US5095288A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Phase-locked loop having a variable bandwidth
Assignee: Telefonaktiebolaget LM Ericsson AB
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Filing: 1990-11-13
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Granted: 1992-03-10
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Expires: 2010-11-13
Abstract
Abstract A phase-locked loop having a variable bandwidth and comprising a controlled oscillator, a phase comparison device, two current generating devices (21-22, 25-26) and a loop filter (23-24). Each of the current generating devices is intended to produce a positive or a negative pulsed current in response to signals from the phase comparison device. The outputs of the current generating devices are each connected to a respective point in the loop filter. The loop bandwidth can be varied continuously while maintaining a desired damping factor, by increasing the amplitude of the currents from each of the current generating devices (21-22, 25-26) when the bandwidth is to be increased, and vice versa.
Inventors
- 👤 Paul W. Dent
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:40
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/085; H03L7/089; H03L7/0891; H03L7/0893; H03L7/10; H03L7/107; H03L7/1075; H03L2207/00; H03L2207/04; H03L7/0895; H03L7/0898
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
194 words
A phase-locked loop of variable bandwidth comprising: a controlled oscillator for generating a signal of variable frequency; a phase comparison device; a filter circuit, including at least one resistive element and at least one capacitive element, for producing a control signal to control said oscillator; first and second controllable current-generating devices, each being constructed to generate a positive or a negative pulsed current in response to output signals from the phase comparison device, said first current-generating device having an output connected to a first point in the filter circuit and said second current-generating device having an output connected to a second point in the filter circuit; and a control device for controlling the amplitudes of said currents generated by said current-generating devices said control device being operative to change the amplitudes of the currents from each of the current-generating devices in a first direction to produce a change of the phase-locked loop bandwidth in one direction and to change said amplitudes in another direction to produce a change in the phase-locked loop bandwidth in the other direction, to thereby enable the phase-locked loop bandwidth to be varied continuously while maintaining a desired damping factor.
Claim 2
Dependent Claim
194 words
A phase-locked loop of variable bandwidth comprising: a controlled oscillator for generating a signal of variable frequency; a phase comparison device; a filter circuit, including at least one resistive element and at least one capacitive element, for producing a control signal to control said oscillator; first and second controllable current-generating devices, each being constructed to generate a positive or a negative pulsed current in response to output signals from the phase comparison device, said first current-generating device having an output connected to a first point in the filter circuit and said second current-generating device having an output connected to a second point in the filter circuit; and a control device for controlling the amplitudes of said currents generated by said current-generating devices said control device being operative to change the amplitudes of the currents from each of the current-generating devices in a first direction to produce a change of the phase-locked loop bandwidth in one direction and to change said amplitudes in another direction to produce a change in the phase-locked loop bandwidth in the other direction, to thereby enable the phase-locked loop bandwidth to be varied continuously while maintaining a desired damping factor.
Claim 3
Dependent Claim
38 words
A phase-locked loop according to claim 1, said second point being a connection point between said resistive element and said capacitive element and said first point being a terminal on the resistive element other than said connection point.
Claim 4
Dependent Claim
28 words
The phase-locked loop of claim 2, wherein said control device controls the amplitudes of the currents generated by said first and second current-generating devices independently of one another.
Claim 5
Dependent Claim
33 words
A phase-locked loop according to claim 3, wherein said control device controls the amplitude of the current from the second current-generating device to be zero when a low phase-locked loop bandwidth is desired.
Claim 6
Dependent Claim
164 words
A phase-locked loop of variable bandwidth comprising: a controlled oscillator for generating a signal of variable frequency; a phase comparison device; a filter circuit for producing a control signal to control said oscillator; a plurality of controllable current-generating devices, each being constructed to generate a positive or a negative pulsed current in response to output signals from the phase comparison device, each current-generating device having an output connected to a separate point in the filter circuit; and a control device for controlling the amplitudes of said currents generated by said current-generating devices said control device being operative to change the amplitudes of the currents from each of the current-generating devices in a first direction to produce a change of the phase-locked loop bandwidth in one direction and to change said amplitudes in another direction to produce a change in the phase-locked loop bandwidth in the other direction, to thereby enable the phase-locked loop bandwidth to be varied continuously while maintaining a desired damping factor.
Claim 7
Dependent Claim
164 words
A phase-locked loop of variable bandwidth comprising: a controlled oscillator for generating a signal of variable frequency; a phase comparison device; a filter circuit for producing a control signal to control said oscillator; a plurality of controllable current-generating devices, each being constructed to generate a positive or a negative pulsed current in response to output signals from the phase comparison device, each current-generating device having an output connected to a separate point in the filter circuit; and a control device for controlling the amplitudes of said currents generated by said current-generating devices said control device being operative to change the amplitudes of the currents from each of the current-generating devices in a first direction to produce a change of the phase-locked loop bandwidth in one direction and to change said amplitudes in another direction to produce a change in the phase-locked loop bandwidth in the other direction, to thereby enable the phase-locked loop bandwidth to be varied continuously while maintaining a desired damping factor.
Claim 8
Dependent Claim
26 words
A phase-locked loop of variable bandwidth according to claim 5 wherein said filter circuit includes at least two resistive elements and at least two capacitive elements.
Claim 9
Dependent Claim
31 words
A phase-locked loop according to claim 6, said separate points each being a separate connection point between differing ones of said resistive elements and at least one of said capacitive elements.
Claim 10
Dependent Claim
27 words
The phase-locked loop of claim 7, wherein said control device controls the amplitudes of the currents generated by each of said current-generating devices independently of one another.
Claim 11
Dependent Claim
34 words
A phase-locked loop according to claim 8, wherein said control device controls the amplitude of the current from one of the current-generating devices to be zero when a low phase-locked loop bandwidth is desired.
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) | 1995-03-10 | 1995-09-09 | 1996-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-10 | 1999-09-09 | 2000-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-10 | 2003-09-09 | 2004-03-10 | $7700.00 | Window Closed / Lapsed |