Jitter correction circuit
First Claim
1. A jitter correction circuit comprising:
- analog-to-digital converting circuit converts an input reproduced compressed video signal to a digital signal based on an input clock pulse;
a phase deviation detection circuit connected to said analog-to-digital converting circuit, said phase deviation detection circuit latches said digital signal and detects an amount of deviation of said digital signal, said phase deviation detection circuit producing a phase deviation;
digital-to-analog converting circuit converts said phase deviation to an analog signal;
a first low-pass filter connected to said digital-to-analog converting circuit, said first low-pass filter setting a cut-off frequency of said analog signal approximately equal to a horizontal synchronizing signal;
a first control oscillation circuit receives said horizontal synchronized signal from said first low-pass filter and provides a first oscillation output having a rapid frequency response characteristic based on said phase deviation of said horizontal synchronized signal contained in said reproduced compressed video signal;
a timing pulse generating circuit receives said first oscillation output from said first control oscillation circuit and produces said clock pulse input to said analog-to-digital converting circuit, wherein said analog-to-digital converting circuit samples said reproduced video signal based on said first oscillation output to provide said digital signal by analog-to-digital conversion;
a second oscillation control circuit provides a second oscillation output having a stable frequency response characteristic based on at least one of a phase deviation of said horizontal synchronized signal and a phase deviation of said first oscillation output; and
a resampling circuit resamples said digital signal from said analog-to-digital converting circuit based on said second oscillation output.
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Accused Products
Abstract
A jitter correction circuit is a circuit for suppressing a jitter contained in a reproduced digital signal. This jitter correction circuit comprises a phase-locked loop circuit comprising a phase comparing circuit (9), a second low-pass filter (10), a second voltage control oscillator (11) and a second frequency dividing circuit (12). The phase-locked loop circuit provides an oscillation output which causes little influence to a jitter component contained in a reproduced signal digitally converted by an analog-to-digital converting circuit (1). The digitally converted reproduced signal is resampled in a sampling pulse generating circuit (13) and a resampling circuit (7) which operates based on the above stated phase-locked loop circuit. As a result, the resampling circuit (7) provides an output having a considerably decreased amount of jitter.
17 Citations
11 Claims
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1. A jitter correction circuit comprising:
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analog-to-digital converting circuit converts an input reproduced compressed video signal to a digital signal based on an input clock pulse; a phase deviation detection circuit connected to said analog-to-digital converting circuit, said phase deviation detection circuit latches said digital signal and detects an amount of deviation of said digital signal, said phase deviation detection circuit producing a phase deviation; digital-to-analog converting circuit converts said phase deviation to an analog signal; a first low-pass filter connected to said digital-to-analog converting circuit, said first low-pass filter setting a cut-off frequency of said analog signal approximately equal to a horizontal synchronizing signal; a first control oscillation circuit receives said horizontal synchronized signal from said first low-pass filter and provides a first oscillation output having a rapid frequency response characteristic based on said phase deviation of said horizontal synchronized signal contained in said reproduced compressed video signal; a timing pulse generating circuit receives said first oscillation output from said first control oscillation circuit and produces said clock pulse input to said analog-to-digital converting circuit, wherein said analog-to-digital converting circuit samples said reproduced video signal based on said first oscillation output to provide said digital signal by analog-to-digital conversion; a second oscillation control circuit provides a second oscillation output having a stable frequency response characteristic based on at least one of a phase deviation of said horizontal synchronized signal and a phase deviation of said first oscillation output; and a resampling circuit resamples said digital signal from said analog-to-digital converting circuit based on said second oscillation output. - View Dependent Claims (2, 4, 6, 8, 10, 11)
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3. said second oscillation control circuit comprises a phase-locked loop circuit comprising:
- a phase comparing circuit for receiving as a reference input at least one of said first oscillation output and a frequency divided output thereof and receiving as an input to be compared, at least one of said second oscillation output feedback and a frequency divided output thereof;
a low-pass filter having a low cut-off frequency for receiving an output of said phase comparing circuit;
a limiter for limiting an output of said low-pass filter within a predetermined range; and
a variable oscillation circuit for receiving an output of said limiter as a control input. - View Dependent Claims (5, 7)
- a phase comparing circuit for receiving as a reference input at least one of said first oscillation output and a frequency divided output thereof and receiving as an input to be compared, at least one of said second oscillation output feedback and a frequency divided output thereof;
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9. A jitter correction circuit comprising:
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analog-to-digital converting circuit converts an input reproduced compressed video signal to a digital signal based on a first clock pulse input; a phase deviation detection circuit connected to said analog-to-digital converting circuit, said phase deviation detection circuit latches said digital signal and detects an amount of deviation of said digital signal, said phase deviation detection circuit producing a phase deviation; a digital-to-analog converting circuit converts said phase deviation to an analog signal; a low-pas filter connected to said digital-to-analog converter, said low-pass filter setting a cut-off frequency of said analog signal to a horizontal synchronized signal; a first oscillation control circuit receives said horizontal synchronized signal from said low-pass filter and provides a first oscillation output having a rapid frequency response characteristic based on said phase deviation of said horizontal synchronized signal contained in said reproduced compressed video signal; a timing pulse generating circuit receives said first oscillation output from said first oscillation control circuit and produces said first clock pulse input to said analog-to-digital converting circuit, wherein said analog-to-digital converting circuit samples said reproduced video signal based on said first oscillation output to provide said digital signal by analog-to-digital conversion; a second oscillation control circuit receives said first oscillation output as a reference input and provides a second clock having a stable frequency; a serial-to-parallel converting circuit converts said digital signal as serial data from said analog-to-digial converting circuit to parallel data based on said first clock pulse from said timing pulse generating circuit, said serial-to-parallel converting circuit including a latching means for latching said converted parallel digital data based on a frequency divided output of said first clock pulse; and a parallel-to-serial converting circuit latches an output of said latching means based on a frequency divided output of said second clock from said second oscillation control circuit, said parallel-to-serial converting circuit converting said parallel data to serial data based on said second clock.
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Specification