US3593179A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Phase discriminator for synchronizing a local oscillator
Assignee: US Philips Corp
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Filing: 1969-10-22
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Granted: 1971-07-13
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Expires: 1989-10-22
Abstract
Abstract A phase discriminator for synchronizing a local oscillator, particularly for the synchronization of the line deflection in a television receiver. The discriminator is provided with a semiconductor switch and a control stage connected to a control electrode of the switch. The control stage provides, under the influence of an external synchronizing signal applied thereto, a switching signal having short switching pulses relative to a reference potential for closing the semiconductor switch. A source for supplying a comparison signal derived from the oscillator signal can be connected through the switch to a capacitor which conveys a control voltage for a frequency control stage of the oscillator. The discriminator further comprises a peak rectifier circuit having a terminal to which the source is connected. The peak rectifier circuit includes a potential divider which provides a threshold in the comparison signal relative to the reference potential occurring in the switching signal which is applied to the control electrode of the switch by the control stage during the absence of switching pulses; the threshold introduced in the comparison signal maintaining the semiconductor switch open during the absence of switching pulses.
Inventors
- 👤 Paulus Joseph Maria Hovens
- 👤 Wouter Smeulers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 08:48
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/04; H04N5/12; H04N5/126; H03; H03D; H03D13/00; H03D13/005; H03D13/006
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
204 words
A phase discriminator for synchronizing a local oscillator comprising a semiconductor switching means, a control stage connected to the control electrode of said switching means for receiving external synchronizing signals and producing a switching signal therefrom, said switching signal comprising short switching pulses having amplitudes relative to a reference potential for closing said switching means, said reference potential being the potential applied to the control electrode of said switching means during the absence of switching pulses, a source of comparison signals connected to said switching means, said comparison signals being derived from said local oscillator, the closing of said switching means producing a control voltage representing the phase relationship between said switching and comparison signals, a peak rectifier circuit connected between sAid source and said switching means and comprising a potential divider that establishes a threshold level in the amplitude of said comparison signals relative to said reference potential for maintaining said switching means open during the absence of switching pulses, a capacitor for receiving said control voltage, and frequency control means connected between said capacitor and said source for using said control voltage to vary the frequency of said source to minimize differences in the phase relationship between said synchronous and comparison signals.
Claim 2
Dependent Claim
204 words
A phase discriminator for synchronizing a local oscillator comprising a semiconductor switching means, a control stage connected to the control electrode of said switching means for receiving external synchronizing signals and producing a switching signal therefrom, said switching signal comprising short switching pulses having amplitudes relative to a reference potential for closing said switching means, said reference potential being the potential applied to the control electrode of said switching means during the absence of switching pulses, a source of comparison signals connected to said switching means, said comparison signals being derived from said local oscillator, the closing of said switching means producing a control voltage representing the phase relationship between said switching and comparison signals, a peak rectifier circuit connected between sAid source and said switching means and comprising a potential divider that establishes a threshold level in the amplitude of said comparison signals relative to said reference potential for maintaining said switching means open during the absence of switching pulses, a capacitor for receiving said control voltage, and frequency control means connected between said capacitor and said source for using said control voltage to vary the frequency of said source to minimize differences in the phase relationship between said synchronous and comparison signals.
Claim 3
Dependent Claim
58 words
A phase discriminator as claimed in claim 1 wherein said switching means comprises a first and second transistor of the same type having bases connected to said control stage, the emitter of the first transistor connected to the collector of the second transistor and the collector of the first transistor connected to the emitter of the second transistor.
Claim 4
Dependent Claim
56 words
A phase discriminator as claimed in claim 1 wherein said control stage comprises a first transistor in cascade with a second transistor, said first transistor being cut off and said second transistor bottoming when said synchronizing signals are absent and said first transistor bottoming and second transistor being cut off when said synchronizing signals are present.
Claim 5
Dependent Claim
56 words
A phase discriminator as claimed in claim 3 wherein the emitter of the first transistor and the collector of the second transistor of said switching means is connected to said capacitor and the collector of the first transistor and the emitter of the second transistor of said switching means is connected to said peak rectifier circuit.
Claim 6
Dependent Claim
57 words
A phase discriminator as claimed in claim 1 comprising a series arrangement of said switching means and a resistor in parallel with said capacitor, the junction of said resistor and said capacitor being connected to a terminal of a charge capacitor, the junction of said resistor and said switching means being connected to said peak rectifier circuit.
Claim 7
Dependent Claim
25 words
A phase discrimination as claimed in claim 5 wherein said source is in parallel with the series arrangement of said resistor and said charge capacitor.
Claim 8
Dependent Claim
37 words
A phase discriminator as claimed in claim 1 wherein said peak rectifier circuit further comprises a rectifier in series with said potential divider, said potential divider being a series resistor arrangement comprising at least one semiconductor parameter.
Claim 9
Dependent Claim
48 words
A phase discrimination as claimed in claim 1 wherein said source comprises a pulsatory voltage source in parallel with an integrating network, said network comprising a series arrangement of a resistor and capacitor, said junction between said resistor and said capacitor being connected to said peak rectifier circuit.
Claim 10
Dependent Claim
28 words
A phase discriminator as claimed in claim 1 wherein said control stage, said switching means, said source and said frequency control means are integrated within a semiconductor body.
Claim 11
Dependent Claim
197 words
A television receiver with a phase discriminator for synchronizing a line oscillator comprising a semiconductor switch, a control stage connected to the control electrode of said switch for receiving synchronizing signals and producing a switching signal therefrom, said switching signal having short switching pulses relative to a reference potential for closing said semiconductor switch, said reference potential being the potential applied to the control electrode of said switch during the absence of switching pulses, a source of comparison signals connected to said switch, said comparison signals being derived from said line oscillator, the closing of said switch producing a control voltage representing the phase relationship between said switching and comparison signals, a peak rectifier circuit connected between said source and said switch comprising a potential divider that establishes a threshold level in the amplitude of said comparison signals relative to said reference for maintaining said switch open during the absence of said switching pulses, a capacitor for receiving said control vOltage and frequency control means connected between said capacitor and said source for using said control voltage to vary the frequency of said source to minimize differences in the phase relationships between said synchronous and comparison signals.
Claim 12
Dependent Claim
197 words
A television receiver with a phase discriminator for synchronizing a line oscillator comprising a semiconductor switch, a control stage connected to the control electrode of said switch for receiving synchronizing signals and producing a switching signal therefrom, said switching signal having short switching pulses relative to a reference potential for closing said semiconductor switch, said reference potential being the potential applied to the control electrode of said switch during the absence of switching pulses, a source of comparison signals connected to said switch, said comparison signals being derived from said line oscillator, the closing of said switch producing a control voltage representing the phase relationship between said switching and comparison signals, a peak rectifier circuit connected between said source and said switch comprising a potential divider that establishes a threshold level in the amplitude of said comparison signals relative to said reference for maintaining said switch open during the absence of said switching pulses, a capacitor for receiving said control vOltage and frequency control means connected between said capacitor and said source for using said control voltage to vary the frequency of said source to minimize differences in the phase relationships between said synchronous and comparison signals.
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) | 1974-07-12 | 1975-01-11 | 1975-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-12 | 1979-01-11 | 1979-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-12 | 1983-01-11 | 1983-07-13 | $7700.00 | Window Closed / Lapsed |