Jitter correction system

Claim 2

A video signal jitter correction system comprising means for supplying a reference horizontal synchronizing signal, phase modulating means for modulating said reference horizontal synchronizing signal as supplied from said supplying means, means comprising an input terminal having a video signal applied thereto, said video signal including jitter components of relatively high frequency and relatively low frequency, means for separating a horizontal synchronizing signal from the video signal supplied through the input terminal, phase comparing means for comparing the phase of the modulated reference horizontal synchronizing signal supplied from said phase modulating means with the phase of the horizontal synchronizing signal supplied from the synchronizing signal separation means, said phase comparing means producing an error signal responsive to the jitter component, low-pass filter means for taking out a jitter component of relatively low frequency from the output signal of the phase comparing means, said low-pass filter means supplying the taken out low frequency jitter component to said phase modulating means, said phase modulating means modulating said reference horizontal synchronizing signal with said low frequency jitter component, high-pass filter means for taking out a jitter component of relatively high frequency from the output signal of the phase comparing means, and means responsive to the high frequency jitter component supplied from said high-pass filter means for correcting the high frequency jitter component included in the video signal supplied through said input terminal.

Claim 3

The system of claim 1 and a video tape recorder, said video signal having the jitter components being a signal reproduced from magnetic tape by said video tape recorder, said reference horizontal synchronizing signal supplying means including an input terminal having a reference video signal applied thereto, and means for separating the horizontal synchronizing signal from the reference video signal.

Claim 4

The system of claim 1 in which the frequency of said jitter component of relatively low frequency is less than approximately 10 Hz and the frequency of said jitter component of relatively high frequency is more than approximately 10 Hz.

Claim 5

A jitter correction system comprising a first input terminal having a reference video signal applied thereto, a first separating means for separating a reference horizontal synchronizing signal from the reference video signal, phase modulating means for modulating said reference horizontal synchronizing signal, means responsive to the modulated reference horizontal synchronizing signal for generating a comparison waveform, a second input terminal having applied thereto a video signal reproduced from a magnetic tape in a video tape recorder, said reproduced video signal including jitter components of relatively high frequency and relatively low frequency, second separating means for separating a horizontal synchronizing signal from the reproduced video signal, means responsive to the horizOntal synchronizing signal supplied from said second separating means for generating a sampling pulse, sampling means for sampling the comparison waveform supplied from said comparison waveform generating means with the sampling pulse supplied from said sampling pulse generating means, said sampling means producing an error signal responsive to the jitter component, low-pass filter means for taking out a jitter component of relatively low frequency from the output signal of the phase comparing means, said low-pass filter means supplying the taken out low frequency jitter component to said phase modulating means, said phase modulating means modulating said reference horizontal synchronizing signal with said low frequency jitter component, high-pass filter means for taking out a jitter component of relatively high frequency from the output signal of the phase comparing means, and means for correcting the high frequency jitter component included in the video signal supplied through said second input terminal responsive to the high frequency jitter component supplied from said high-pass filter means.

Claim 6

A jitter correction system comprising a first input terminal having a reference video signal applied thereto, a first separating means for separating a reference horizontal synchronizing signal from the reference video signal, phase modulating means for modulating said reference horizontal synchronizing signal, means responsive to the modulated reference horizontal synchronizing signal for generating a comparison waveform, a second input terminal having applied thereto a video signal reproduced from a magnetic tape in a video tape recorder, said reproduced video signal including jitter components of relatively high frequency and relatively low frequency, second separating means for separating a horizontal synchronizing signal from the reproduced video signal, means responsive to the horizOntal synchronizing signal supplied from said second separating means for generating a sampling pulse, sampling means for sampling the comparison waveform supplied from said comparison waveform generating means with the sampling pulse supplied from said sampling pulse generating means, said sampling means producing an error signal responsive to the jitter component, low-pass filter means for taking out a jitter component of relatively low frequency from the output signal of the phase comparing means, said low-pass filter means supplying the taken out low frequency jitter component to said phase modulating means, said phase modulating means modulating said reference horizontal synchronizing signal with said low frequency jitter component, high-pass filter means for taking out a jitter component of relatively high frequency from the output signal of the phase comparing means, and means for correcting the high frequency jitter component included in the video signal supplied through said second input terminal responsive to the high frequency jitter component supplied from said high-pass filter means.

Claim 7

The system of claim 4 in which said phase modulating means includes means responsive to the reference horizontal synchronizing signal for generating a reference saw tooth wave having a frequency with a period equal to one horizontal scanning line period, means responsive to the signal supplied from the low-pass filter means for phase modulating the saw tooth wave, means responsive to the output of the phase modulating means for forming a pulse having a jitter component, said phase comparing means including means responsive to the pulse signal supplied from the pulse forming means for generating a saw tooth wave, means responsive to the horizontal synchronizing signal supplied from the synchronizing signal separation means for generating a sampling pulse, and phase detecting means for sampling the saw tooth wave supplied from the generating means in response to the sampling pulse, said signal supplied to the phase modulating means being an error signal formed responsive to the jitter component of relatively low frequency.

Claim 8

The system of claim 4 in which said video signal is reproduced from the magnetic tape in the video tape recorder by two rotary magnetic head rotating at 30 rotations per second, and said high-pass filter means has characteristics which are corrected to have an amplitude of substantially O dB and a phase difference of 0* at frequencies of 30 Hz and 60 Hz as compared with an amplitude and phase in the frequencies higher than nearly 300 Hz.