Patent US4851785A successfully refreshed from Google Patents.
US4851785A
Expired / Lapsed
US
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Circuit arrangement for detecting whether a predetermined frequency swing is exceeded
Assignee: US Philips Corp
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Filing: 1988-01-27
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Granted: 1989-07-25
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Expires: 2008-01-27
Abstract
Abstract A circuit arrangement for detecting whether the frequency of an input signal exceeds a predetermined frequency swing. The arrangement includes a detector circuit which supplies an error-indication signal if the phase shift between the input signal and a second signal, which second signal tracks the frequency of the input signal, exceeds limit values corresponding to such frequency swing. A delay circuit derives the second signal from the input signal by delaying the input signal a predetermined delay time which increases with the frequency of the input signal.
Inventors
- 👤 Heinz H. Gehrt
- 👤 Gunter Hildebrandt
- 👤 Karl-Heinz Rehfeldt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:41
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/76; H04N5/91; H04N5/93; H04N5/94
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
88 words
A circuit arrangement for detecting whether a predetermined frequency swing is exceeded by the frequency of an input signal thereto, comprising a detector which supplies an error-indication signal if the phase shift between the input signal and a second signal, which second signal tracks the frequency of the input signal, exceeds limit values corresponding to said frequency swing; characterized in that a delay circuit is included in said detector which derives the second signal from the input signal by delaying the input signal by a predetermined delay time.
Claim 2
Dependent Claim
88 words
A circuit arrangement for detecting whether a predetermined frequency swing is exceeded by the frequency of an input signal thereto, comprising a detector which supplies an error-indication signal if the phase shift between the input signal and a second signal, which second signal tracks the frequency of the input signal, exceeds limit values corresponding to said frequency swing; characterized in that a delay circuit is included in said detector which derives the second signal from the input signal by delaying the input signal by a predetermined delay time.
Claim 3
Dependent Claim
23 words
A circuit arrangement as claimed in claim 1, characterized in that the delay time is substantially constant at least within said frequency swing.
Claim 4
Dependent Claim
37 words
A circuit arrangement as claimed in claim 1, characterized in that the delay time is zero at the lower limit of said frequency swing and within said frequency swing increases with the frequency of said input signal.
Claim 5
Dependent Claim
123 words
A circuit arrangement as claimed in claim 2 or 3, characterized in that the delay circuit comprises a multivibrator circuit having two circuit branches, each circuit branch comprising a series arrangement of a resistor (30 and 34 respectively), the main current path of a transistor (31 and 35 respectively), and a switchable current source (32, 33 and 36, 33 respectively); the junction points between the main current paths of the transistors and the switchable current sources in the respective circuit branches being connected to one another by a capacitance (38); and the control terminal of the transistor in each circuit branch being coupled to the junction point between the main current path of the transistor and the resistor in the other circuit branch.
Claim 6
Dependent Claim
33 words
A circuit arrangement as claimed in claim 4, characterized in that the switchable current source in each circuit branch is connected in parallel with a source (321 and 361 respectively) of constant current.
Claim 7
Dependent Claim
44 words
A circuit arrangement as claimed in any of claims 1, 2 or 3, characterized in that the delay circuit forms part of a frequency demodulator (20) in which the input signal and the second signal are combined by means of an exclusive-OR circuit (21).
Claim 8
Dependent Claim
28 words
A circuit arrangement as claimed in any one of claims 1, 2 or 3, characterized in that it is comprised in an apparatus for playing back disc records.
Claim 9
Dependent Claim
39 words
A circuit arrangement as claimed in claim 4, characterized in that the delay circuit forms part of a frequency demodulator (20) in which the input signal and the second signal are combined by means of an exclusive-OR circuit (21).
Claim 10
Dependent Claim
22 words
A circuit arrangement as claimed in claim 4, characterized in that it is comprised in an apparatus for playing back disc records.
References Cited (Backward Citations)
US3778727A
Cited
US4403185A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-24 | 1993-01-23 | 1993-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-24 | 1997-01-23 | 1997-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-24 | 2001-01-23 | 2001-07-25 | $7700.00 | Window Closed / Lapsed |