Apparatus for measuring SC/H phase of composite video signal
AssigneeLeader Electronics Corporation
InventorMituyoshi Suzuki
Life of this patent
Estimating the term…
Abstract
A measuring instrument for SC/H phase of a composite video signal is provided in which a phase comparison is made between at least a portion of a color burst extracted from the video signal and a continuous subcarrier frequency signal that is phase-locked to the leading edge of the horizontal sync phase so as to determine the particular SC/H pulse. The instrument includes a display device which provides a display concerning the measured SC/H phase in the form of characters and/or a waveform.
Claims21
An SC/H phase measuring apparatus for measuring an SC/H phase of a composite video signal, comprising:
- a. burst extracting means connected to receive said composite video signal for extracting a subcarrier burst from said composite video signal to output the extracted subcarrier burst;
- b. oscillating means connected to receive said composite video signal for generating a horizontal sync phase-locked signal of a subcarrier frequency that is phase-locked to the leading edge of a horizontal sync pulse of said composite video signal;
- c. phase difference detecting means connected to receive said extracted subcarrier burst and said horizontal sync phase-locked signal for comparing a phase of said extracted subcarrier burst with a phase of said horizontal sync phase-locked signal to generate a phase difference signal representative of the phase difference therebetween;
- and
- d. display means connected to receive said phase difference signal for providing a display of the SC/H phase in response to said phase difference signal.
An SC/H phase measuring apparatus for measuring an SC/H phase of a composite video signal, comprising:
- a. burst extracting means connected to receive said composite video signal for extracting a subcarrier burst from said composite video signal to output the extracted subcarrier burst;
- b. oscillating means connected to receive said composite video signal for generating a pair of first and second horizontal sync phase-locked signals of a subcarrier frequency that is phase-locked to the leading edge of a horizontal sync pulse of said composite video signal, said second horizontal sync phase-locked signal being shifted in phase by 90.degree. from said first horizontal sync phase-locked signal;
- c. phase difference detecting means connected to receive said extracted subcarrier burst and said pair of first and second horizontal sync phase-locked signal for comparing a phase of said extracted subcarrier burst with phases of said pair of first and second horizontal sync phase-locked signals to generate a pair of first and second phase difference signals, said first phase difference signal being signal representative of the phase difference between said extracted subcarrier burst and said first horizontal sync phase-locked signal, and said second phase difference signal being a signal representative of the phase difference between said extracted subcarrier burst and said second horizontal sync phase-locked signal;
- and
- d. display means connected to receive said pair of first and second phase difference signals for providing a display of the SC/H phase in response to said pair of first and second phase difference signals.
A method for measuring an SC/H phase of a composite video signal, comprising the steps of:
- a. extracting a subcarrier burst from said composite video signal to output the extracted subcarrier burst;
- b. separating a horizontal sync pulse from said composite video signal;
- c. generating a horizontal sync phase-locked signal of a subcarrier frequency that is phase-locked to the leading edge of the horizontal sync pulse;
- d. comparing a phase of said extracted subcarrier burst with a phase of said horizontal sync phase-locked signal to generate a phase difference signal representative of the phase difference therebetween;
- and
- e. providing a display of the SC/H phase in response to said phase difference signal.
Dependencies are inferred from the claim text.