US5963100A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency synthesizer having a speed-up circuit
Assignee: NEC Corp
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Filing: 1998-02-24
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Granted: 1999-10-05
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Expires: 2018-02-24
Abstract
Abstract It is an object of the present invention to provide a frequency synthesiser with a lock speed-up arrangement in a simple and effective form. In accordance with the invention there is provided a frequency synthesiser including a voltage controlled oscillator, a phase detector which receives a base frequency signal and a feedback signal derived from the output of the voltage controlled oscillator and a filter circuit connecting the output of phase detector to a frequency control voltage input of the voltage controlled oscillator, the filter circuit having a reference voltage connection, and a speed-up circuit for applying a voltage signal to the reference voltage connection when a frequency change is demanded.
Inventors
- 👤 Nigel Tolson
- 👤 Justin Clark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 03:50
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/16; H03L7/18; H03L7/183; H03L7/187; H03L7/189
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
103 words
A frequency synthesizer comprising: a voltage controlled oscillator having an oscillator output; a phase detector which receives a base frequency signal and a feedback signal derived from said oscillator output, and which has a phase detector output; a filter circuit connecting said phase detector output to a frequency control voltage input of said voltage controlled oscillator, wherein said filter circuit has a reference voltage connection; and a speed-up circuit comprising an output connection capacitively coupled to said reference voltage connection of said filter circuit, and a first resistor coupled between said reference voltage connection of said filter circuit and a reference voltage source.
Claim 2
Dependent Claim
103 words
A frequency synthesizer comprising: a voltage controlled oscillator having an oscillator output; a phase detector which receives a base frequency signal and a feedback signal derived from said oscillator output, and which has a phase detector output; a filter circuit connecting said phase detector output to a frequency control voltage input of said voltage controlled oscillator, wherein said filter circuit has a reference voltage connection; and a speed-up circuit comprising an output connection capacitively coupled to said reference voltage connection of said filter circuit, and a first resistor coupled between said reference voltage connection of said filter circuit and a reference voltage source.
Claim 3
Dependent Claim
38 words
A frequency synthesizer as claimed in claim 1, in which said speed-up circuit includes a plurality of analog switch devices controlling the connection of a like number of voltage sources to said output connection of said speed-up circuit.
Claim 4
Dependent Claim
37 words
A frequency synthesizer as claimed in claim 1, in which said speed-up circuit comprises a digital to analog converter for applying to said output connection of said speed-up circuit a voltage dependent on an input digital signal.
Claim 5
Dependent Claim
54 words
A frequency synthesizer as claimed in claim 1, further comprising a frequency divider connected to provide said feedback signal to said phase detector, and a control circuit connected to said frequency divider to control a frequency division ratio of said frequency divider, said control circuit also providing a control signal to said speed-up circuit.
Claim 6
Dependent Claim
54 words
A frequency synthesizer as claimed in claim 2, further comprising a frequency divider connected to provide said feedback signal to said phase detector, and a control circuit connected to said frequency divider to control a frequency division ratio of said frequency divider, said control circuit also providing a control signal to said speed-up circuit.
Claim 7
Dependent Claim
54 words
A frequency synthesizer as claimed in claim 3, further comprising a frequency divider connected to provide said feedback signal to said phase detector, and a control circuit connected to said frequency divider to control a frequency division ratio of said frequency divider, said control circuit also providing a control signal to said speed-up circuit.
Claim 8
Dependent Claim
138 words
A frequency synthesizer as claimed in claim 1, wherein said speed-up circuit further comprises: a second resistor, a third resistor, and a fourth resistor connected in series between two voltage sources, having a first node between said second resistor and said third resistor, and having a second node between said third resistor and said fourth resistor; a first analog switch connected between said first node and said output connection of said speed-up circuit; a second analog switch connected between said second node and said output connection of said speed-up circuit; a control circuit for providing a binary control signal to said speed-up circuit in response to a frequency change request; and wherein said binary control signal is applied to said first analog switch and said second analog switch for selectively activating said first node or said second node.
Claim 9
Dependent Claim
61 words
A frequency synthesizer as claimed in claim 7, further comprising: a frequency divider connected to said control circuit, to said voltage controlled oscillator, and to said phase detector; wherein said control circuit controls a frequency division ratio of said frequency divider; and wherein said frequency divider provides said feedback signal to said phase detector in accordance with said frequency division ratio.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-10-04 | 2003-04-05 | 2003-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-10-04 | 2007-04-05 | 2007-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-10-04 | 2011-04-05 | 2011-10-05 | $7700.00 | Window Closed / Lapsed |