JPH0267089A - Recording and reproducing device - Google Patents

Abstract

PURPOSE:To perform recording of two channels with a small cylinder without increasing the number of heads by winding a tape across the cylinder on which four heads are loaded at a winding angle >=180 deg. and supplying the signals of the two channels to the four heads at a time expansion circuit and a switching circuit. CONSTITUTION:The tape 12 is fed by winding across a rotary cylinder 17 having the four heads arranged with an interval of 90 deg. with an angle >=270 deg. spirally. Meanwhile, the signals of the two channels are supplied from input terminals 20-21, and are switched sequentially by a recording switching circuit 22 corresponding to the 1/2 rotation of the cylinder, and after they are time-expanded at the time expansion circuits 23-26, they are supplied to recording amplifiers 27-30, and are amplified by degree required for recording. Furthermore, the output of the recording amplifiers 27-30 are supplied from recording and reproducing change-over switches 31-34 to the heads 13-16 via a 4CH rotary transformer 35, and are recorded sequentially on the tape. In such a way, it is possible to perform multichannel recording without increasing the number of heads.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a recording/reproducing device.

Conventional technology As an effective means of downsizing conventional home-use two-head helical scan VTRs, the cylinder diameter was reduced to two while maintaining compatibility.
A small-diameter cylinder system with a 270 degree winding that can be made 3 times as large has been put into practical use.

(Japanese Patent Publication No. 45-20403) In this method, as shown in Fig. 2, heads 1 to 4 are
The tape 6 is arranged at equal intervals around the cylinder 5 with a diameter of 3, and the tape 6 is wound over 270 degrees along the cylinder 5 and run in the direction of the arrow 7, and the cylinder is rotated at 3/2 times the normal rotation speed. This is realized by giving the following in the direction of arrow 8.

Reference numeral 9 is a signal switching circuit which sequentially selects one of the three henodes in contact with the tape at the same time as the tape rotates, and supplies a signal through the 4CH rotary transformer 1) to convert the normal 2
Its role is to provide head scanning equivalent to that of the head cylinder.

Problems to be Solved by the Invention Is this method advantageous for downsizing?
Because they are arranged every other time, twice the number of heads is required.

In addition, if applied to the miniaturization of the two-channel component recording system VTR used for broadcasting, eight heads would be required, and many heads would be mounted on a small cylinder, making it impractical. When applied to the helical scan method, there were problems in terms of size and cost.

Means for Solving the Problems In order to solve the above problems, the present invention wraps a tape around a cylinder mounted with four heads at a winding angle of 180 degrees or more, and switches the two-channel signal with a time expansion circuit. 4 in the circuit
By applying this to each head, two-channel recording can be performed using a small cylinder without increasing the number of heads.

Also, since the head switching times of the two-channel signals differ between channels by 174 of the rotation period of the cylinder, a delay of 1/4 of the rotation period of one channel is applied when recording, and the rotation period of the other channel is delayed. 1/4 of
Perform a time delay during playback. Furthermore, by dividing the video signal into horizontal periods, expanding the time by two times, and recording the signal divided into two channels, wideband recording can be performed.

Furthermore, if the time expansion circuit is given an expansion rate that is smaller than the increase rate of the wrapping angle from 180 degrees, it is possible to add a third intermittent signal to the expanded signal and record it, and to add recording of PCM audio, etc. I can do it.

According to the present invention, unlike a normal 180-degree winding cylinder, a plurality of heads are in contact with the tape, and by supplying different signals to each of the heads using a switching circuit, it is possible to record a plurality of consecutive signals. Because I can,
For example, a 270 degree winding 2 channel recording and reproducing apparatus can be constructed using the same 4-channel groove as the 270 degree winding 1 channel cylinder.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows the configuration of the recording/reproducing apparatus of the present invention.

In FIG. 1, the tape 12 is spirally rotated by N=90°, that is, 2
Wrap it around 70 degrees or more and run in the direction of arrow 19.

On the other hand, the two-channel signals are applied from input terminals 20 to 21, are sequentially switched by a recording switching circuit 22 according to 1/2 rotation of the cylinder, are time expanded by time expansion circuits 23 to 26, and then sent to recording amplifiers 27 to 30. The outputs of the recording amplifiers 27-30 are supplied to the heads 13-16 through the recording/reproduction changeover switches 31-34 and the 4CH rotary transformer 35, and are sequentially recorded on the tape.

On the other hand, during playback, the output signal from the throat is passed through a rotary transformer 35 and given to playback amplifiers 36 - 39 from recording/playback changeover switches 31 - 34 and amplified, and then time compressed by time compression circuits 40 - 43 and sent to a playback changeover circuit 44 . After being sequentially switched in accordance with the rotation of the cylinder, the signals are output from the output terminals 45 to 46.

If the two-channel signal is the luminance/color signal of the video signal, color video can be recorded.

It can also be used to simultaneously record audio channels and information channels other than video.

In this case, it is better to use a line-sequential color signal in which the R-Y and B-Y components are alternately transmitted in one channel.
A time complex color signal obtained by compressing and connecting -Y and B-Y components may also be used. Alternatively, the same processing may be applied to the I2Q components, or a color signal created by quadrature two-phase modulation with R-Y and B-Y components may be used by adding a carrier. Further, the luminance signal may also be subjected to FM modulation.

Next, the operation during recording will be explained with reference to FIG. 3rd CH
The input signal shown in FIG.
It is switched between A and CHIC every 1/2 rotation (rotation angle π) of the cylinder. Further, the CHIA and CHIC signals are expanded by about 1.5 times in time in the time expansion circuits 23 to 26 as shown in FIGS. 3A and 3C, but it is sufficient if the time is at least 1 times or more. The 4th part also shows the results of CI (B and D signals processed in the same way as in 1 and created by CH2, and the A and B signals are switched and expanded every 1/2 rotation.
There are four types of intermittent signals: , C, and D. Figure 5 is 4
This figure shows the situation when four heads contact the tape 4 as the cylinder 47 rotates. That is, move the four heads in the direction of cylinder rotation A49. B50. C51, D52
Assuming that the moment when head A starts to touch the tape due to cylinder rotation is cylinder rotation angle O (radian),
This is the moment when head B finishes scanning the tape. Furthermore, head C has just started scanning and has advanced by π in cylinder rotation angle, and head D has just started scanning and has advanced by π in cylinder rotation angle.
You can see that it has advanced by /2.

In this way, the state of tape scanning with respect to the cylinder rotation angle of each head changes one after another, and the state is shown in a table as shown in FIG. 6. 4 shown in Figure 5, in the case of 1270 degree winding, each head scans the tape for 3/4 rotation period of the cylinder and idles for 1/4 rotation period as shown in Figure 6. I understand. Therefore, these A,
This shows that if the signals A, B, C, and D in FIG. 4 are supplied to the B, C, and D heads, it is possible to record two different channels of signals independently.

Further, during reproduction, it is sufficient to switch to the time axis expansion circuits 40 to 43 in FIG. 1 and reproduce the originally continuous signals using the circuit 44 in the reverse process of FIG. 4.

The trunk formed on the tape at this time is shown in FIG. As can be seen from the figure, the head ABC and D trajectories are arranged in parallel at equal intervals, and two channels of signals can be recorded. In the figure, 53 to 56 are Henodo A~
This is a track by D. The interval between the trunks is the length of the tape fed in the track inclination direction during the time the cylinder rotates by π/2, and when the tape feed is 33.3 mm/sec and the cylinder rotation speed is 1800/min, the interval is 29 μm, which is about 25 μm wide. It is convenient to use a zero head because it has a suitable guard. Furthermore, by giving different azimuths to A, C, and BD, it is possible to perform efficient recording without guard bands using a wide hennode having a width of 35 to 45 μm.

Furthermore, when the present invention is used to record video signals, there will be channels where the signal switching position is in the middle of one field, so for example, a 1/2 field delay circuit may be used to push the switching position into the vertical synchronization signal. It is also possible to deviate from interference. In FIG. 8, reference numeral 57 indicates a 1/2 field delay circuit, which corresponds to the recording/reproducing device 5859 in FIG. 9th
In the figure, CHI CH2 is a 2-channel video signal, 60 is a vertical synchronization part, and CH2D is a signal delayed by 1/2 field.
By connecting to the input shown in FIG. 1, the switching point can be removed from the screen. Furthermore, the video signal can be divided into horizontal blanking months as shown in FIG. 10, and can be used to record a signal that is time-expanded twice to have two channels. In Figure 10, 61 is horizontal blanking, the numbers 1 to 7 are horizontal line numbers, IN is the input signal, and CH1 and CH2 are divided into horizontal blanking periods and time-stretched twice. This shows a signal with two channels.

Figure 1) shows a circuit that divides each horizontal blanking period and expands the time twice to create two channels.The signal input from the input terminal 62 is switched to a switching switch 63 synchronized with the horizontal period.
The data is switched and inputted alternately to the memory 64 and 65. On the other hand, a clock is passed to the memory from the clock generation circuit 66 and the divide-by-2 circuit 67, and the time is expanded by two times.
Obtain the signals of CH1 and CH2 in the figure.

Further, in these examples, the video signal is simply used, but in the case of a VTR, the video signal is often FM modulated and recorded. However, regardless of the modulation, the same effect can be obtained by applying the two-channel recording method of the present invention. In this case, there is no restriction on the location where the modulators are installed, and if it is acceptable for the number of modulators to increase, they may be inserted after the time expansion circuits 23 to 26 in FIG. The demodulator can also be used anywhere after the playback head amplifier.

No. 12121 shows an embodiment in which the expansion rate is set to (180+N)/180 or less and an intermittent signal such as a PCM audio signal is added to the remaining portion for recording. If N = 90 degrees, the wrapping angle is 270 degrees, and the expansion rate is 4/3, the signal in Figure 12A will have a length of 240ft (4/3π) after expansion, as shown in Figure 12(b). The same figure (
Adding the intermittent signal of length 30 degrees (π/6) shown in a), the same figure (C), (length 270 degrees (3/2π) as shown in dl)
Create. FIG. 13 summarizes the results similarly generated in the second channel. In the same figure, S is the third signal of intermittent shape, CHl, CH2, A, B, C,
D corresponds to CHI CH2, A, B, C, and D in FIG.

The third Shingetsu can perform intermittent recording four times per cylinder rotation and is suitable for recording PCM audio signals. The track pattern in this case is shown in FIG. Figure 68
7 shows that compared to the trunk pattern of FIG. 7, the rear part of the tape is allocated to the third signal, and the PCMC-audio and video tracks 70 are divided and recorded on one track. In this example, the third signal is assigned to the back of the trunk, but it would be the same if it was assigned to the front.

Effects of the Invention As described above, the present invention is effective in YC separated component recording VTRs, wideband recording VTRs, etc. because multi-channel recording can be performed without increasing the number of beds and channels.

For example, when applied to a 1/2-inch, 2-channel component type VTR used for broadcasting, the number of heads remains 4, but the cylinder size is 2/3 of the standard size.
can be configured while maintaining compatibility.

Furthermore, by making the cylinder shape the same as that of the conventional one-channel system, it is possible to construct a two-channel VTR that is compatible with a color under-one-channel VTR represented by the VH 3-way system. Furthermore, according to the present invention, when recording, the time expansion circuit performs time expansion, which narrows the frequency band of the signal, making it possible to lower the carrier frequency when recording with FM modulation. Effects such as improved characteristics can be expected without the use of .

Furthermore, by inserting a delay circuit of 1/2 cylinder rotation time into one channel during recording and into the other channel during playback, seamless recording within the screen is possible.

Furthermore, if the time expansion ratio is set smaller than the ratio of increase in the wrapping angle from 180 degrees, a VTR with PCM audio can be constructed in which an intermittent third channel such as PCM audio can be recorded in the remaining portion and post-recording can be performed.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a recording/reproducing apparatus of the present invention, FIG. 2 is a configuration diagram of a conventional recording/reproducing apparatus, FIG. 3 is an explanatory diagram of signals in an embodiment of the present invention, and FIG. 6 is an explanatory diagram showing the period during which the cylinder in FIG. 5 is in contact with the tape; FIG. 7 is a tape pattern diagram of the recording/reproducing apparatus of the present invention; FIG. Figures 9 to 9 show a delay circuit with a cycle of 1/2 rotation of the cylinder inserted into one channel during recording and the other during playback to eliminate noise from the playback screen by aligning the head switching position between channels. Explanatory diagrams of the embodiments, Figures 10 to 1)
The figure is an explanatory diagram of an example in which a signal of 2 channels is recorded by time-expanding a 1-channel signal by 2 times.
2 to 14 show that in the present invention, the time expansion ratio is selected to be smaller than the increase ratio of the wrapping angle from 180 degrees, and the third
FIG. 2 is an explanatory diagram of an embodiment in which intermittent signals are also recorded. 12...Tape, 13 14 15.16...
...Henod, 17...Cylinder, 22.
44...Switching circuit, 23-26...
- Time axis expansion circuit, 40 to 43... Time axis compression circuit. Name of agent: Patent attorney Shigetaka Awano (1 person) Figure 7m 7c 7c Adjustable angle diagram Figure 10ゝG7 Figure 1 2 Figure 13

Claims (5)

[Claims] (1) Hold the tape at least 180 degrees + N degrees (0<N<18
0) Wrap it in a spiral and run it, dividing the 2-channel signal every 1/2 rotation of the rotating body (180+N)/18
A recording/reproducing apparatus comprising a time expansion circuit that performs time expansion of 0 times or less, and simultaneously recording continuous signals of two channels by supplying the output of the time expansion circuit to the four heads. (2) The recording/reproducing apparatus according to claim (1), wherein one of the signals of the two channels is delayed by a time of 1/4 of the rotation period of the rotary body when the other is recorded and the other is reproduced. (3) Claim (1) or (3) wherein one of the two channel signals is a luminance signal component of the video signal and the other is a color signal component.
The recording/reproducing device according to any one of 2). (4) Claim (1) in which a 2-channel signal obtained by dividing a 1-channel video signal by a horizontal blanking section and expanding it twice is used as the 2-channel signal.
Or the recording/reproducing device according to any one of (2). (5) The recording and reproducing apparatus according to claim 1, wherein the time expansion ratio is set to be smaller than (180+N)/180, and a third intermittent signal is added for recording and reproducing.