Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1998-10-13
2002-05-21
Christensen, Andrew B. (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000, C348S705000
Reexamination Certificate
active
06393194
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an apparatus for recording and reproducing a video signal on and from a magnetic tape.
2. Description of the Related Art
Some video tape recorders (VTR's) are based on a standard format referred to as a VHS format. There is an S-VHS format which improves over the VHS format. A VTR of the S-VHS standard can record and reproduce a video signal which is wider in frequency band and higher in picture quality than a video signal handled by a VTR of the VHS standard.
The VTR of the S-VHS standard uses an exclusive magnetic tape referred to as an S-VHS tape. The S-VHS tape is designed to more suit with a video signal having a wide frequency band and short wavelengths in comparison with a VHS tape.
In the VTR of the VHS standard, a video signal to be recorded is separated into luminance and chrominance signals. The luminance signal is converted or modulated into an FM modulated luminance signal having a frequency deviation of 3.4 to 4.4 MHz.
The chrominance signals are down-converted into a low frequency band around 629 kHz. The FM modulated luminance signal and the frequency-down-converted chrominance signals are combined before being recorded on a VHS tape.
In the VTR of the S-VHS standard, a video signal to be recorded is separated into luminance and chrominance signals. The luminance signal is converted into an FM modulated luminance signal having a frequency deviation of 5.4 to 7.0 MHz. The chrominance signals are down-converted into a low frequency band around 629 kHz. The FM modulated luminance signal and the frequency-down-converted chrominance signals are combined before being recorded on an S-VHS tape.
The VTR of the VHS standard can use an S-VHS tape instead of a VHS tape. In general, the VTR of the S-VHS standard can operate in each of two different modes, a VHS mode and an S-VHS mode. During the VHS mode of operation of the S-VHS VTR, a video signal of the VHS format is recorded on a VHS tape or an S-VHS tape. During the S-VHS mode of operation of the S-VHS VTR, a video signal of the S-VHS format is recorded on an S-VHS tape.
In general, an S-VHS tape is contained in a cassette having an identification hole which indicates that the tape therein is of the S-VHS type. The VTR of the S-VHS standard has a function of sensing an identification hole in a tape cassette placed therein. When the S-VHS VTR senses an identification hole in a tape cassette, the S-VHS mode of operation is automatically started. On the other hand, when the S-VHS VTR fails to sense an identification hole in a tape cassette, the VHS mode of operation is started.
An advanced VTR detects characteristics of a used magnetic tape, and records a video signal on the magnetic tape under recording conditions (that is, the VHS mode or the S-VHS mode) determined in response to the detected tape characteristics. The advanced VTR can optimize signal recording tape by tape.
Specifically, the advanced VTR implements a preliminary process before the recording of a video signal. During the preliminary process, the advanced VTR records and reproduces a test signal on and from a used magnetic tape. The advanced VTR detects characteristics of the magnetic tape (that is, the VHS tape or the S-VHS tape) from the reproduced test signal. Then, the advanced VTR records a video signal on the magnetic tape under recording conditions determined in response to the detected tape (the VHS tape or the S-VHS tape) characteristics.
As previously explained, the S-VHS VTR operates in the VHS mode when a VHS tape is used. Some VHS tapes have improved characteristics sufficient to store wide-band and high-quality video signals. In general, S-VHS tapes are higher in price than VHS tapes.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a magnetic recording and reproducing apparatus which can record and reproduce a wide-band and high-quality video signal on and from an inexpensive magnetic tape such as a VHS tape.
A first aspect of this invention provides a magnetic recording and reproducing apparatus comprising first means for recording a video signal of a high-quality format, which has a first given frequency band, on a standard magnetic tape designed to record a video signal of a standard format having a second given frequency band narrower than the first given frequency band; and second means for reproducing a video signal of the high-quality format from a standard magnetic tape.
A second aspect of this invention provides a magnetic recording and reproducing apparatus comprising first means for recording a video signal of a first standard format, which has a first given frequency band, on a magnetic tape of a first standard type designed to record a video signal of the first standard format;
second means for recording a video signal of a second standard format, which has a second given frequency band wider than the first given frequency band, on a magnetic tape of a second standard type designed to record a video signal of the second standard format; third means for recording a video signal of a high-quality format, which has a third frequency band wider than the first frequency band, on a magnetic tape of the first standard type; fourth means for reproducing a video signal of the first standard format from a magnetic tape of the first standard type; fifth means for reproducing a video signal of the second standard format from a magnetic tape of the second standard type; and sixth means for reproducing a video signal of the high-quality format from a magnetic tape of the first standard type.
A third aspect of this invention is based on the first aspect thereof, and provides a magnetic recording and reproducing apparatus further comprising third means for detecting whether or not the video signal reproduced by the second means is of the high-quality format.
A fourth aspect of this invention is based on the third aspect thereof, and provides a magnetic recording and reproducing apparatus further comprising fourth means for detecting whether a tape-type identification hole is present in or absent from a housing of the standard magnetic tape accessed by the second means; fifth means for detecting a frequency band of the video signal reproduced by the second means; and sixth means for detecting whether or not the video signal reproduced by the second means is of the high-quality format in response to a result of the detection by the fourth means and the frequency band detected by the fifth means.
A fifth aspect of this invention is based on the third aspect thereof, and provides a magnetic recording and reproducing apparatus further comprising a reproducing FM equalizer for processing the video signal reproduced by the second means; a de-emphasis circuit for processing the video signal reproduced by the second means; a noise canceller for processing the video signal reproduced by the second means; and fourth means for controlling a signal processing characteristic of at least one of the reproducing FM equalizer, the de-emphasis circuit, and the noise canceller in response to a result of the detection by the third means.
A sixth aspect of this invention provides a magnetic recording and reproducing apparatus comprising first means for processing an input video signal into a processing-resultant video signal having a first given frequency band; second means for recording the processing-resultant video signal, which is generated by the first means, on a standard magnetic tape designed to record a standard-format video signal having a second given frequency band narrower than the first given frequency band; third means for reproducing a video signal having the first given frequency band from a standard magnetic tape; and fourth means for recovering an original video signal from the video signal reproduced by the third means.
A seventh aspect of this invention provides a magnetic recording and reproducing apparatus comprising first means for processing an input video signal into one among a video signal of a first standard format having a first
Matsuo Yasutoshi
Mikami Seiichi
Chieu Po-lin
Christensen Andrew B.
Victor Company of Japan Ltd.
Woo Louis
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