Patent US5640126A successfully refreshed from Google Patents.
US5640126A
Expired / Lapsed
US
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FM demodulation and frequency tuning for a phase-locked loop
Assignee: STMicroelectronics SA
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Filing: 1996-01-11
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Granted: 1997-06-17
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Expires: 2016-01-11
Abstract
Abstract The invention provides a demodulation PLL wherein: the first position of a switch, which is controlled by a control circuit, respectively connects the outputs of a mixer and a LP filter to high gain and low gain inputs of an oscillator when frequency signals at the inputs of the mixer have not converged sufficiently, i.e. during the PLLs tuning mode; the second position of the switch respectively connects the outputs of the mixer and the LP filter to the low gain and high gain inputs of the oscillator when the frequency signals at the inputs of the mixer and the signal levels on the input and output of the filter have converged sufficiently, i.e. during the PLLs demodulation mode.
Inventors
- 👤 Pascal Mellot
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:15
CPC Classifications
H; H03; H03D; H03D3/00; H03D3/02; H03D3/24; H03D3/241; H03D3/245; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/099; H03L7/10; H03L7/107; H03L7/1075; H03L7/113; H03D2200/00; H03D2200/0001; H03D2200/0025; H03D2200/0027; H03L2207/00; H03L2207/06; H03L7/085; H03L7/087
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
218 words
A demodulation phase-locked loop, comprising: a mixer; a controlled oscillator connected to the mixer, said controlled oscillator having a low gain control input, a high gain control input and an output connected to a first input of the mixer; a first low pass filter having its input connected to an output of the mixer; a level comparator that provides an active output when signal levels on the input and output of the first filter have converged sufficiently; a frequency comparator that provides an active output when the signal frequencies on the first and a second input of the mixer have converged sufficiently; a controlled switch having a first position where the input and output of the first filter are respectively connected to the high gain and low gain inputs of the controlled oscillator and a second position where the input and output of the first filter are respectively connected to the low gain and high gain inputs of the oscillator: and a control means for selecting the first position of the switch when the first and second inputs of the mixer have not converged sufficiently and the second position of the switch when the first and the second inputs of the mixer and the signal levels on the input and output of the first filter have converged sufficiently.
Claim 2
Dependent Claim
218 words
A demodulation phase-locked loop, comprising: a mixer; a controlled oscillator connected to the mixer, said controlled oscillator having a low gain control input, a high gain control input and an output connected to a first input of the mixer; a first low pass filter having its input connected to an output of the mixer; a level comparator that provides an active output when signal levels on the input and output of the first filter have converged sufficiently; a frequency comparator that provides an active output when the signal frequencies on the first and a second input of the mixer have converged sufficiently; a controlled switch having a first position where the input and output of the first filter are respectively connected to the high gain and low gain inputs of the controlled oscillator and a second position where the input and output of the first filter are respectively connected to the low gain and high gain inputs of the oscillator: and a control means for selecting the first position of the switch when the first and second inputs of the mixer have not converged sufficiently and the second position of the switch when the first and the second inputs of the mixer and the signal levels on the input and output of the first filter have converged sufficiently.
Claim 3
Dependent Claim
53 words
A demodulation phase-locked loop according to claim 1, wherein said controlled oscillator comprises a current controlled oscillator and first and second voltage controlled current sources, that respectively have control inputs that correspond to the high gain and low gain inputs of the controlled oscillator, for controlling the frequency of the current controlled oscillator.
Claim 4
Dependent Claim
19 words
A demodulation phase-locked loop according to claim 2, wherein the second voltage controlled current source has high linearity characteristics.
Claim 5
Dependent Claim
38 words
A demodulation phase-locked loop according to claim 1, further comprising a second low pass filter and a buffer that are connected downstream from the mixer and upstream from the first filter, the controlled switch, and the level comparator.
Claim 6
Dependent Claim
18 words
A demodulation phase-locked loop according to claim 1, wherein the first filter is a resistor and capacitor filter.
Claim 7
Dependent Claim
31 words
A demodulation phase-locked loop according to claim 5, further comprising a means for reducing the value of the resistor of the first filter when the switch is in its first position.
Claim 8
Dependent Claim
13 words
A satellite receiver system, comprising a demodulation phase-locked loop according to claim 1.
Claim 9
Dependent Claim
12 words
A radio system, comprising a demodulation phase-locked loop according to claim 1.
Claim 10
Dependent Claim
12 words
A television system, comprising a demodulation phase-locked loop according to claim 1.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-06-16 | 2000-12-16 | 2001-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-06-16 | 2004-12-16 | 2005-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-06-16 | 2008-12-16 | 2009-06-17 | $7700.00 | Window Closed / Lapsed |