Video signal recording and reproducing apparatus using an added specific signal during recording

• US 5,321,518 A
• Filed: 06/03/1992
• Issued: 06/14/1994
• Est. Priority Date: 06/07/1991
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Hamamoto, Yasuo, Mita, Hideaki, Ochi, Atsuo
• Primary Examiner(s): Brier, Jeffery
• Assistant Examiner(s): Truong, Khoi
• Application Number:
  US07/893,009
• Time in Patent Office: 741 Days
• Field of Search: 358/327, 358/310, 358/320, 358/323, 358/335, 358/330, 358/318, 358/21 R, 358/160, 360/23, 360/33.1
• US Class Current: 386/308
• CPC Class Codes: H04N 5/923 using preemphasis of the signal before modulation and deemphasis of the signal after demodulation volume compression or expansion in amplifiers in general H03G7/00
• CPC Class Codes: H04N 9/81 the individual colour picture signal components being recorded sequentially only

Abstract

In a video signal recording/reproducing apparatus for emphasizing an input video signal, recording by adding an additional signal necessary for recording, and de-emphasizing when reproducing, the emphasis processing is stopped on the time axis in a period in which the additional signal is to be added. Besides, by adding an additional signal before emphasis processing, the waveform deterioration in the end portion of the effective period occurring due to the addition of additional signal after emphasis processing is decreased, and a favorable waveform reproduction is realized over the entire period of the effective portions.

Claims

1. A video signal recording and reproducing apparatus comprising:

a first signal adding means for adding a first specific signal in a synchronous signal period and a luminance/chrominance guard period of an input video signal, the input video signal having the synchronous signal period in which a synchronous signal is present, a first effective period in which a time-compressed chrominance signal is present, a second effective period in which a time-compressed luminance signal is present and the luminance/chrominance guard period between the first effective period and the second effective period;

an emphasis means for emphasizing an output video signal from said first signal adding means to obtain an emphasized video signal, said emphasized video signal having an impulse response period;

a second signal adding means for adding a second specific signal necessary for recording the video signal to the emphasized video signal in the synchronous signal period and the luminance/chrominance guard period to obtain a recordable video signal;

a recording and reproducing means for recording the recordable video signal on a recording medium and for reproducing the recorded video signal from the recording medium to obtain a reproduced emphasized video signal; and

a de-emphasis means for de-emphasizing the reproduced emphasized video signal to obtain a reproduced video signal;

wherein the first specific signal is, in the synchronous signal period, a black level signal which has a longer period than the impulse response period from a trailing end of the luminance signal and a colorless level signal which has a longer period than the impulse response period to a leading end of the chrominance signal, and is, in the luminance/chrominance guard period, a signal which becomes a predetermined luminance/chrominance guard signal after the second specific signal is added.

2. A video signal recording and reproducing apparatus comprising:

a time-division multiplexing means for time-compressing and time-division multiplexing input luminance and chrominance signals of a video signal to obtain a time-division multiplexed signal which has a synchronous signal period in which a synchronous signal is present, a first effective period in which a time-compressed chrominance signal is present, a second effective period in which a time-compressed luminance signal is present, and a luminance/chrominance guard period between the first effective period and the second effective period;

a first signal adding means for adding a first specific signal to the time-division multiplexed signal in the synchronous signal period and the luminance/chrominance guard period;

an emphasis means for emphasizing an output signal from said first signal adding means to obtain an emphasized signal, said emphasized signal having an impulse response period;

a second signal adding means for adding a second specific signal necessary for recording the emphasized signal to the emphasized signal in the synchronous signal period and the luminance/chrominance guard period;

a recording signal processing means for processing an output signal from said second signal adding means to obtain a recordable signal;

a recording and reproducing means for recording the recordable signal on a recording medium and for reproducing the recorded signal from the recording medium;

a reproduced signal processing means for processing a reproduced signal from said recording and reproducing means to obtain a reproduced emphasized signal;

a de-emphasis means for de-emphasizing the reproduced emphasized signal to obtain a reproduced time-division multiplexed signal; and

a time-division de-multiplexing means for de-multiplexing the reproduced time-division multiplexed signal to obtain reproduced luminance and chrominance signals;

wherein the first specific signal is, in the synchronous signal period, a black level signal which has a longer period than the impulse response period from a trailing end of the luminance signal and a colorless level signal which has a longer period than the impulse response period to a leading end of the chrominance signal, and is, in the luminance/chrominance guard period, a signal which becomes a predetermined luminance/chrominance guard signal after the second specific signal is added.