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US4870490A Expired / Lapsed US ⏱️ 0.0 years remaining

Television receiver

Assignee: Hitachi Ltd
•
Filing: 1988-09-23
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Granted: 1989-09-26
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Expires: 2008-09-23
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Abstract

Abstract In a television receiver including a digital circuit processing an input video signal in a digital mode, a clock generating circuit applies a system clock signal to the digital circuit, and comprises a phase comparator to which a horizontal synchronizing signal is applied, a low-pass filter connected to the phase comparator, a voltage controlled oscillator connected to the low-pass filter to generate the system clock signal, a first frequency divider dividing the frequency of the system clock signal generated from the voltage controlled oscillator to generate a horizontal deflection drive pulse signal, and a second frequency divider connected to the phase comparator. The phase comparator, the low-pass filter, the voltage controlled oscillator, the first frequency divider and the second frequency divider constitute a single PLL circuit, and the system clock signal and the horizontal deflection drive pulse signal are respectively generated from the PLL circuit.

Inventors

  • 👤 Hiroshi Sekiya
  • 👤 Ikuya Arai
  • 👤 Toshinori Murata

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-08 14:51
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/04; H04N5/06; H04N5/12; H04N5/126

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 227 words
A television receiver including a digital circuit processing an input video signal in a digital mode, means for scanning an electron beam at a frequency which is n times (n being an integer) as high as that of a horizontal synchronizing signal of said video signal, and a clock generating circuit applying a system clock signal to said digital circuit, said clock generating circuit comprising: a phase comparator having a first input to which said horizontal synchronizing signal is applied; a low-pass filter connected to said phase comparator; a voltage controlled oscillator connected to said low-pass filter to generate the system clock signal having a frequency of (n×m×f H ) which is (n×m) times (m being an integer) as high as the frequency (f H ) of said horizontal synchronizing signal; a 1/m frequency divider dividing the frequency of said system clock signal generated from said voltage controlled oscillator by the factor of m. to generate a horizontal deflection drive pulse signal having a frequency of (n×f H ); and a 1/n frequency divider connected to a second input of said phase comparator, said phase comparator, said low-pass filter, said voltage controlled oscillator, said 1/m frequency divider and said 1/n frequency divider constituting a single PLL circuit, and both of said system clock signal and said horizontal deflection drive pulse signal being generated from said PLL circuit.
Claim 2
Dependent Claim 227 words
A television receiver including a digital circuit processing an input video signal in a digital mode, means for scanning an electron beam at a frequency which is n times (n being an integer) as high as that of a horizontal synchronizing signal of said video signal, and a clock generating circuit applying a system clock signal to said digital circuit, said clock generating circuit comprising: a phase comparator having a first input to which said horizontal synchronizing signal is applied; a low-pass filter connected to said phase comparator; a voltage controlled oscillator connected to said low-pass filter to generate the system clock signal having a frequency of (n×m×f H ) which is (n×m) times (m being an integer) as high as the frequency (f H ) of said horizontal synchronizing signal; a 1/m frequency divider dividing the frequency of said system clock signal generated from said voltage controlled oscillator by the factor of m. to generate a horizontal deflection drive pulse signal having a frequency of (n×f H ); and a 1/n frequency divider connected to a second input of said phase comparator, said phase comparator, said low-pass filter, said voltage controlled oscillator, said 1/m frequency divider and said 1/n frequency divider constituting a single PLL circuit, and both of said system clock signal and said horizontal deflection drive pulse signal being generated from said PLL circuit.
Claim 3
Dependent Claim 317 words
A television receiver including a digital circuit processing an input video signal in a digital mode, means for scanning an electron beam at a frequency which is n times (n=1, 2, . . . ) as high as that of a horizontal synchronizing signal of said video signal, and a clock generating circuit applying a system clock signal to said digital circuit, said clock generating circuit comprising: a phase comparator having a first input to which said horizontal synchronizing signal of said video signal is applied; a low-pass filter connected to said phase comparator; a voltage controlled oscillator connected to said low-pass filter to generate the system clock signal having a frequency of (n×m×f H ) which is (n×m) times (n, m=1, 2, . . . ) as high as the frequency (f H ) of said horizontal synchronizing signal; a 1/m frequency divider dividing the frequency of said system clock signal generated from said voltage controlled oscillator by the factor of m; and a 1/n frequency divider connected to a second input of said phase comparator, the output signal generated at the frequency of (n×f H ) from said 1/m frequency divider being applied to a horizontal output circuit of a horizontal deflection circuit as a horizontal deflection drive pulse signal, a flyback pulse signal generated from a flyback transformer of said horizontal deflection circuit being applied to said 1/n frequency divider to appear as an output signal having a frequency divided by the factor of n, and the phase of said output signal of said 1/n frequency divider being compared in said phase comparator with that of said horizontal synchronizing signal, said phase comparator, said low-pass filter, said voltage controlled oscillator, said 1/m frequency divider and said 1/n frequency divider constituting a single PLL circuit, and both of said system clock signal and said horizontal deflection drive pulse signal being generated from said PLL circuit.
Claim 4
Dependent Claim 317 words
A television receiver including a digital circuit processing an input video signal in a digital mode, means for scanning an electron beam at a frequency which is n times (n=1, 2, . . . ) as high as that of a horizontal synchronizing signal of said video signal, and a clock generating circuit applying a system clock signal to said digital circuit, said clock generating circuit comprising: a phase comparator having a first input to which said horizontal synchronizing signal of said video signal is applied; a low-pass filter connected to said phase comparator; a voltage controlled oscillator connected to said low-pass filter to generate the system clock signal having a frequency of (n×m×f H ) which is (n×m) times (n, m=1, 2, . . . ) as high as the frequency (f H ) of said horizontal synchronizing signal; a 1/m frequency divider dividing the frequency of said system clock signal generated from said voltage controlled oscillator by the factor of m; and a 1/n frequency divider connected to a second input of said phase comparator, the output signal generated at the frequency of (n×f H ) from said 1/m frequency divider being applied to a horizontal output circuit of a horizontal deflection circuit as a horizontal deflection drive pulse signal, a flyback pulse signal generated from a flyback transformer of said horizontal deflection circuit being applied to said 1/n frequency divider to appear as an output signal having a frequency divided by the factor of n, and the phase of said output signal of said 1/n frequency divider being compared in said phase comparator with that of said horizontal synchronizing signal, said phase comparator, said low-pass filter, said voltage controlled oscillator, said 1/m frequency divider and said 1/n frequency divider constituting a single PLL circuit, and both of said system clock signal and said horizontal deflection drive pulse signal being generated from said PLL circuit.
Claim 5
Dependent Claim 344 words
A television receiver including a digital circuit processing in a digital mode an input video signal including a horizontal synchronizing signal having a predetermined frequency (f H ), a clock generating circuit applying a system clock signal to said digital circuit, and a horizontal deflection circuit to which a horizontal deflection drive pulse signal having a frequency of (n×f H ) which is n times (n being an integer) as high as that of said horizontal synchronizing signal is applied from said clock generating circuit, said clock generating circuit comprising: a phase comparator having a first input to which said horizontal synchronizing signal is applied; a low-pass filter connected to said phase comparator; a voltage controlled oscillator connected to said low-pass filter to generate the system clock signal having a frequency of (n×m×f H ) which is (n×m) times (m being an integer) as high as that of said horizontal synchronizing signal; a 1/m frequency divider dividing the frequency of said system clock signal generated from said voltage controlled oscillator by the factor of m to generate the horizontal deflection drive pulse signal having the frequency of (n×f H ); and a 1/n frequency divider connected to a second input of said phase comparator; said horizontal deflection circuit comprising: a horizontal output circuit to which said horizontal deflection drive pulse signal is applied from said 1/m frequency divider; and a flyback transformer generating a flyback pulse signal in response to a horizontal output signal applied from said horizontal output circuit, said 1/n frequency divider dividing the frequency (n×f H ) of said flyback pulse signal by the factor of n, and said phase comparator comparing the phase of the output signal generated at the frequency of f H from said 1/n frequency divider with that of said horizontal synchronizing signal, said phase comparator, said low-pass filter, said voltage controlled oscillator, said 1/m frequency divider and said 1/n frequency divider constituting a single PLL circuit, and both of said system clock signal and said horizontal deflection drive pulse signal being generated from said PLL circuit.
Claim 6
Dependent Claim 344 words
A television receiver including a digital circuit processing in a digital mode an input video signal including a horizontal synchronizing signal having a predetermined frequency (f H ), a clock generating circuit applying a system clock signal to said digital circuit, and a horizontal deflection circuit to which a horizontal deflection drive pulse signal having a frequency of (n×f H ) which is n times (n being an integer) as high as that of said horizontal synchronizing signal is applied from said clock generating circuit, said clock generating circuit comprising: a phase comparator having a first input to which said horizontal synchronizing signal is applied; a low-pass filter connected to said phase comparator; a voltage controlled oscillator connected to said low-pass filter to generate the system clock signal having a frequency of (n×m×f H ) which is (n×m) times (m being an integer) as high as that of said horizontal synchronizing signal; a 1/m frequency divider dividing the frequency of said system clock signal generated from said voltage controlled oscillator by the factor of m to generate the horizontal deflection drive pulse signal having the frequency of (n×f H ); and a 1/n frequency divider connected to a second input of said phase comparator; said horizontal deflection circuit comprising: a horizontal output circuit to which said horizontal deflection drive pulse signal is applied from said 1/m frequency divider; and a flyback transformer generating a flyback pulse signal in response to a horizontal output signal applied from said horizontal output circuit, said 1/n frequency divider dividing the frequency (n×f H ) of said flyback pulse signal by the factor of n, and said phase comparator comparing the phase of the output signal generated at the frequency of f H from said 1/n frequency divider with that of said horizontal synchronizing signal, said phase comparator, said low-pass filter, said voltage controlled oscillator, said 1/m frequency divider and said 1/n frequency divider constituting a single PLL circuit, and both of said system clock signal and said horizontal deflection drive pulse signal being generated from said PLL circuit.

References Cited (Backward Citations)

US3821470A Cited
US4096328A Cited
US4245251A Cited
US4520394A Cited
US4591910A Cited
US4729024A Cited
US4636861A Cited
US4754330A Cited
US4769705A Cited
US4791488A Cited
JPH06281177A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1992-09-25 1993-03-27 1993-09-26 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1996-09-25 1997-03-27 1997-09-26 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2000-09-25 2001-03-27 2001-09-26 $7700.00 Window Closed / Lapsed

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