JPS6085468A - Recording and reproducing device of character multiplex broadcast - Google Patents

Abstract

PURPOSE:To enable recording and reproducing of character signals without giving influences on recording and reproducing of ordinary video signals by converting digital data of character signals in terms of time base and recording and reproducing by utilizing a guard band at the time of standard picture recording. CONSTITUTION:A video signal head A32, a video signal head B33, a character signal head A'35 and a character signal B'34 are arranged at intervals of 90 deg. on the circumference of a cylinder 30 of the picture recording head of a VTR. Digital data of separated character signals are inputted once to a data memory 3, and converted in terms of time base by reading slowly through a character signal recording system processing circuit 4, and recorded on a guard band by using the recording and reproducing head A'35 for character signals and the head B'34. The record of converted low-frequency character signals in terms of time base is delayed by physical positional relation on the cylinder 30 of the head A'35 and head B'34 based on a control signal 16 used in recording ordinary video signals, and recorded in tracks 23, 24 and tracks 25, 26 which are nearly at the center of the guard band.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for recording and reproducing teletext broadcasting.

In teletext broadcasting, the character signal is 1 in the odd-numbered field of the television video signal (the field is called H).
In the 6th H, 21st H, and even fields, the 279th H and 284th H are multiplexed. This character signal is a digital data signal that is multiplexed in the form of pulses, and the bit rate for data transmission is set to a television standard or an acceptable data rate. However, the frequency that can be recorded with current video tape recorders (hereinafter referred to as VTR) is approximately 4.5 MHz or less, and there are many jitters and the like. For this reason, it has been difficult to record and reproduce character signals while the character signals remain present during the vertical retrace period.

SUMMARY OF THE INVENTION An object of the present invention is to provide a teletext recording/playback device that enables recording/playback of text signals without affecting the recording/playback of normal video signals.

SUMMARY OF THE INVENTION The object of the present invention is to provide a teletext recording/playback device capable of recording and reproducing text signals of teletext broadcasts at a low frequency on a standard recording guard band of a VTR.

FIG. 1 shows an embodiment of the present invention, in which 1 is a television video signal separation circuit, 3 is a data memory, 4 is a character signal recording processing circuit, 5 is a luminance signal recording system signal processing circuit, and 6 is a color signal signal processing circuit. 1 is a recording system signal processing circuit, 7 is a tape head system recording and reproducing device, 8 is a luminance signal reproduction system signal processing circuit, 9 is a color signal reproduction system signal processing circuit, 10 is a character signal reproduction processing circuit, 1
1 is a data memory, 12 is a transmission signal processing circuit, 13 is a character signal superimposing circuit, and 14 is a reproduced television picture image signal.

A television video signal 1 containing a character signal from teletext broadcasting within a vertical synchronization retrace period is separated from a normal video signal by a character signal separation circuit 2, and the video signal is separated from a normal video signal by a luminance signal recording system signal processing circuit. 5 and a color signal recording system signal processing circuit 6, normal standard recording is performed. As shown in Fig. 3, the recording head of a VTR has video signal heads A32, video signal heads B33, character signal heads A'35, and character signal B'34 arranged at 90' intervals around a cylindrical cylinder 30. is used. At this time, as the recording head, the standard recording 3x mode 6H mode head (head A32, head B53) is used to record, and a guard band is created between the recording tracks (second track 17.
18 and tracks 19° and 20, and tracks 19.20 and 21.22)
.

On the other hand, the digital data of the separated character signal is once input to the data memory 3, and is slowly read out through the character signal recording system processing circuit 4, where it is converted into the time axis and converted into the character signal recording and reproducing head A'. 35. Head B'
34 on the guardband. The recording of this time-base converted low-frequency character signal is performed based on the physical positional relationship on the cylinder 30 of the head A'35 and head B'34, based on the control signal 16 normally used for recording the video signal. ) and recorded on tracks 23.24 and 25.26 approximately in the center of the guard band.

Next, regarding reproduction, recording/reproducing head A32, head B
33, track 17.18 and track 19.2
0 and tracks 21 and 22, a normal video signal is reproduced via the luminance signal reproduction processing circuit 8 and the color signal reproduction system processing circuit 9. On the other hand, the character signal recorded after low frequency conversion is recorded on tracks 23 and 24 on the cigar band by the recording/reproducing head A'35 and head B/34.
and tracks 25 and 26, are once input into the data memory through the character signal reproduction system processing circuit 10, read out at high speed through the transmission signal processing circuit 12, time axis converted, and converted back to the original character signal. is output. Thereafter, the character signal read out at high speed is superimposed on the vertical synchronization blanking period of the normal video signal reproduced by the character signal superimposition circuit 13, and the reproduction is equivalent to the TV program video signal 1 of normal teletext broadcasting. A television video signal 14 is output. For this reproduction, head N35° head B is used as a reference for the control signal 16 used for normal video signal reproduction.
'34 on cylinder 30, tracks 23, 24 and 25 .
26 is traced and reproduced.

Therefore, the recording and playback of text signals for teletext broadcasting, which has been considered difficult in the past, is now possible by recording text signals whose time axis has been converted by using a guard band in standard recording mode.
You can do it if you want to regenerate it.

As described above, the digital data of the text signal of teletext broadcasting can be time-axis converted, recorded and played back using the guard band that occurs during standard recording, and the played back digital data can be converted into a normal playback video signal. Since the teletext broadcasts recorded on this device are output in a superimposed manner, the teletext broadcasts recorded on this device can be played back by this device and input to a TV for teletext broadcasts in the same way as when receiving normal teletext broadcasts. You can enjoy the screen. Also, the use of guard bands makes effective use of tape.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a recording/playback device according to an embodiment of the present invention, FIG. 2 is a diagram showing a recording state of a VTR tape used in the recording/playback device according to an embodiment of the present invention, and FIG. 3 is a block diagram of a recording/playback device according to an embodiment of the present invention. FIG. 2 is a top view of a cylinder head to be used in a recording/playback device according to an embodiment of the present invention. 1...Television video signal, 2...
Character signal separation circuit, 3...Data memory, 4
...Character signal recording system processing circuit, ...Brightness signal recording system signal processing circuit, 6 ...Color signal recording system signal processing circuit, 7 ...Tape , head system recording/reproducing device, 8... luminance signal reproduction system signal processing circuit, 9... color signal reproduction system signal processing circuit, 10...
... Character signal reproduction system processing circuit, 11 ... Data memory, 12 ... Sending signal processing circuit, 13
....Character signal superimposition circuit, 14..Reproduction television video signal, 15..Video and character signal recording section, 16.. River/control track, 1
7-22... Normal video signal recording track, 23
~26...Low frequency conversion character signal track, 27.
...Head running direction, 28...Tape running direction, 29...Audio track, 30...Mark...
Cylinder, 31... River/Cylinder center. 530

Claims (1)

[Scope of Claims] A converting means for converting, a character signal recording means for recording the output of the converting means between Eirin signal recording tracks of a recording tape,
a character signal recording and reproducing means for reading character signals from the recording tape; and writing the character signal reproduction output read from the character signal reproducing means (a rare memory; and a high-speed memory for reading the character signal reproduction output from the memory at high speed); A teletext broadcasting recording and reproducing device equipped with a readout means and a disconnector.