JPH0229277B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a dubbing device, and particularly to a rotating dubbing device.
It has two magnetic heads, a switching means for the two magnetic heads, and a switching signal generating means for outputting a magnetic head switching signal to the switching means, and reproduces by alternately switching the two magnetic heads. This invention relates to a dubbing device used when dubbing using a video tape recorder (hereinafter abbreviated as VTR), which has become popular in Japan.

(Prior art) Conventionally, when dubbing is performed by uneven concentration using a VTR configured as described above, generally two
Dubbing is performed by simply electrically connecting VTRs and driving them at the same time, and the signal transmission method in this case is that the composite video signal that is modulated and recorded by a modulation circuit during recording is not demodulated. There is also a system in which the data is transmitted as is to the recording side VTR and recorded on an unrecorded magnetic tape via a magnetic head.

However, the above-mentioned conventional method uses two rotating magnetic heads alternately to perform recording and reproduction.
Recording and playback in VTRs is generally performed using a helical scan method that eliminates the guard hand, but in order to prevent crosstalk between adjacent tracks, the track recorded by the first magnetic head contains a color signal. the phase of every horizontal period
Recording is performed by rotating while advancing by 90 degrees, and on the track recorded by the second magnetic head, the phase of the color signal is rotated and recorded while being delayed by 90 degrees every horizontal period. For this reason, there is a drawback that if the rotation direction of the phase of the color signal differs between the reproduction side VTR and the recording side VTR during dubbing, the color will not be reproduced normally when the dubbed magnetic tape is reproduced.

(Purpose) The present invention aims to eliminate the above-mentioned drawbacks of the conventional VTR, and provides a VTR capable of comparing the phases of the reproducing side VTR and the recording side VTR and correcting the phase shift as necessary. The present invention provides a dubbing device.

(Example) Hereinafter, the present invention will be described according to an example shown in the drawings. In FIG. 1, 1 is a reproduction side VTR, 2 is a first magnetic head, 3 is a second magnetic head, 4 is a switching circuit for switching between the first and second magnetic heads 2 and 3; 5 is a switching signal generation circuit that outputs a switching signal for the first and second magnetic heads 2 and 3 to the switching circuit 4; 6 is a recording side VTR; 7 is a first magnetic head; 8 is a second magnetic head. , 9 is the first
and a switching circuit for switching between the first and second magnetic heads 7 and 8; 10 is a switching signal generation circuit that outputs a switching signal for the first and second magnetic heads 7 and 8 to the switching circuit 9; second magnetic head 7,8
12 is a dubbing device, 13 is a playback VTR 1, and 12 is a dubbing device.
14 is a comparison circuit that compares the phase rotation direction of the color signals of the reproduction and recording VTRs 1 and 6; 15 is a comparison circuit that transmits the synchronization signal reproduced at the recording side to the recording side VTR 6;
This is a correction signal generation circuit that generates a correction signal based on the signal from the comparison circuit 15 when the phase rotation directions of the VTRs 1 and 6 are different.

Next, the operation of the above embodiment will be explained. In other words, the recorded magnetic tape is placed on the playback side VTR 1.
When an unrecorded magnetic tape is inserted into each of the recording side VTRs 6, and the reproducing side VTR 1 is driven in playback mode and the recording side VTR 6 is driven in recording mode at the same time,
On the reproduction and recording side VTRs 1 and 6, magnetic heads 2,
As the rotary head drum 3, 7, and 8 are mounted is rotated at high speed, a switching signal as shown in FIG. Sometimes, when the switching signal to the first magnetic head 2, 7 is off, reproduction and recording are performed while switching to the second magnetic head 3, 8, and the reproduction and recording side VTRs 1, 6
From there, phase information of the color signal is output to the comparator circuit 14. The comparator circuit 14 compares the phases of the reproducing and recording VTRs 1 and 6, and if the rotation directions of the phases are the same, the synchronization signal as shown in FIG. is input directly from the playback side VTR 1 to the control circuit 11 of the recording side VTR 6.
It controls the VTR 6.

However, when the direction of rotation of the phase of the color signal in the reproducing and recording VTRs 1 and 6 is different, a signal is output from the comparison circuit 14 to the correction signal generation circuit 15. This correction signal generation circuit 15 utilizes a switching signal generated by the reproduction side VTR 1 to switch between the first and second magnetic heads 2 and 3, as well as to control the rotation of the rotary head drum and synchronized with the synchronizing signal. The correction signal is output to the synchronization signal transmission circuit 13. By doing so, the playback side
The synchronization signal reproduced by the VTR 1 is added with a correction signal as shown in FIG. 1
Speed up the rotation and rotate the playback side VTR1 and the recording side VTR
6, the rotation direction of the phase of the color signal is made the same.

Therefore, in the above embodiment, it is possible to prevent the disadvantage that the rotation direction of the phase of the color signal is different between the reproduction side VTR and the recording side VTR during dubbing, and colors do not appear when the dubbed magnetic tape is reproduced. Can be done.

(Effects) As described above, the present invention includes two rotating magnetic heads, switching means for the two magnetic heads, and switching signal generating means for outputting a switching signal for the magnetic heads to the switching means. In a dubbing device for a video tape recorder that performs recording and playback by alternately switching the two magnetic heads, the phases of the color signals of the playback video tape recorder and the recording tape recorder are compared. a synchronizing signal transmitting means for transmitting a synchronizing signal generated by the reproducing video tape recorder to the controlling means of the recording video tape recorder, and a correction signal generating means for outputting a correction signal based on the output from the comparing means. and when the phases of the color signals of the playback side video tape recorder and the recording side videotape recorder are different, the correction signal is outputted by the correction signal generation means detected by the comparison means to match the phases. It is possible to prevent colors from disappearing when a dubbed magnetic tape is reproduced due to a difference in the phase rotation direction of the color signal between the reproduction side VTR and the recording side VTR during dubbing.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the device of the present invention, and FIG. 2 is a diagram of waveforms in the circuit in FIG. 1. 1... Playback side videotape recorder, 2, 7
...First magnetic head, 3, 8... Second magnetic head, 4, 9... Switching circuit, 5, 10... Switching signal generation circuit, 6... Recording side video tape recorder, 11... Control Circuit, 12...dubbing device,
13... Synchronous signal transmission circuit, 14... Comparison circuit,
15...Correction signal generation circuit.

Claims (1)

[Claims] 1. It has two rotating magnetic heads, and
A video recording device comprising means for switching between the two magnetic heads and a switching signal generating means for outputting a switching signal for the magnetic heads to the switching means, and recording and reproducing is performed by alternately switching between the two magnetic heads. A dubbing device for a tape recorder includes a comparison means for comparing the phases of color signals of a playback video tape recorder and a recording video tape recorder, and a comparison means for comparing the phases of color signals of a playback video tape recorder and a synchronization signal generated by the playback video tape recorder. A synchronizing signal transmission means for transmitting a synchronization signal to the control means of the recorder and a correction signal generation means for outputting a correction signal based on the output from the comparison means are provided, and the phase of the color signal between the playback video tape recorder and the recording video tape recorder is provided. 1. A dubbing device characterized in that, if the two signals are different, the comparison means detects the difference, and the correction signal generation means outputs a correction signal to match the phases.