Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1998-09-22
2003-02-11
Tran, Thai (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000
Reexamination Certificate
active
06519409
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an apparatus for recording a video signal on 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 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 or modulated 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 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 standard 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 standard 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 apparatus which can record a wide-band and high-quality video signal on an inexpensive magnetic tape such as a VHS tape.
A first aspect of this invention provides a magnetic recording apparatus comprising first means for processing an input video signal into a processing-resultant video signal having a first given frequency band; and second means for recording the processing-resultant video signal, which is generated by the first means, on a standard magnetic tape which is designed to record a standard-format video signal having a second given frequency band narrower than the first given frequency band.
A second aspect of this invention provides a magnetic recording apparatus comprising first means for processing an input video signal into one among a first standard-format video signal having a first given frequency band, a second standard-format video signal having a second given frequency band wider than the first given frequency band, and a processing-resultant video signal having a third given frequency band wider than the first given frequency band; second means for recording the first standard-format video signal, which is generated by the first means, on a first standard magnetic tape which is designed to record a first standard-format video signal; third means for recording the second standard-format video signal, which is generated by the first means, on a second standard magnetic tape which is designed to record a second standard-format video signal; and fourth means for recording the processing-resultant video signal, which is generated by the first means, on the first standard magnetic tape.
A third aspect of this invention is based on the second aspect thereof, and provides a magnetic recording apparatus further comprising fifth means for, in response to user's request, deciding which of the first, second, and third standard-format video signals the first means processes the input video signal into; and sixth means for recording the video signal, which is decided by the fifth means, on a magnetic tape.
A fourth aspect of this invention is based on the second aspect thereof, and provides a magnetic recording apparatus wherein the processing-resultant video signal can be reproduced from the first standard magnetic tape by a magnetic reproducing apparatus for a second standard-format video signal and a second standard magnetic tape.
A fifth aspect of this invention is based on the second aspect thereof, and provides a magnetic recording apparatus further comprising fifth means for detecting whether or not the first standard magnetic tape is suited to recording of the process-resultant video signal.
A sixth aspect of this invention is based on the fifth aspect thereof, and provides a magnetic recording apparatus wherein the fifth means comprises sixth means for recording a test signal to the first standard magnetic tape; seventh means for reproducing the test signal from the first standard magnetic tape; and eighth means for detecting whether or not the first standard magnetic tape is suited to recording of the process-resultant video signal in response to a level of the reproduced test signal.
A seventh aspect of this invention is based on the sixth aspect thereof, and provides a magnetic recording apparatus wherein a recording level of the test signal is equal to a recording level of the process-resultant video signal.
An eighth aspect of this invention is based on the seventh aspect thereof, and provides a magnetic recording apparatus wherein the sixth means records the test signal at only a single recording level.
A ninth aspect of this invention is based on the seventh aspect thereof, and provides a magnetic recording apparatus wherein the sixth means records the test signal at a plurality of different recording levels, and the fourth means records the processing-resultant video signal at a recording level equal to a recording level among the plurality of the different recording levels at which a reproduction level is maximized.
A tenth aspect of this invention is based on the sixth aspect thereof, and provides a magnetic recording apparatus wherein the first means comprises a detail enhancer, a pre-emphasis circuit, a white/dark clip circuit, and a recording current equalizer,
Tran Thai
Victor Company of Japan Ltd.
Woo Louis
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