US5389898A
Expired / Lapsed
US
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Phase locked loop having plural selectable voltage controlled oscillators
Assignee: Panasonic Holdings Corp
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Filing: 1993-06-22
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Granted: 1995-02-14
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Expires: 2013-06-22
Abstract
Abstract The invention discloses a PLL formed by a phase detector, a filter, three VCO's (VCO1, VCO2, and VCO3), a multiplexer, and a frequency divider. The VCO1, VCO2, and VCO3 have different mean frequencies, each oscillating at a frequency controlled according to the voltage value of a phase control signal from the filter. The multiplexer selects one of the VCO's which operate in parallel. If a pulse of a digital phase difference signal UP indicating that an internal signal is delayed in phase with respect to a reference signal is output twice in succession, or if a pulse of a digital phase difference signal DOWN indicating that an internal signal is advanced in phase with respect to a reference signal is output twice in succession, a counter makes the multiplexer change its current VCO selection via a shift register. Accordingly, high-speed PLL pulling is achievable even if a PLL frequency variable-range is expanded.
Inventors
- 👤 Osamu Taketoshi
- 👤 Tsuguyasu Hatsuda
- 👤 Seiji Yamaguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 02:43
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/085; H03L7/089; H03L7/099; H03L7/0995; H03L7/0997; H03L7/10; H03L7/101; H03L7/102; H03L7/16; H03L7/18; H03L7/183
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
145 words
A phase-locked loop comprising: a phase detector for comparing the phase of a reference signal with the phase of an internal signal to produce a phase difference signal proportional to the phase difference found between the signals, a filter for producing a phase control signal with a voltage value proportional to the phase difference signal, a plurality of voltage-controlled oscillators with different mean frequencies which oscillate at a frequency controlled according to the voltage value of the phase control signal, a selector for selecting one of the outputs of said plurality of voltage-controlled oscillators on the basis of the phase difference signal or the phase control signal, and a frequency divider for dividing the frequency of the selected output to produce said internal signal, wherein, when said phase control signal changes its voltage value, said plurality of voltage-controlled oscillators vary their output frequencies equal amounts.
Claim 2
Dependent Claim
145 words
A phase-locked loop comprising: a phase detector for comparing the phase of a reference signal with the phase of an internal signal to produce a phase difference signal proportional to the phase difference found between the signals, a filter for producing a phase control signal with a voltage value proportional to the phase difference signal, a plurality of voltage-controlled oscillators with different mean frequencies which oscillate at a frequency controlled according to the voltage value of the phase control signal, a selector for selecting one of the outputs of said plurality of voltage-controlled oscillators on the basis of the phase difference signal or the phase control signal, and a frequency divider for dividing the frequency of the selected output to produce said internal signal, wherein, when said phase control signal changes its voltage value, said plurality of voltage-controlled oscillators vary their output frequencies equal amounts.
Claim 3
Dependent Claim
21 words
A phase-locked loop as in claim 1, wherein said plurality of voltage-controlled oscillators have different frequency variable-ranges which overlap one another.
Claim 4
Dependent Claim
37 words
A phase-locked loop as in claim 1, wherein said selector selects one of the outputs of said plurality of voltage-controlled oscillators on the basis of the hysteresis of the phase difference signal or the phase control signal.
Claim 5
Dependent Claim
38 words
A phase-locked loop as in claim 1, wherein said selector has a configuration which permits said selector to select one of the outputs of said plurality of voltage-controlled oscillators under control from the outside of said phase-locked loop.
Claim 6
Dependent Claim
26 words
A phase-locked loop as in claim 1, wherein said frequency divider has a divide ratio of 1/n, with the number n being a positive integral number.
Claim 7
Dependent Claim
165 words
A phase-locked loop comprising: a phase detector for comparing the phase of a reference signal with the phase of an internal signal to produce a phase difference signal proportional to the phase difference found between the signals, a filter for producing a phase control signal with a voltage value proportional to the phase difference signal, a plurality of voltage-controlled oscillators with different mean frequencies which oscillate at a frequency controlled according to the voltage value of the phase control signal, a controller for switching between the oscillating state and the stopped state of each of said plurality of voltage-controlled oscillators, a selector for selecting one of the outputs of said plurality of voltage-controlled oscillators on the basis of the phase difference signal or the phase control signal, and a frequency divider for dividing the frequency of the selected output to produce said internal signal, wherein, when a phase control signal changes its voltage value, said plurality of voltage-controlled oscillators vary their output frequencies equal amounts.
Claim 8
Dependent Claim
165 words
A phase-locked loop comprising: a phase detector for comparing the phase of a reference signal with the phase of an internal signal to produce a phase difference signal proportional to the phase difference found between the signals, a filter for producing a phase control signal with a voltage value proportional to the phase difference signal, a plurality of voltage-controlled oscillators with different mean frequencies which oscillate at a frequency controlled according to the voltage value of the phase control signal, a controller for switching between the oscillating state and the stopped state of each of said plurality of voltage-controlled oscillators, a selector for selecting one of the outputs of said plurality of voltage-controlled oscillators on the basis of the phase difference signal or the phase control signal, and a frequency divider for dividing the frequency of the selected output to produce said internal signal, wherein, when a phase control signal changes its voltage value, said plurality of voltage-controlled oscillators vary their output frequencies equal amounts.
Claim 9
Dependent Claim
21 words
A phase-locked loop as in claim 6, wherein said plurality of voltage-controlled oscillators have different frequency variable-ranges which overlap one another.
Claim 10
Dependent Claim
23 words
A phase-locked loop as in claim 6, wherein the operation of said controller is controlled on the basis of the phase difference signal.
Claim 11
Dependent Claim
37 words
A phase-locked loop as in claim 6, wherein said selector selects one of the outputs of said plurality of voltage-controlled oscillators on the basis of the hysteresis of the phase difference signal or the phase control signal.
Claim 12
Dependent Claim
38 words
A phase-locked loop as in claim 6, wherein said selector has a configuration which permits said selector to select one of the outputs of said plurality of voltage-controlled oscillators under control from the outside of said phase-locked loop.
Claim 13
Dependent Claim
26 words
A phase-locked loop as in claim 6, wherein said frequency divider has a divide ratio of 1/n, with the number n being a positive integral number.
References Cited (Backward Citations)
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