JPH01100708A - Rotary head type recorder - Google Patents

Abstract

PURPOSE:To miniaturize a device and to make it light weight by specifying a tape attaching angle on a cylinder provided with first and second rotary heads. CONSTITUTION:The first rotary head which performs the helical recording of an audio signal on a first area extending in the longitudinal direction of a tape while the video signal of prescribed periods is rotated at theta deg., and the second rotary head rotated on a rotational plane different from that of the first rotary head and which performs the helical recording of the audio signal of prescribed periods on a second area set in parallel with the first area while it rotates at psi deg. are provided. And the tape attaching angle on the cylinder provided with the first and second rotary heads are set at an angle <= (theta+psi) deg.. Therefore, since it is possible to increase the angle theta according to the above, the diameter of the cylinder can be decreased. In such a way, it is possible to miniaturize the device and to make it light weight.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a rotary head type recording device, and particularly to a rotary head type recording device that helically records video signals and audio signals in separate areas on a tape. be.

<Prior Art> Hereinafter, a home video tape recorder (VTR) will be described as an example of this type of device in this specification.

Generally, a so-called rotating two-head helical scan type VTR is known for home use.

FIG. 6 is a diagram showing the arrangement of heads of this type of VTR. In FIG. 6, 1 is a magnetic tape, and 2a and 2b are tape guides for winding the tape 1 around the outer periphery of the rotating drum 3 over an angular range of IJ 30° or more.

HA and HB are rotating heads that are respectively attached to the rotating drum 3 with a phase difference of 180 degrees, and have different azimuth angles.

As is well known, the heads HA and HB record and reproduce one field of video signals while rotating 180 degrees.

In this type of VTR, the track length of the video signal for one field is predetermined in the standard, so the diameter of the rotating drum 3 is necessarily determined accordingly. Therefore, the diameter of this drum cannot be made smaller, which hinders the reduction in size and weight of VTRs.

Therefore, the following VTRs have been proposed and implemented as VTRs whose drum diameter can be reduced. 7th
The figure shows the head arrangement in a conventional VTR having a small diameter drum. In the figure, Ha and Hb are rotary heads having different azimuth angles, and rotate once during one field period of the video signal. Tape 1 is 3θ with respect to drum 4
The rotary heads Ha and Hb record video signals for one field while rotating by 3θ°. That is, the video signal for one field is recorded in a period shorter than the original period of one field of the video signal.

Therefore, the video signal recorded by this basic VTR is N.
When assuming a TSC signal, it is not a normal NTSC signal, that is, a signal with a vertical scanning frequency (fv) of 5 Q Hz and a horizontal scanning frequency (fr() of 15.75 KHz) (fv is 6 Q Hz).
0Hz, fr(ga(15,75×9A ”-) 18.
9 Must be from KH2.

In other words, the video signal recorded by this type of VTR must be a normal television signal that has been time-axis compressed to 100% in units of one field, or a signal obtained from a dedicated camera.

The dedicated video camera described above scans a screen with an aspect ratio of 9:10 (indicated by the dotted line Y in Figure 8), and its inner cylinder 8
The screen with an aspect ratio of 3:4 shown by the solid line X in the figure is output as an effective screen within the % field period, and the head H
a, Recorded in Hb.

The timing at the time of recording will be explained using the timing chart of FIG. 9. In the period indicated by T in the figure,
A video camera (not shown) scans a Y screen with an aspect ratio of 9:10, and as shown in FIG. 9(a), a continuous 315
A video signal consisting of a horizontal scan of the book is obtained.

However, since the heads Ha and Hb actually trace on the tape 1 only a percentage of that within each field period, 262.5 horizontal scans are taken out as shown in FIG. 9(b). , recorded on magnetic tape as a video signal with an aspect ratio of 3:4. At this time, the head Ha.

Since Hb is alternately traced on the magnetic tape, the VTR with the head arrangement shown in FIG. 7 can perform recording similar to the VTR with the head arrangement shown in FIG. 6. However, since it is necessary to provide a slight phase difference between the heads Ha and Hb at this time, it is necessary to appropriately delay the video signal of the first field or the second field.

If video signals are recorded as described above with the head arrangement as shown in FIG. 7, the drum diameter can be reduced to the VTRX shown in FIG.

<Problems to be Solved by the Invention> Incidentally, in recent VTRs, in order to improve the sound quality of recorded and reproduced audio signals, a track for digital audio signals is provided on an extension of the track on which the video signal for one field is recorded. There is a recording format in which a large number of video tracks are formed in one area extending in the longitudinal direction of the tape, and a large number of audio tracks are formed in the other area.

FIG. 10 shows a recording format on a tape by this type of VTR, where V is a video area, Vt is a video track in which one field's worth of video signal is recorded, and A
is an audio area, and At is an audio track in which audio signals for one field period are digitally recorded.

The digital audio signals recorded on each audio track At are time-axis compressed to a fraction of the time. For example, if the digital audio signal recorded on this audio track At is time-axis compressed by %, the length of the track At will be % of the length of the track Vt. When the recording format shown in Fig. 10 is realized with the head arrangement shown in Fig. 6, if the time axis compression rate of the audio signal is expressed as %, then the tape can be placed on the drum 3 over an angular range of 210° or more. It needs to be wrapped.

On the other hand, when realizing the recording format as shown in FIG. 10 with the head arrangement as shown in FIG.
It is necessary to wrap the wire over an angular range of 5θ° or more. However, it is virtually impossible to wind the tape around the drum 4 over an angular range of 350' or more, considering the presence of the tape guides 5a and 5b.

Furthermore, if the time axis compression rate of the audio signal is low, it is physically impossible to record it. In general, in a VTR that aims to downsize the drum by recording one field of the video signal while rotating through an angle of 180 degrees or more, a recording format as shown in Figure 10 is realized. was difficult.

In view of such problems, the present invention provides an apparatus for helically recording a video signal in a first area extending in the longitudinal direction on a tape and an audio signal in a parallel second area using a rotating head. The aim is to reduce the turning radius of the machine and make the device more compact.

<Means for Solving the Problems> For this purpose, in the rotary head type recording device of the present invention, the video signal for a predetermined period is rotated by θ0 while extending in the longitudinal direction of the tape. a first rotary head that performs helical recording in a first area; the first rotary head rotates on a different rotational plane, and records audio signals for the predetermined period in the first area while rotating by ψ°; a second rotary head for performing helical recording in a second area parallel to the first area; The tape application angle to the cylinder provided with the second rotary head was set to be less than (θ+ψ)0.

<Operation> By rotating the first rotating head for video signals and the second rotating head for audio signals on different rotating surfaces, the first rotating head and the second rotating head move to different positions in the width direction of the tape. The two rotary heads trace at the same time, and the recording timings of the first area and the second area can partially overlap. Therefore, the attachment angle of the tape to the cylinder was set to be less than (θ+ψ)0. Along with this, θ can be made large, so the diameter of the cylinder can be made small.

<Examples> Examples of the present invention will be described below with reference to FIGS. 1 to 5. FIG. 1 shows a VTR as an embodiment of the present invention.
Figure 2 is a diagram showing the positional relationship between the head and tape of the VTR in Figure 1, Figure 3 is a diagram showing the schematic configuration of the VTR in Figure 1.
FIG.

In the figure, H1 and H2 are video rotary heads, H3 and H4 are audio rotary heads, and these are attached to a rotary head cylinder 11. As shown in FIG. 2, the magnetic tape T is wound around the cylinder 11 nine times over an angular range of 3θ° or more by means of tape guide posts 12a and 12b. Also, the rotating surfaces of heads H1 and H2 are head H3,
It is shifted by a distance with respect to the rotation plane of H4. The heads H1 and H2 have different azimuth angles, and the head H1 and H2 have different azimuth angles.
3 has the same azimuth angle as head H1, head H4 has the same azimuth angle as head H2, heads H1 and H2, heads H3 and H4
rotate with rotational phases as close to each other as possible.

In FIG. 1, 21 is a terminal to which an analog audio signal is input, and the input analog audio signal is digitized by an analog-digital (A/D) converter 22 and then supplied to a digital signal processing circuit 23. Ru.

The digital signal processing circuit 23 performs well-known processing such as adding redundant codes such as error correction codes, data shattering, and time axis compression.
The signal is supplied to the head changeover switch 8W3 via the side terminal. The head changeover switch SW3 is alternately connected to the heads H3 and H4 every rotation of the cylinder 11.

As mentioned above, 24 scans a screen with an aspect ratio of 9:10 with 315 horizontal scanning lines, and the effective screen is 262.
This is an overscan camera that outputs five images.

On the other hand, a video signal in a signal format conforming to a standard television signal is inputted to the terminal 25 from an external device such as a television tuner, and this video signal is sent to the time axis compression circuit 25.
By compressing the time axis to % in units of one field, the output signals of the overscan camera 24 are made to have the same signal format. The output signal of the overscan camera 24 and the output signal of the 1-time axis compression circuit 26 are selected by the switch SW5 and supplied to the recording signal processing circuit 26.

The recording signal processing circuit 27 operates at an operating frequency 1.2 times that of a conventional VTR, and produces a signal form suitable for magnetic recording.

The output of the circuit 27 is input to the head changeover switch SW4 via the R side terminal of the recording/reproduction changeover switch SW2.

Switch 8W4 also alternately switches the head H every one field period.
1 side and head H2 side.

FIG. 4 is a diagram for explaining the trace positions of each head in the VTR of FIG. 1, and FIG. 5 is a timing chart showing the operation timing of the VTR of FIG. 1.

Rotating surfaces of rotating heads H1 and H2 and rotating heads H3 and H4
Due to the distance between the heads H1 and H
The recording locus tv of No. 2 and the recording locus ta of the heads H3 and H4 are arranged as shown in FIG. 4, and the recording of the video signal and the recording of the audio signal occur at the same time.

Referring to FIG. 5, assume that the distance is set so that heads H3 and H4 form one track in the audio area in the last % of the period in which heads H1 and H2 form one track. The operation timing will be explained below.

FIG. 5(a) shows the envelope waveform of the video signal output from switch SW5, and FIG. 5(b) shows the envelope waveform of the video signal output from switch SW5.
This signal indicates, at a high level, the timing at which recording is being performed.

Further, (C) is a signal indicating at a high level the recording timing of the heads H3 and H4 determined by setting the distance as described above. When recording a digital audio signal at the timing shown in FIG. are shown in (d) and (e).

In FIGS. 5(d) and (e), 81.82 is the timing at which the analog audio signal is sampled by the A/D converter 22 processed in the system and taken into the RAM, Pl, P2 are R, 1. Timing for adding redundant data to audio data imported into AM and performing data sharding. R2 indicates the timing at which data is read from the RAM.

By the way, the above-mentioned distance is set so that the recording timing of heads H1 and H2 and the recording timing of heads H3 and H4 are in the desired relationship, but when recording is performed in a tape format as shown in FIG. If this is desired, the tracks in audio area A and video area V must be aligned in a straight line, and the azimuth angles must be made to match. Therefore, if the track pitch is 'rp, the head H
1. If the rotational phases of H2 and heads H3 and H4 are the same, D must be an even multiple of Tp. Also head H
If the rotational phase of heads H3 and H2 is x0 ahead of the rotational phase of heads H3 and H4, it is necessary to set D=(++-)Tp. However, the tape T is conveyed in the direction shown in FIG. 4y. That is, heads H1 and H that are transporting the tape
The distance is determined so that the trace locus of No. 2 and the trace loci of heads H3 and H4 are shifted by an even multiple of the track pitch.

During reproduction, the signals reproduced by the heads H1 and H2 are returned to their original signal form by the reproduction signal processing circuit 31 via the P side terminal of the switch SW1, and converted into % in units of one field by the time axis expansion circuit 32. The time axis is expanded and the signal is outputted from the terminal 33 in the same signal format as a standard television signal.

Further, the digital signals reproduced by the heads H3 and H4 are sent to the digital processing circuit 34 via the P side terminal of the switch SW1.
After processing such as time axis expansion and error correction, the signal is converted into an analog signal by a digital-to-analog (D/A) converter 35 and outputted from a terminal 36.

According to the above-mentioned VTR, the cylinder diameter can be made small, and one field's worth of video signals and digital audio signals can be recorded on the same straight line.

In the above embodiment, the video signal heads were a pair of heads arranged close to each other on the cylinder and having different azimuth angles, but for example, four heads having different ψ° rotational phases may be sequentially used to form a cylinder. A VT that records video signals on a tape wrapped over an angular range of 270° or more.
It is also possible to apply the present invention to R. In this case, similarly, four audio rotary heads having mutually different ψ° rotational phases can be realized by rotating on a rotation plane different from that of the four video rotation heads.

<Effects of the Invention> As explained above, according to the present invention, video signals and audio signals are helically recorded in the first and second regions extending in parallel in the longitudinal direction on the tape, respectively. The rotating head type recording device can be made smaller and lighter.

[Brief explanation of the drawing]

1 is a diagram showing a schematic configuration of a VTR as an embodiment of the present invention, FIG. 2 is a diagram showing the positional relationship between the head and tape of the VTR of FIG. 1, and FIG. 3 is a diagram of the VTR of FIG. 1. 4 is a diagram showing the trace position of each head in the VTR shown in FIG. 1, FIG. 5 is a timing chart showing the operation timing of the VTR shown in FIG. 1, and FIG. 6 is a diagram showing the head configuration. Figure 7 shows the head arrangement of a conventional VTR with a conventional small-diameter drum. Figure 8 shows the scanning of a video camera dedicated to a VTR with the head arrangement shown in Figure 7. FIG. 9 is a timing chart showing the operation timing of a VTR with the head arrangement shown in FIG. 7, and FIG. 10 is a diagram showing a conventional recording format on tape according to the present invention. Hl and H2 are rotating heads for video, H3 and H4 are rotating heads for audio, 11 is a rotating head cylinder, 12a
, 12b is a tape guide post, 22 is an analog-to-digital converter, 23 is a digital signal processing circuit, 27 is a recording signal processing circuit, and T is a magnetic tape. Figure 3 Figure 4 Figure 5 Figure 6 Figure 9

Claims (1)

[Claims] a first rotary head that helically records a video signal for a predetermined period in a first area extending in the longitudinal direction of the tape while rotating it by θ°; and a first rotary head that rotates on a different rotational plane from the first rotary head. and a second rotary head that helically records the audio signal for the predetermined period in a second area parallel to the first area while rotating by ψ°; The angle of attachment of the tape to the cylinder is (θ+ψ
) A rotary head type recording device characterized by being less than )°.