US 4,613,912 AGranted

Recording and reproducing apparatus for a video tape recorder

AssigneeHitachi, Ltd.

InventorsAkira Shibata, Atsushi Yoshioka, Katsuyuki Watanabe

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Abstract

In a video tape recorder of the two-head helical scan system, a wrap angle of a magnetic tape around a rotary head mechanism is set to more than 180.degree., e.g. about 220.degree., and an overlap recording section is provided in a recording track. A time compressed audio signal and a pilot signal for the tracking control are recorded in the overlap recording section. A frequency modulated luminance signal, low-frequency converted carrier color signal, frequency modulated audio signal, and pilot signal are mixed, and this mixed signal is recorded in another section of the recording track. Regulator means is provided to conjointly set the recording current levels of the low-frequency converted carrier color signal, frequency modulated audio signal, and pilot signal which are mixed to the frequency modulated luminance signal and recorded. The recording current levels of the time compressed audio signal and the frequency modulated luminance signal are respectively and individually set. When different kinds of magnetic tapes (e.g. metal powder tape and metal evaporated tape) are used, a level switching circuit is provided to switch the recording level of the signal of which the low-frequency converted carrier color signal, frequency modulated audio signal and pilot signal were mixed in accordance with the kinds of tapes.

Claims15

Dependent claims

A recording and reproducing apparatus for video and audio signals having two magnetic heads disposed on opposite sides by 180 degrees of the rotation angle on a head rotation mechanism to form slanted recording tracks on a magnetic tape during a recording operation and for tracing the tracks during a reproducing operation, including:

means for wrapping and guiding the magnetic tape around said head rotation mechanism at larger than 180 degrees of the rotation angle so as to form a main track and an additional track, said additional track being formed in a period when said two magnetic heads simultaneously trace on said magnetic tape;
means for recording a time compressed audio signal on said additional track;
and
means for recording a video signal on said main track;
wherein said apparatus comprises:
means for compressing an input audio signal into a time compressed audio signal;
means for extracting a luminance signal and a carrier color signal from an inputted video signal;
modulation means for frequency modulating a carrier signal with said extracted luminance signal to produce a frequency modulation luminance signal;
means for converting the frequency of said extracted carrier color signal into another frequency lower than the frequency of said frequency modulation luminance signal to produce a lower frequency conversion carrier color signal;
means for generating a pilot signal having a frequency lower than the frequency of said lower frequency conversion carrier color signal, said pilot signal being used for control of tracking of the recording tracks during the reproducing operation;
means for recording on said main track, by said two magnetic heads, a first mixing signal produced by mixing said frequency modulation luminance signal, said lower frequency conversion carrier color signal and said pilot signal;
means for recording on said additional track, by said two magnetic heads, a second mixing signal produced by mixing said time compressed audio signal with said pilot signal, the time period of said time compressed audio signal being no longer than the period of said additional track;
and
means for simultaneously supplying the same pilot signals to said two magnetic heads during recording on said additional track, said pilot signal recorded on the additional track being the same as the pilot signal recorded on the main track.

11 more elements

A recording and reproducing apparatus for video and audio signals having two magnetic heads disposed on opposite sides by 180 degrees of the rotation angle on a head rotation mechanims to form slanted recording tracks on a magnetic tape during a recording operation and for tracing the tracks during a reproducing operation, including:

means for wrapping and guiding the magnetic tape around said rotation mechanism at larger than 180 degrees of the rotation angle so as to form a main track and an additional track, said additional track being formed in a period when said two magnetic heads simultaneously trace on said magnetic tape;
means for recording a time compressed audio signal on said additional track;
and
means for recording a video signal on said main track;
wherein said apparatus comprises:
means for extracting a luminance signal and a carrier color signal from an inputted video signal;
modulation means for frequency modulating a carrier signal with said extracted luminance signal to produce a frequency modulation luminance signal;
means for converting the frequency of said extracted carrier color signal into another frequency lower than the frequency of said frequency modulation luminance signal to produce a lower frequency conversion carrier color signal;
means for compressing an input audio signal into a time compressed audio signal, the time period of said time compressed audio signal being no longer than the period of said additional track.
means for converting said time compressed audio signal into a pulse code modulation (PCM, signal:
means for converting an input audio signal which is simultaneously input together with the inputted video signal into a frequency modulated audio signal;
means for generating a pilot signal for controlling tracking during a reproducing operation;
means for mixing said lower frequency conversion carrier color signal, said frequency modulated audio signal and said pilot signal;
two first and second switches for respectively switching said PCM audio signal and said frequency modulated luminance signal in the periods of the main track and additional track, and for outputting said switched signal;
two third and fourth switches for respectively switching the output of said mixing means and said pilot signal in the periods of the main track and additional track, and for outputting said switched signal;
means for adding the output signals of said first and third switches, and for supplying the added output to one of said magnetic heads;
and
means for adding the output signals of said second and fourth switches, and for supplying the added output to the other of said magnetic heads.

15 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/530,628Filed 9 Sep 1983
Priority: JP 57-15660210 Sep 1982
Granted: 23 Sep 1986
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

H04N 9/793
Processing of colour television signals in connection with recording: for controlling the level of the chrominance signal, e.g. by means of…
H04N 9/79
Details of colour television systems: processing of colour television signals in connection with recording
H04N 9/7921
Processing of colour television signals in connection with recording: for more than one processing mode
H04N 9/7933
For controlling the level of the chrominance signal, e.g. by means of automatic chroma control circuits: the level control being frequency-dependent