EP0140567A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Apparatus for controlling the frequency of a voltage controlled oscillator
Assignee: Sony Corp
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Filing: 1984-09-20
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Granted: —
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Expires: 2004-09-20
Abstract
Abstract In an automatic frequency control (AFC) circuit (10) of a video tape recorder, a charge pump circuit (13, 14) is used to form a control signal for a voltage controlled oscillator (VCO) 5 included in the AFC circuit by phase-comparing (12) a horizontal synchronising signal (HSYNC) from a video signal with an output of the VCO 5. An AFC-identification circuit (24) can be added to the AFC circuit (10) to make locking-in of the circuit (10) smooth and fast when the AFC circuit is out of a lock-in range.
Inventors
- 👤 Akihiro C/O Patent Division Kikuchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 21:11
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/10; H04; H04N; H04N5/00; H04N5/04; H04N5/05
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
132 words
Apparatus for apparatus for controlling the frequency of a voltage controlled oscillator (5) in response to a horizontal synchronising signal (HSYNC) of a video signal, the apparatus comprising: (a) frequency-divider means (11) for dividing the frequency of an output of the oscillator (5); and (b) control means (12) for phase-comparing an output of the frequency-divider means (11) with the horizontal synchronising signal (HSYNC) and controlling the frequency of the oscillator (5) in response to the result of the phase-comparison, the control means (12, 13) comprising means for forming a control signal (S8) by using a first pulse signal having a first signal level and a second pulse signal having a second signal level in response to the phase difference between the horizontal synchronising signal (HSYNC) and the output of the oscillator (5).
Claim 2
Dependent Claim
132 words
Apparatus for apparatus for controlling the frequency of a voltage controlled oscillator (5) in response to a horizontal synchronising signal (HSYNC) of a video signal, the apparatus comprising: (a) frequency-divider means (11) for dividing the frequency of an output of the oscillator (5); and (b) control means (12) for phase-comparing an output of the frequency-divider means (11) with the horizontal synchronising signal (HSYNC) and controlling the frequency of the oscillator (5) in response to the result of the phase-comparison, the control means (12, 13) comprising means for forming a control signal (S8) by using a first pulse signal having a first signal level and a second pulse signal having a second signal level in response to the phase difference between the horizontal synchronising signal (HSYNC) and the output of the oscillator (5).
Claim 3
Dependent Claim
32 words
Apparatus according to claim 1, wherein the first pulse signal is synchronised with the horizontal synchronising signal (HSYNC) and the second pulse signal is synchronised with the output of the oscillator (5).
Claim 4
Dependent Claim
42 words
Apparatus according to claim 1 or claim 2, wherein a pulse width of each of the first and second pulse signals is changed in response to the phase difference between the horizontal synchronising signal (HSYNC) and the output of the oscillator (5).
Claim 5
Dependent Claim
85 words
Apparatus according to claim 3, wherein a pulse width of the first pulse signal is expanded in response to the phase difference when the phase of the horizontal synchronising signal (HSYNC) is advanced relative to a reference phase of the output of the oscillator (5) arid a pulse width of the second pulse signal is expanded in response to the phase difference when the phase of the horizontal synchronising signal (HSYNC) is delayed relative to a reference phase of the output of the oscillator (5).
Claim 6
Dependent Claim
38 words
Apparatus according to any one of the preceding claims, comprising means (24) for forming a correcting signal to be added to the control signal when the phase of the horizontal synchronising signal (HSYNC) is beyond a predetermined range.
Claim 7
Dependent Claim
46 words
Apparatus according to any one of the preceding claims, comprising current source means (13) corrected to be supplied with the control signal (S8) and a voltage converting means (14) connected between the current source means (13) and the oscillator (5) to perform a charge pump operation.
Claim 8
Dependent Claim
112 words
Apparatus for apparatus for controlling the frequency of a voltage controlled oscillator (5) in response to a horizontal synchronising signal (HSYNC) of a video signal, the apparatus comprising: (a) frequency-divider means (11) for dividing the frequency of an output of the oscillator (5); (b) control means (12) for phase-comparing an output of the frequency-divider means (11) with the horizontal synchronising signal (HSYNC) and controlling the frequency of the oscillator (5) in response to the result of the phase-comparison; and (c) means (24) for forming a correcting signal to be added to an output of the control means (12) when the phase of the horizontal synchronising signal (HSYNC) is beyond a predetermined range.
Claim 9
Dependent Claim
112 words
Apparatus for apparatus for controlling the frequency of a voltage controlled oscillator (5) in response to a horizontal synchronising signal (HSYNC) of a video signal, the apparatus comprising: (a) frequency-divider means (11) for dividing the frequency of an output of the oscillator (5); (b) control means (12) for phase-comparing an output of the frequency-divider means (11) with the horizontal synchronising signal (HSYNC) and controlling the frequency of the oscillator (5) in response to the result of the phase-comparison; and (c) means (24) for forming a correcting signal to be added to an output of the control means (12) when the phase of the horizontal synchronising signal (HSYNC) is beyond a predetermined range.
Claim 10
Dependent Claim
30 words
Apparatus according to any one of the preceding claims, comprising means (1 to 6) for converting a frequency of the video signal by using the output of the oscillator (5).
Claim 11
Dependent Claim
20 words
Apparatus according to any one of the preceding claims, wherein the dividing ratio of the frequency-divider means (11) is variable.
References Cited (Backward Citations)
No citation records indexed.
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