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Patent US4952889A successfully refreshed from Google Patents.
US4952889A
Expired / Lapsed
US
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Loop filter modulated synthesizer
Assignee: Quarterhill Inc
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Filing: 1989-04-28
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Granted: 1990-08-28
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Expires: 2009-04-28
Abstract
Abstract A frequency synthesizer for providing a modulated output signal includes a phase comparator, a loop filter, and a voltage controlled oscillator (VCO). The phase comparator receives a reference input signal and a signal related to the VCO output, and generates a control current. A modulation circuit receives a modulation signal and provides both a modulation current and a modulation voltage. The modulation current is summed with the control current at one input of the loop filter, while the modulation voltage is applied to a second input of the loop filter. The VCO is controlled by the output of the loop filter to produce the modulated output signal.
Inventors
- 👤 James S. Irwin
- 👤 Wayne P. Shepherd
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:19
CPC Classifications
H; H03; H03C; H03C3/00; H03C3/02; H03C3/09; H03C3/0908; H03C3/0975; H03C3/0941; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/085; H03L7/089; H03L7/0891
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
130 words
A frequency synthesizer for providing a modulated output signal, comprising: a filter having an output for controlling a voltage controlled oscillator (VCO) to produce said modulated output signal; a phase comparator means for providing an output current to said filter, said phase comparator means having a first input for a reference signal and a second input for a signal derived from said modulated output signal; first modulation input means including an input for receiving a modulation signal, means for providing a varying current to said filter in response to said modulation signal, and means for summing said varying current and said output current of said phase comparator means in said filter; and second modulation input means for applying a varying voltage to said filter in response to said modulation signal.
Claim 2
Dependent Claim
130 words
A frequency synthesizer for providing a modulated output signal, comprising: a filter having an output for controlling a voltage controlled oscillator (VCO) to produce said modulated output signal; a phase comparator means for providing an output current to said filter, said phase comparator means having a first input for a reference signal and a second input for a signal derived from said modulated output signal; first modulation input means including an input for receiving a modulation signal, means for providing a varying current to said filter in response to said modulation signal, and means for summing said varying current and said output current of said phase comparator means in said filter; and second modulation input means for applying a varying voltage to said filter in response to said modulation signal.
Claim 3
Dependent Claim
44 words
The frequency synthesizer of claim 1 wherein said means for providing said varying current comprises: an integrator means for providing a phase signal in response to said modulation signal; and voltage conversion means for providing said varying current in response to said phase signal.
Claim 4
Dependent Claim
34 words
The frequency synthesizer of claim 1 wherein said summing means comprises said filter being a loop filter including an input for summing said varying current and said output current of said phase comparator means.
Claim 5
Dependent Claim
19 words
The frequency synthesizer of claim 1 wherein said phase comparator means comprises a charge pump type of phase detector.
Claim 6
Dependent Claim
25 words
The frequency synthesizer of claim 1 wherein said means for providing said varying current is responsive to a low frequency portion of said modulation signal.
Claim 7
Dependent Claim
108 words
A frequency synthesizer, comprising: a passive loop filter having an output for controlling a voltage controlled oscillator (VCO) to produce a modulated output signal; a phase comparator for providing a control current to an input of said passive loop filter, said phase comparator having a first input for a reference signal and a second input for a signal derived from said modulated output signal; and said passive loop filter including a modulation input for receiving a modulation signal, means for converting said control current to a voltage signal, and means for summing said modulation signal with said voltage signal, said summing means being coupled to said modulation input.
Claim 8
Dependent Claim
108 words
A frequency synthesizer, comprising: a passive loop filter having an output for controlling a voltage controlled oscillator (VCO) to produce a modulated output signal; a phase comparator for providing a control current to an input of said passive loop filter, said phase comparator having a first input for a reference signal and a second input for a signal derived from said modulated output signal; and said passive loop filter including a modulation input for receiving a modulation signal, means for converting said control current to a voltage signal, and means for summing said modulation signal with said voltage signal, said summing means being coupled to said modulation input.
Claim 9
Dependent Claim
28 words
The frequency synthesizer of claim 6 wherein said summing means comprises a voltage divider for summing a voltage portion of said modulation signal into said passive loop filter.
Claim 10
Dependent Claim
119 words
A frequency synthesizer including a phase comparator and a loop filter, comprising: said loop filter having an output for controlling a voltage controlled oscillator (VCO) to produce a modulated output signal; said phase comparator for providing a control current to an input of said loop filter, said phase comparator having a first input for a reference signal and a second input for signal derived from said modulated output signal; and said loop filter including a modulation input for receiving a modulation signal, means for converting said control current to a voltage signal, and a voltage divider comprising a plurality of capacitors coupled to said modulation input for summing a voltage portion of said modulation signal into said loop filter.
Claim 11
Dependent Claim
119 words
A frequency synthesizer including a phase comparator and a loop filter, comprising: said loop filter having an output for controlling a voltage controlled oscillator (VCO) to produce a modulated output signal; said phase comparator for providing a control current to an input of said loop filter, said phase comparator having a first input for a reference signal and a second input for signal derived from said modulated output signal; and said loop filter including a modulation input for receiving a modulation signal, means for converting said control current to a voltage signal, and a voltage divider comprising a plurality of capacitors coupled to said modulation input for summing a voltage portion of said modulation signal into said loop filter.
Claim 12
Dependent Claim
15 words
The frequency synthesizer of claim 7 wherein said voltage divider comprises a plurality of resistors.
Claim 13
Dependent Claim
116 words
A frequency synthesizer including a phase comparator and an ungrounded loop filter, comprising: said loop filter having an output for controlling a voltage controlled oscillator (VCO) to produce a modulated output signal; said phase comparator for providing a control current to an input of said ungrounded loop filter, said phase comparator having a first input for a reference signal and a second input for a signal derived from said modulated output signal; and said ungrounded loop filter including a modulation input for receiving a modulation signal, means for converting said control current to a voltage signal, and means for summing said modulation signal with said voltage signal, said summing means being coupled to said modulation input.
Claim 14
Dependent Claim
116 words
A frequency synthesizer including a phase comparator and an ungrounded loop filter, comprising: said loop filter having an output for controlling a voltage controlled oscillator (VCO) to produce a modulated output signal; said phase comparator for providing a control current to an input of said ungrounded loop filter, said phase comparator having a first input for a reference signal and a second input for a signal derived from said modulated output signal; and said ungrounded loop filter including a modulation input for receiving a modulation signal, means for converting said control current to a voltage signal, and means for summing said modulation signal with said voltage signal, said summing means being coupled to said modulation input.
Claim 15
Dependent Claim
19 words
The frequency synthesizer of claim 7 wherein said voltage divider includes at least a component of said loop filter.
Claim 16
Dependent Claim
13 words
The frequency synthesizer of claim 6 wherein said summing means comprises passive elements.
Claim 17
Dependent Claim
146 words
A frequency synthesizer for providing a modulated output signal, comprising: a phase comparator means for providing a control current to an input of a loop filter, said phase comparator means having a first input for a reference signal and a second input for a signal derived from said modulated output signal; and said loop filter including an output for controlling a voltage controlled oscillator (VCO) to produce said modulated output signal, a modulation input for receiving a modulation signal, means for converting said control current to a voltage signal, means for summing said modulation signal with said voltage signal, said summing means being coupled to said modulation input, means for providing a varying current in response to said modulation signal coupled to said modulation input and means for summing said varying current and said control current from said phase comparator means at said loop filter input.
Claim 18
Dependent Claim
146 words
A frequency synthesizer for providing a modulated output signal, comprising: a phase comparator means for providing a control current to an input of a loop filter, said phase comparator means having a first input for a reference signal and a second input for a signal derived from said modulated output signal; and said loop filter including an output for controlling a voltage controlled oscillator (VCO) to produce said modulated output signal, a modulation input for receiving a modulation signal, means for converting said control current to a voltage signal, means for summing said modulation signal with said voltage signal, said summing means being coupled to said modulation input, means for providing a varying current in response to said modulation signal coupled to said modulation input and means for summing said varying current and said control current from said phase comparator means at said loop filter input.
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) | 1993-08-27 | 1994-02-26 | 1994-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-27 | 1998-02-26 | 1998-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-27 | 2002-02-26 | 2002-08-28 | $7700.00 | Window Closed / Lapsed |