting a received RF signal to an IF signal of substantially 45 MHz;
- IF SAW bandpass filter means, having a predetermined frequency response characteristic, for processing said IF signal;
- means including oscillator means and a SAW resonator for generating a reference signal, said oscillator means having an output that is an even integer multiple of the IF signal frequency, and including dividing means for producing said IF signal frequency from said output;
- means for synchronously demodulating said IF signal responsive to said reference signal and developing a control signal for application to said tuning means for locking said IF signal to said reference signal;
- and
- said IF SAW bandpass filter means and said SAW resonator being fabricated on a common substrate whereby the frequency of said IF signal tracks variations in said predetermined frequency response characteristic.
A television receiver comprising tuner means for converting a received RF signal to an IF signal of substantially 45 Mhz;
- a SAW bandpass filter having a predetermined frequency response characteristic for processing said IF signal;
- oscillator means, including a SAW resonator, for developing a reference signal;
- frequency and phase locked loop means coupled to said oscillating means and to said SAW bandpass filter for developing a control voltage for said tuning means;
- synchronous demodulator means coupled to said SAW bandpass filter and to said oscillator means for developing a baseband video signal from said IF signal;
- and
- said SAW bandpass filter and said SAW resonator being formed on the same lithium niobate substrate and further including;
- means for minimizing crosstalk between said SAW bandpass filter and said SAW resonator, said crosstalk minimizing means comprises a pattern of ink on said substrate individually surrounding said SAW bandpass filter and aid SAW resonator, whereby changes in temperature and frequency of said SAW bandpass filter or said SAW resonator have minimal effect on their tracking.
A television signal receiver comprising:
- tuning means for converting a received RF signal to an IF signal of substantially 45 MHz;
- IF SAW bandpass filter means, having a predetermined frequency response characteristic, for processing said IF signal;
- means including oscillator means and a SAW resonator for generating a reference signal;
- means for synchronously demodulating said IF signal responsive to said reference signal and developing a control signal for application to said tuning means for locking said IF signal to said reference signal;
- said IF SAW bandpass filter means and said SAW resonator being fabricated on a common lithium niobate substrate whereby the frequency of said IF signal tracks variations in said predetermined frequency response characteristic;
- and
- crosstalk minimizing means comprising a pattern of ink on said common substrate individually surrounding said SAW devices.
Dependencies are inferred from the claim text.