US3821658A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Phase locked loop with memory
Assignee: Signetics Corp
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Filing: 1973-04-26
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Granted: 1974-06-28
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Expires: 1993-04-26
Abstract
Abstract An integrated circuit phase locked loop which includes a low pass filter for preventing carrier dropout which has a long time constant. Such time constant is provided by current mirrors connected to the phase comparator of the phase locked loop which effectively drop the full supply voltage in the form of complementary error currents across relatively high impedance resistors.
Inventors
- 👤 W Hoeft
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:09
CPC Classifications
H; H04; H04S; H04S3/00; H04S3/006; H03; H03D; H03D3/00; H03D3/02; H03D3/24; H03D3/241; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/14
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
171 words
In an integrated circuit phase locked loop, a voltage controlled oscillator (VCO) responsive to the magnitude of an input control signal for producing an output signal having a frequency related to such magnitude; a phase detector for comparing the phase of an input signal with the phase of said output signal of said VCO and producing an error signal in the form of complementary currents in response to a lack of phase coincidence; means for coupling said error signal to said VCO to serve as said input control signal including memory means having charge storage means coupled to high impedance means said high impedance means including current mirror means coupled to said phase detector for reflecting said complementary error signal currents from said phase detector and including a pair of high impedance resistors for terminating such reflected currents to provide a slow charge decay for said memory means said charge storage means being coupled across said resistor pair and said error signal being coupled to said VCO from said memory means.
Claim 2
Dependent Claim
171 words
In an integrated circuit phase locked loop, a voltage controlled oscillator (VCO) responsive to the magnitude of an input control signal for producing an output signal having a frequency related to such magnitude; a phase detector for comparing the phase of an input signal with the phase of said output signal of said VCO and producing an error signal in the form of complementary currents in response to a lack of phase coincidence; means for coupling said error signal to said VCO to serve as said input control signal including memory means having charge storage means coupled to high impedance means said high impedance means including current mirror means coupled to said phase detector for reflecting said complementary error signal currents from said phase detector and including a pair of high impedance resistors for terminating such reflected currents to provide a slow charge decay for said memory means said charge storage means being coupled across said resistor pair and said error signal being coupled to said VCO from said memory means.
Claim 3
Dependent Claim
42 words
A phase locked loop in claim 1 whEre said current mirror means is connected to a dc supply voltage and where said current means drops a large voltage of the order of magnitude of the dc supply voltage across said resistor pair.
Claim 4
Dependent Claim
47 words
A phase locked loop as in claim 1 where said complementary error signal currents are respectively coupled to an audio amplifier and a lock range control of said VCO by means of Darlington connected transistors which provide a high input impedance with respect to said complementary currents.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |