JPH04137268A - Recording and reproduction system for digital data of video tape recorder - Google Patents

Abstract

PURPOSE:To reproduce correct digital data even if a video tape extends or shrinks by converting digital values 0 and 1 of digital data into N-bit data, converting them into corresponding pulses, superposing the pulses on a video signal and recording them on e video tape. CONSTITUTION:A N-bit, e.g. 8-bit data reproducing circuit 1 converts the digital values 0 and 1 of the digital data showing information to be added to the video signal into 8-bit data to generate a data signal 101, and a D/A converter 2 converts it into the pulses to obtain a pulse signal 102. A superposing means 3 superposes the pulse signal 102 upon the video signal and records them on the video tape 5. A signal read out by a read head 6 is separated by a separating means 7 into the video signal and playback pulse signal 104 to generate an 8-bit data signal 107, from which the digital data are reproduced. Consequently, the digital data can accurately be reproduced without being affected by the extension and shrinkage of the video tape 5.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is directed to superimposing digital data indicating additional information of a video signal onto a video signal and recording it on a video tape, and superimposing the video tape onto the video signal. This invention relates to a digital data recording/playback method in a video tape recorder that plays back recorded digital data.

(Prior Art) The digital data recording and reproducing system in a conventional video recorder (VTR) has a formal configuration as shown in FIG. FIG. 4 shows the operation of the digital data recording and reproducing system in this conventional VTR. The recording and reproducing method of digital data in a conventional VTR will be explained with reference to FIG. The digital data is input to the pulse signal generating means 31, and the data 0 is converted into a pulse with an amplitude of QV, and the data 1 is converted into a pulse with an amplitude of 0.7V, resulting in a pulse signal 301. Above pulse signal 3
The generation of 01 is shown in FIG. 4(a).

This pulse signal 301 is input to a superimposing means 32 where it is superimposed on the video signal, and recorded as a superimposed signal 302 on a video tape 34 by a writing head 33. The operation described above is an operation of recording digital data indicating additional information of a video signal. Next, the playback operation will be explained. The superimposed signal 302 recorded on the video tape 34 is read out by the read head 35, and the read out superimposed signal 302
is separated into a video signal and a reproduction pulse signal 303 by the separating means 36. The sampling signal generation means 37 receives the reproduced pulse signal 303 and generates a sampling signal 304 based on a constant delay time t from the horizontal synchronizing signal (H-3YLC) included in the reproduced pulse code 303. The reproduction means 38 inputs the reproduction pulse signal 303 and the sampling signal 304, samples the reproduction pulse signal 303 with the sampling signal 304, and outputs reproduction digital data. The reproduction operation of this digital data is shown in FIG. 4(b). As is clear from FIG. 4, digital data "1010011" is being reproduced.

In addition to this, the conventional VTR digital data recording/reproducing method is to record binary digital data with an amplitude of 0.
Convert it into a pulse signal consisting of pulses of v and amplitude AV (Af-o), superimpose it on a video signal, and record it on a video tape,
The signal read from the video tape is separated into a video signal and a reproduction pulse signal, a sampling signal is obtained from a horizontal synchronizing signal included in the reproduction pulse signal, and the reproduction pulse signal is sampled with the sampling signal to reproduce digital data. was.

(Problems to be Solved by the Invention) Since video tape expands and contracts due to temperature differences, a change occurs in the read speed when reading a superimposed signal consisting of a video signal and a pulse signal from the video tape. Therefore, the time relationship between the horizontal synchronizing signal and each pulse in the reproduction pulse signal changes depending on the expansion and contraction of the video tape. On the other hand, since the sampling signal is generated based on a certain delay time t from the horizontal synchronization signal included in the reproduction pulse signal, the time relationship between the horizontal synchronization signal in the reproduction pulse signal and the sampling signal is It is always constant regardless of the expansion and contraction of. If there is no expansion or contraction on the videotape when recording and reproducing digital data, the sampling signal will sample the reproduction pulse signal at the correct timing as shown in Figure 5(b), so the correct data will be reproduced as the reproduction digital data. Ru. However, if the length of the videotape is longer during playback than during recording, then as shown in Figure 5(c).
As shown in the figure, the sampling timing of the sampling signal precedes the reproduction pulse signal, and the data is no longer reproduced. Also, if the videotape is shrunk during playback compared to when it was recorded, then
), the sampling timing of the sampling signal lags behind the reproduction pulse signal, and new data is no longer reproduced. In this way, conventional VT
The digital data recording and reproducing system in R had problems that needed to be solved.

SUMMARY OF THE INVENTION An object of the present invention is to provide a digital data recording and reproducing method in a video tape recorder that reproduces correct digital data even if the video tape is expanded or contracted.

(Means for Solving the Problems) The digital data recording/playback method in the video tape recorder of the present invention records a video signal and digital data indicating additional information of the video signal on a video tape in a superimposed manner. Digital data recording/playback method in a video tape recorder that plays back the video signal and digital data superimposed on a video tape. At the same time, the digital value 1 of the digital data is converted into second N-bit data having a different value from the first N-bit data, and the first and second N-bit data are converted into N-bit data on a time axis. means for generating an N-bit data signal arranged in series on the top; converting each N-bit data in the N-bit data signal into a pulse having an amplitude corresponding to its value; and producing a pulse signal by connecting these pulses on a time axis; means for generating the pulse signal and the video signal; means for recording the superimposed signal on a video tape; and means for reading the superimposed signal from the video tape and separating it into a video signal and a pulse signal; means for converting each pulse of the pulse signal read from the video tape into N-bit data according to its amplitude value; and generating a sampling signal based on the N-bit data output from the N-bit data converting means. means for sampling the N-bit data output from the N-bit data converting means using the sampling signal to generate an N-bit data signal for output.

The N data generated by the output N-bit data generation means
The present invention is characterized by comprising means for converting each N-bit data of the bit data signal into a digital value O or 1 according to its value and reproducing digital data.

(Function) In the digital data recording/playback method in the video tape recorder of the present invention, each digital value of 0.1 of the digital data is converted into N-bit data, and the N-bit data are concatenated on the time axis into N The N-bit data signal is converted into a pulse signal by converting each N-bit data of the N-bit data signal into a pulse corresponding to a respective value, and the pulse signal is further superimposed on a video signal. recorded on videotape. The video signal and the pulse signal read from the videotape are each separated,
Each pulse of the separated pulse signal is converted into N-bit data, and a sampling signal is generated from the N-bit data. The N-bit data converted from the pulse signal is sampled using this sampling signal to obtain an output N-bit data signal, and each N-bit data of the output N-bit data signal is converted into a digital value o, t, or 1. The digital data is thereby reproduced.

(Example) Next, the present invention will be explained by giving examples.

FIG. 1 is a diagram showing an embodiment of the present invention. This embodiment includes an 8-bit data generation circuit 1, a D/A converter 2, a superimposing means 3, a writing head 4, a reading head 6, a separating means 7, an A/1) Hr converter 8, and a comparator. 9, a sampling circuit 10, and a comparator 11. An 8-bit data generation circuit 1 inputs digital data indicating information to be added to a video signal and converts the digital value O of the digital data into 8 bits.
Convert the digital value 1 to bit data 80+H+ and convert the digital value 1 to 8-bit data FF+o+ to obtain the data signal 10.
Set to 1. The D/A converter 2 inputs the data signal 101 and converts the 8-bit data 80 +H in the data signal 101
+ to pulse with amplitude 0.3■, 8-bit data FF
+H+ is converted into a pulse with an S width of 0.7 V, respectively, to obtain a pulse signal 102. Generation of the above pulse signal 102 is shown in FIG. 2(a).

The superimposing means 3 inputs the pulse signal 102 and the video signal, superimposes these two signals, and sends the superimposed signal 103 to the writing head 4, which records the superimposed signal 103 on the video tape 5. The operation described above is the recording operation of digital data. Next, the reproduction operation of digital data will be explained. videotape 5
The superimposed signal 103 recorded in the recording head 6 is read out by a read head 6, and the read signal is separated into a video signal and a reproduction pulse signal 104 by a separating means 7. A/D
The converter 8 inputs the reproduced pulse signal 104 and converts each pulse in the reproduced pulse signal 104 into an 8-channel converter according to its amplitude value.
Convert to bit data.

Here, a pulse with an amplitude of 0.3■ is converted into 8-bit data of 80°, a pulse with an amplitude of Q and 7V is converted into 8-bit data FFIHI, and the reproduced pulse signal 104 becomes a reproduced data signal 105. The comparator 9 inputs the reproduced data signal 105, compares each 8-bit data of the reproduced data signal 105 with a reference value 70 no , and generates a sampling signal 106 based on the comparison result. Here, the data value of the sampling signal 106 is determined by the comparison operation of the comparator 9, and the 8-bit data is the reference value 70. The waveform of the sampling signal 106 is as shown in Figure 2 (b
) as shown below. The sampling circuit 10 inputs a reproduced data signal 105 and a sampling signal 106, samples the reproduced data signal 105 using the sampling signal 106, and generates an 8-bit data signal 107 in the form of continuous 8-bit data. The comparator 11 receives an 8-bit data signal 107, and receives the 8-bit data signal 107.
Each 8-bit data is compared with the reference value AO+o+, and reproduced digital data is generated from the comparison result. Here, the data value of the reproduced digital data is determined by the comparison operation of the comparator 11. If the 8-bit data is larger than the reference value AO+old, it is set as "1", and if the 8-bit data is smaller than the reference value AO+H+, it is set as "O". shall be. This reproduced digital data is the reproduced digital data recorded on the video tape 5 by being superimposed on the video signal. The reproduction operation of this digital data is shown in FIG. 2(b). As is clear from FIG. 2, the digital data "totoott" is correctly reproduced.

In this embodiment, the reproduction pulse signal 104 is used as the reproduction data signal 1.
8 from the sampling signal 106 generated from the reproduced data signal 105 and the reproduced data signal 105.
Since the bit data signal 107 is generated and the digital data is reproduced from the 8-bit data signal 107, the digital data can be accurately reproduced without being affected by the expansion and contraction of the video channel 15.

Furthermore, in this embodiment, by superimposing digital data indicating additional information of the video signal on the blanking period of the video signal, noise is not added to the image signal component in the video signal, so that it does not affect the image at all. It is possible to superimpose additional information on the video signal without giving any additional information.

Here, when this embodiment is applied to the signal processing section of Shinmotomat (anti-tank missile), the video signal is an image obtained by a camera installed at the tip of the missile, and the digital data superimposed on the video signal is This is information such as the direction of the missile's camera and the missile mode. The digital data superimposed on the video signal can be various information such as a video signal or a camera.

(Effects of the Invention) According to the present invention as described in detail above, digital data recorded on a videotape by being superimposed on a video signal can be accurately reproduced without being affected by expansion and contraction due to temperature changes of the videotape. be able to. Furthermore, by superimposing digital data on the blanking period of a video signal, it is possible to record and reproduce digital data without degrading the quality of one image.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the operation of recording and reproducing digital data in this embodiment,
FIG. 3 is a diagram showing the configuration of a digital data recording/playback method in a conventional video tape recorder, and FIGS. 4 and 5 are diagrams showing the operation of a digital data recording/playback method in a conventional video tape recorder. It is. DESCRIPTION OF SYMBOLS 1... 8-bit data generation circuit, 2... D/A converter, 3, 32... Superimposing means, 4, 33... Writing head, 5, 34... Video tape, 6.35.
...Reading head, 7, 36... Separation means, 8...
・A/D converter, 9.11... comparator, 1
0... Sampling circuit, 31... Pulse signal generation means, 37... Sampling signal generation means, 38...
・Regeneration means.

Claims (2)

[Claims] (1) In a video tape recorder that superimposes a video signal and digital data indicating additional information of the video signal and records it on a video tape, and plays back each of the video signal and digital data superimposed on the video tape. In a digital data recording/reproducing method, a digital value 0 of the digital data is converted to first N-bit data consisting of N bits (N is a positive integer), and a digital value 1 of the digital data is converted to the first N-bit data.
means for converting the N-bit data into second N-bit data having a different value, and generating an N-bit data signal by connecting the first and second N-bit data on a time axis; means for converting each N-bit data in the signal into a pulse having an amplitude corresponding to its value, and generating a pulse signal by arranging these pulses on a time axis; and superimposing the pulse signal and the video signal as a superimposed signal. means for recording on a videotape; means for reading the superimposed signal from the videotape and separating it into a video signal and a pulse signal; means for converting into bit data; means for generating a sampling signal based on the N-bit data output from the N-bit data converting means; and means for generating the N-bit data output from the N-bit data converting means using the sampling signal. means for sampling data to generate an N-bit data signal for output; and the N-bit data signal generated by the output N-bit data generating means.
1. A method for recording and reproducing digital data in a video tape recorder, comprising means for converting each N-bit data of a bit data signal into a digital value of 0 or 1 according to its value and reproducing the digital data. (2) The digital data recording/reproducing method in a video tape recorder according to claim 1, wherein the pulse signal is superimposed on a blanking period of the video signal.