JPS60189385A - Magnetic recorder/reproducer - Google Patents

Abstract

PURPOSE:To record and reproduce a high-band video signal and a sound signal with high tone quality simultaneously and to enable post-recording by recording a time-compressed video signal and a time-compressed sound signal by means of different double azimuth rotational magnetic heads. CONSTITUTION:Double azimuth rotational magnetic heads 5 and 6 are provided in a helical scan VTR. A video signal inputted from an input terminal 11 is synchronized and separated in a horizontal synchronizing separator circuit 12, and a clock signal is generated in a clock generator circuit 13. The A/D-converted 14 video signal is time-compressed in a time compressor circuit 15, D/A converted 16 and recorded on a tape by the heads 6a and 6b. The time compression in the circuit 15 is to input an output of a tack signal generator 25 of a cylinder rotation and that of the circuit 13. A sound signal inputted to an input terminal 19 is time-compressed in a time compressor circuit 22 and recorded on a tape by the heads 6a and 6b. Thus a high-band video signal and a sound signal with high tone quality can be simultaneously recorded and reproduced. Moreover post-recording can be possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a helical scan VTR, and particularly to a VTR suitable for recording and reproducing broadband images.

[Background of the invention]

In recent years, due to the development of broadcasting companies, plans are being made to broadcast television signals with a higher frequency band. In order to record and play back such broadcasts at home, a conventional home V'll'H
This requires a wider band of image recording capability compared to the previous model.

In order to record and play a wideband signal in a helical scan VTR, it is necessary to increase the relative speed of the head and tape, and to achieve this, it is necessary to increase the relative speed between the head and the cylinder diameter. A system in which the cylinder rotates at the field period, such as the VT C format for broadcasting, is more advantageous than the dohe9cal scan system in which the cylinder rotation period and the frame period match. However, H.R.
To achieve this with a small-diameter cylinder such as a commercial VTR, it is difficult to load the tape at a large angle, and it is difficult to keep the effect of skew on the screen within an acceptable range. be.

To solve this problem, time compress the recorded video signal.
1.5, it is sufficient to compress the video signal of one field up to the period in which the main head scans the tape in a VTR. However, in this case, the problem is how to record the audio signal accompanying the video signal with high quality.

One idea to solve this problem is to increase the time compression rate of the video signal and record the audio signal, which has been compressed in the time axis, on the video signal recording track as well, which will reduce the number of magnetic heads required. , it becomes possible to record and reproduce video signals and high quality audio signals. However, increasing the compression ratio of the video signal too much increases the increase in recording frequency, resulting in a decrease in recording density and deterioration in image quality. Also NTSC, P
In the case of a VTR that takes both AL types into consideration, it is desirable that an integer multiple of the horizontal scanning line period after time t corresponds to the rotation period of the cylinder.

Therefore, from this point of view, it is desirable that the time compression be about 5/6. Then, the tape wrapping angle around the cylinder needs to be at least 600°. In the case of a small-diameter cylinder, the tape wrapping angle around the cylinder is limited to 350°, so the wrapping angle assigned to the audio signal is 60° apart. If the video signal band is 5 MHz, the audio signal @ band is approximately 300 MHz.
It becomes KHz. This results in insufficient bandwidth to record high-fidelity PCM audio signals.

[Object of the Invention] The object of the present invention is to record and reproduce small and wideband signals.
TR9 It is an object of the present invention to provide a VTR capable of simultaneously recording and reproducing a wideband video signal and a high-quality audio signal, and also capable of dubbing a high-quality audio signal.

[Summary of the invention]

The present invention records and reproduces a video signal with time compression, and uses a separate audio signal recording head to record and reproduce an audio signal compressed at a time axis compression ratio different from that of the video signal. It is characterized by recording and reproducing.

[Embodiments of the invention]

An embodiment of the present invention will be described based on FIGS. 1 to 6. Figures 1 (a) and (b) are schematic diagrams of the cylinder section of the present invention, Figure 2 is a diagram showing its head arrangement, Figure 5 is a diagram showing its tape pattern, and Figure 4 is FIG. 5 is a schematic diagram of the recording circuit of this embodiment, and FIG. 6 is a schematic diagram of the reproducing circuit. In FIG. 1, a magnetic tape 1 (hereinafter simply referred to as tape) is connected to a tape guide 3.
4, the winding is spirally wound around the cylinder 2 with an angle θ.

The cylinder 2 is composed of a fixed lower cylinder 2b and a rotating upper cylinder 2a. Two double azimuth rotating magnetic heads 5.6 (hereinafter simply referred to as double azimuth heads) are fixed to the upper cylinder 2a, and scan the rotating magnetic heads of the upper cylinder. Arrow A in FIG. 1 indicates the running direction of the tape, and arrow B indicates the rotation direction of the upper cylinder 2a.

In this embodiment, the wrapping angle θ remains at a value of just over 300'.

The double azimuth head 5 is a head exclusively for recording and reproducing audio signals, and the double azimuth head 6 is a head exclusively for recording and reproducing video signals. To double azimuth.

The head 5 is composed of a head portion 5a having a +azimuth and a head portion 5b having a +azimuth. To the double azimuth, the drawer is similarly composed of + azimuth head y to f9J + 6aJ-- azimuth head to do i6b. In this embodiment, the head track widths of the respective dots are made equal. As shown in Fig. 2, dos 5 and 6 are in the rotational axis direction (height direction).
and are arranged at a predetermined distance in the circumferential direction. FIG. 2 shows an enlarged view of this part. The head parts 5a and 5b are arranged at approximately the same height, and the head parts 6a and 6b are also arranged at approximately the same height. The difference in height between the heads 5 and 6 needs to be a constant value in order to obtain a tape pattern to be described later. However, the circumferential spacing between heads 5 and 6 can be freely selected. In the figure, these heads are arranged close to each other, but it is also possible to arrange these heads far apart, for example, at 180°11[6t] in the circumferential direction.

FIG. 3 shows a track pattern recorded on the tape. FIG. 3 shows only the tracks recorded by two rotations of the upper cylinder 2a. That is, in the first rotation of the cylinder, the do 5a records the track 7a, and the draw a records the track 8a. Head 5b with one continuous rotation
The head 6b records the track 7b, and the head 6b records the track 8b.

The tracks 7a and 7b record time-compressed audio signals, and the tracks 8a and 8b record time-compressed video signals.

Each of these tracks is recorded without a guardband portion, so-called azimuth overlap. A timing chart of these recordings is shown in FIG. Portion 9 of Hara Hasen statue signal 9
a, 9b, 9c are each compressed in time axis to become 9'a
, 9'b, and 9'c are the recorded video signals output at the timings 9'b and 9'c. Just these periods are head 6
The rotation of the cylinder is controlled so that it is within the period in which the tape is being scanned. Portions 9'a, 9'b, 9'c are recorded alternately by heads 6a, 6b. The same goes for the audio signal, and the parts 10a and 10b of the original audio signal 10
, Inc is time axis compressed to 10'ag10'b, 10
This is the recorded audio signal output at timing 'c. 1
The output timings of 0'a, 10'b, and 10'c are selected so that the head 5 is scanning the portions shown in 7a and 7b in FIG.
recorded in a and 5b'. heads 5a, 5b
, or to, doro a.

6b is slightly apart in the circumferential direction, so 8a and 8
b. When tracks 7a and 7b are output at the same timing relative to cylinder rotation, recorded track 8a,
and 8b, and 7a and 7b are slightly shifted in position in the scanning direction.

If there is a margin in the winding angle of the tape, it is also possible to record with the tape out of alignment. If it is necessary to eliminate this discrepancy or to adopt a so-called H arrangement in the video signal, the output timing of the compressed signal should be set at each 9'a.
, 9'b.

It is sufficient to slightly shift every other one in 9'c or 10'a, 10'b, and 10'c.

In this example, the time compression ratio of the audio signal is in the range (
In the limit, up to 5//s is possible.

However, if compression is not done too much, the band will not increase much, but the lengths of tigers, 7a, and 7b will become longer, and the relative 1c
Since 8a and 8b are shortened, there is a j& point on the system.

Next, I will explain the recording circuit based on the professional diagram in Figure 5.
f52 clear. The video signal inputted from the λ power terminal 11 is synchronously separated by a horizontal synchronous zero separation circuit 12, and a black and ray generator t@13 generates chromatic and ray signals synchronized with the horizontal synchronization. Kugata video signal is N wheat.

The signal is sampled by the converter 14 using the sampling link pulse from the black and white generation circuit 15 and converted into a digital signal.

The output of the wheat converter 14 is time-compressed in the digital signal domain by a time compression circuit 15.

This time compression is carried out at the timing shown in FIG. 4 using the output of the tack signal generator 25 for cylinder rotation and the time compression pulses of the black/red generation circuit 13 as input. The output of the time compression circuit 15 becomes an analog signal time-compressed by the D/A converter 16, and the output from the frequency modulation circuit 17.
The data is recorded on the tape by the heads 6a and 6b via the recording amplifier 18.

The audio signal input to the input terminal 19 is chimbled by the sampling pulse outputted from the black and white generation circuit 13 and converted into a digital signal by the rice converter 20. After an error correction bit is added to this signal in an error correction bit adding circuit 21, the signal is sent to a time compression circuit 22 using the output of the signal generator 25 and the time compression signal ν from the clock pulse generation circuit 13. time compression as shown in FIG. The output of the time compression circuit 22 is transmitted to the modulation circuit 23. Through the recording amplifier 24, to, 5a, 5
b is recorded on tape.

Next, the regeneration circuit shown in FIG. 6 will be described.

During playback, the playback output from the heads 6a and 6b is .

After being amplified by the doors 26 and 27 and alternately switched between SUI and P2B, it is modulated by the demodulation circuit 29. The demodulated signal is a time-compressed video signal. A synchronizing signal is separated from this signal by a horizontal synchronization separation circuit 30, and a black and red signal synchronized with the reproduced horizontal synchronization is produced by a black and white generation circuit 31 which receives this signal as input. The video signal compressed for L time by this clock is chimbled by the Het-t converter 32 and made into a digital signal, and then time-expanded by the time expansion circuit 33 to make it into a digital video signal of the original time length. The signal is returned to an analog signal by the λ converter 34 and supplied to the video signal output terminal 50.

The reproduced audio signals from the amplifiers 55 and 5b are amplified by the amplifiers 55 and 56, which are alternately switched by the switch 37, and the time-compressed digital audio signals are demodulated by the demodulation circuit 38. The output of the demodulation circuit 38 is expanded to the original time length by a time expansion circuit 40, error corrected by an error correction circuit 41, and then converted back to an analog signal by a D/A converter 42 to output an audio signal. terminal 6
0.

In the embodiments described above, the time compression and expansion of the video signal was performed in the digital signal domain.

However, of course, this may be done using an analog memory such as a CCD and using the analog signal as it is without converting it to a digital signal. Furthermore, although the horizontal synchronization signal is used as the time axis reference, a dedicated pilot signal may also be recorded. In addition, a head amplifier was provided for each head in the reproducing circuit, but since there is no period in which signals are being reproduced simultaneously by DR A and 6B, and 5A and 5B, the DR amplifier was made common, and one for each head was used, totaling 2. It is also possible to make it a game. At this time, there is no need for rapid signal switching, so if necessary, the reproducing head can be switched using a switch. It is also possible to perform this switching within the upper cylinder), thereby making it possible to reduce the number of channels of the rotor 9 transformer. Of course, if you can get enough hair 1, you can connect the playback heads in series and get the playback signals of 5a, 5b, or 6a, 6b from the same channel, halving the number of channels of the rotary transformer. Depends.

Furthermore, when used as a camera-integrated VTR, time compression of the video signal as shown in Figure 914 can be performed by controlling the video camera signal and start-up using cylinder rotation synchronization pulses. It is obvious that it depends.

Furthermore, in the embodiments so far, only audio signals have been considered as signals to be recorded by the double azimuth head 5, but it is not possible to add digital non-data accompanying television signals, such as character signals of teletext broadcasting, to this. It is clear that this can be done easily based on the explanations given above.

In the examples so far, we have not specifically described the tape running control method, but this may be a method using conventional control signals, or a method that uses a frequency multiplexing method to superimpose the pilot signal for the tiger and king onto the audio signal or video signal. It is also possible to record the oath and use it to control tape running during playback. Alternatively, a method may be adopted in which a tracking pilot recording area is provided on the extension line of the track 7 or 8 in FIG. 3, and the tape running is controlled by the pilot signal reproduced from this area.

〔Effect of the invention〕

According to the present invention, since a time-compressed video signal and a one-hour compressed audio signal are recorded and played back using separate double azimuth heads, the time compression ratio of the audio signal can be widened without increasing the time compression of the video signal. It is possible to select from a wide range, and it is possible to record and reproduce high-quality or multi-channel audio signals. Also, since audio and video are recorded and played back using separate heads, you can use heads that are suitable for each.
A rational design becomes possible, and a VTR capable of recording and reproducing wideband video signals and wideband audio signals can be obtained.

In the father's method, the sound is recorded and played back using a separate head, so dubbing is extremely easy, so-called overlapping 4F erasing is possible, and fixed erasing is also possible.

It is also possible to perform erasing using an erasing head having gears and pads in the width direction corresponding to the tracks 7a and 7b.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an outline of the cylinder section of an embodiment of the present invention, FIG. 2 is a diagram showing the head arrangement, FIG. 3 is a diagram showing the tape pattern recorded on the tape, and FIG. 5 is a block diagram of the recording circuit, and FIG. 6 is a block diagram of the reproducing circuit. 1... Magnetic tape, 2... Cylinder, 5, 6...
Double azimuth circuit magnetic head, 7.8... Track, 15.22... Time compression circuit, 35.40... Time expansion circuit. No.) E (O-) (b) 2nd Ward No. 31!1 A Nozomi

Claims (1)

[Claims] A magnetic recording and reproducing device characterized in that a helical scan VTR is equipped with a plurality of double azimuth rotating magnetic heads and records time-compressed video signals and time-compressed audio signals using different double azimuth rotating magnetic heads. Device.