JPS59221854A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To record and reproduce plural kinds of information on one oblique track by operating a pilot tracking circuit only for a time corresponding to a divided reproducing track. CONSTITUTION:Oblique tracks 10-16 are formed on a magnetic tape 1, and plural kinds of information are recorded and reproduced divisionally on each oblique track and pilot signals are recorded divided oblique tracks respectively. In case of reproducing of the tape 1, a video signal and a PCM signal of a channel A are reproduced simultaneously or only PCM signals of channels B-G are reproduced, or only the PCM signal of the channel A is reproduced. In this case, gates 58, 59 and 61 and a sample holding circuit 69 are made conductive and tracking is controlled by a capstan motor 45. For example, in case of reproducing of only the channel A, the pilot signal is reproduced only in the trace time of heads 23a and 23b to perform tracking.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a two-head helical scan type information recording and reproducing device, and more particularly to a magnetic recording and reproducing device suitable for recording and reproducing a time-compressed audio signal. .

[Background of the invention]

Conventional examples of 2-helical scan type information recording and reproducing devices include a home video tape recorder represented by the VH8 system, whose tape pattern is shown in Figure 1, and a home video tape recorder called the 8-helical video standard, whose tape pattern is shown in Figure 2. There is a video tape recorder.

In FIG. 1, 1 is a video tape, 2 is a video track on which video signals are recorded, 5 is a control track on which control signals are recorded, and 4 is an audio track on which audio signals are recorded.

Reference numeral 5 indicates the direction in which the rotary head traces, and arrow 56 indicates the direction in which the video tape runs.

θ1 in FIG. θ2. θ3 indicates the angle at which the video tape is wound around the rotating cylinder,
θ1L:tθ3#5°, θ2=1so'. θ2 corresponds to the recording period of the video signal, and θ1° to θ5 are margins for ensuring compatibility.

In FIG. 2, 7 converts the audio signal into a PCM signal,
Further, a track on which a signal whose time has been compressed to about one-sixth is recorded, 8 is a first option track, and 9 is a second option track.

In FIG. 2, θ1. θ2. θ3. θ4 indicates the winding angle of the video tape wound around the rotating cylinder, respectively, θ1ζθ5#5°, θ2#180°, θ4=5
It is 0°. θ4 corresponds to the period during which the audio signal is recorded, and θ1. θ2. θ3 is the same as in FIG.

In this way, in the past, it was only possible to record one or two types of information on a single diagonal track, narrowing the scope of use of video tape.

there was.

[Purpose of the invention]

The purpose of the present invention is to eliminate the drawbacks of the conventional technology, and to make it possible to record and reproduce multiple types of information on one diagonal trunk.
An object of the present invention is to provide a magnetic recording and reproducing device that expands the range of use of cassette tapes.

[Summary of the invention]

In the present invention, as shown in FIG. 5, one diagonal track is divided into N pieces, and N pieces of information (A to Q in FIG. 5) are independently recorded and reproduced on each i track. independently recorded,
In addition to multiplexing the pilot signal with information so that it can be played back.

During recording, the signal created by dividing the frequency of the crystal oscillator output and the rotation speed of the rotating head are synchronized in phase.

[Embodiments of the invention]

FIG. 6 shows an example of the case where the present invention is applied to a video tape recorder of 8mm video standard.

FIG. That is, one diagonal track is 10
It is divided into 7 information tracks of 16 to 16, and 7 information tracks A to G are provided. In the tape turn shown in Figure 6, 220μ of tape is wrapped around the rotating cylinder.

A, G) Rack is 65° curly, B, C, D
, E.

The F track wraps around 50 degrees.

FIG. 4 shows the magnetic field of the present invention for recording both the tape pattern of FIG. 2 and the tape pattern of FIG. 5.

1 is an example of a block diagram showing main parts of a recording/reproducing apparatus. FIG. 5 is a waveform diagram of each part of FIG. 4.

Ru.

The operation in FIG. 4 will be explained below using FIGS. 6, 4, and 5.

First, the case of recording the tape pattern shown in FIG. 2 will be described. This means that the audio signal is sent to trunk A in Figure 5.
The time-compressed signal converted to a CM signal is recorded, and B, C,
D, B, F, G) - Corresponds to recording video signals on the rack.

In FIG. 4, 17 is a video signal input terminal;
18 is a video signal recording processing circuit.

At 18, the chroma signal in the video signal is frequency-converted to a low frequency band, and the luminance signal is converted to an FM signal. .

19 is an arrow indicating the running direction of the tape. 20 is.

It is a write amplifier, and the output signal is sent to the rotating head 25a.
, 2+b is recorded on tape 1.

22a and 22b are input terminals for two-channel audio signals, and 21 is an audio signal recording processing circuit.

At 21, the audio signal is converted to a PCM signal, and then about 7
time is compressed.

28 is a pilot signal generator which outputs signals of four different frequencies. That is, the output σ of the pulse generator 27
) becomes High or Low, f1 → f2 → f
Pilot signals are output in the order of 3→f4→f1→f2... 27 output signal High, Low
w is associated with the rotating heads 25a, 25b;

In Fig. 4, when 23a is recording rack B,, -F), the output signal σ) of 27 is High, and 25b is recording B~F).
When recording the F track, the output signal σ) of 27 is L.
It becomes OW. The output signal of the pilot signal generator 28 is σ
) are associated with high and low signals,
(I) When the signal is High, fl or f5. σ) signal is L
暉.

When , it becomes f2 or f4.

An example of a pilot signal is f1#6.5fh.

f2 #75 fh, f3-t 10.5 fh
, f4L:r95 fh , (fh.

:Horizontal synchronization frequency).

Therefore, the circuit 1 is connected to the rotating heads 25a and 25b.
A signal obtained by mixing six output signals, ie, the output signal No. 8, the output signal No. 21, and the output signal No. 28, is applied.

Next, phase synchronization of the cylinder motor 26 will be explained using FIG. 5. When recording a video signal, in order to prevent switching noise from appearing on both sides, the recording position of the vertical synchronization signal must be set at a predetermined position at the bottom edge of the tape (in Figure 3, b).
and c + h, the boundary between in and O).

For this reason, the vertical synchronization signal is the same as the video signal.

The period separation circuit 52 extracts the waveform shown in Fig. 5 σ) 24
a and 24b are two magnets attached to the rotating cylinder, and from the pink up head 25°, H
I get a pulse like . In Figure 4.5, the magnet is attached slightly ahead of the head of 25a) 24
A positive pulse is output from the magnet 24b, and a negative pulse is output from the magnet 24b, which is attached to a position slightly ahead of the head of the magnet 25b.

The output signal 0 of the pick amplifier head 25 becomes a waveform (Io) by passing through a pulse processing circuit 27 consisting of a delay circuit, a waveform shaping circuit, and the like. In FIG. 5, (Io) is not shown, but has the same frequency as the (I) signal shown in the first drawing, but a different phase.

The monomulti 56 is a vertical synchronization signal frame.
, change to R. In this case, the switch 61 is connected to N, and phase error signals (E) and (■0) are obtained at the output of the phase comparator 60, which is amplified by the motor driver 29 and drives the cylinder motor 26. Therefore σ)
The timing of the signal and (, J) signal is as shown in Figure 5.
Phase synchronization is achieved with the rise of the α) signal slightly ahead of that of the g) signal.

Next, the control of the capstan motor 45 will be described. In order to set the tape feed speed to a predetermined value, a so-called quartz chronograph system is used.

ing. That is, take the capstan motor 45.

The output signal of the rotation speed signal generator consisting of the attached FG 46 and the pick-up node 47 is sent to the frequency divider 42 by the frequency divider 40.
, 41, the signals are frequency-divided into corner x nagi, and a phase comparator 43 compares the phases of the signals. A phase error signal which is an output signal of 45 is amplified by a motor driver 44 and drives a capstan motor.

Next, a case will be described in which a time-compressed audio signal is recorded only on the A track.

In FIG. 4, the switch 51 is connected to the A side.

Q in FIG. 5 indicates the time axis. That is, time is a
−+ l) −+ , C−+ d −+ 6−+ f
→g, the head 25a traces the rack A-F in FIG. When you reach the middle of g, go to the throat 2
5b starts tracing the A track.

In FIG. 5, at time g T h +1, both the throats 25a and 23b trace the tape. Similarly a * b + C and In , n
*O also has both heads tracing the tape.

The pyro-node signal generator 28 in FIG. 4 is preferably simple so that two heads can write the pyro-node signal on the tape at the same time using the same pilot signal.

-\During the period when the throat 25a is tracing the A track,
The head 25b will trace the racks F and G). When forming the tape turn shown in Figure 2,
When the throat 25a traces the B-G rack, the pyro throat frequency is set to fl or f5, and the head 25
b is B-G) When tracing the rack, the pilot frequency is set to fl or f4.

Therefore, the pilot frequency during the period when the head 25a traces the A track is fl or 5f4.

In addition, in this case, it is difficult to decide on fl, and fl
or f4.

FIG. 6 is a tape pattern diagram when recording is made only on the A track. In the figure, A1, A3, A5, A
7 is formed by the head 25a, and A2. A4. A11 is formed by the head 25b.

The pilot signal recorded in A1 is fl or f4.

In FIGS. 5 and 6, the case where fl is reached is explained. In this case, A2. A3. A4. A5.

A6. The pilot signal of A is f5 * f4 r f
l , fl r f5f4.

Next, a method of generating timing pulses necessary for the above signal processing will be explained. In the tape pattern shown in FIG. 6, the winding track is divided into six equal parts B to G, with a track corresponding to an angle of 180 degrees. The signal corresponding to this 180° wrapping angle is σ) in FIG.
) may be used as a timing pulse.

For example, when the present invention is used in an NTSC 8m standard video tape recorder, the cylinder motor needs to rotate at about 50 Hz. If the frequency of the crystal oscillator 59 is 3.58 MI (z (color subcarrier frequency)), then N1X N2 1o) The signals are phase-synchronized, and as shown in FIG. 5, (M) and σ) become signals whose phase 1 frequency also coincides. Therefore, if N of the branching unit 64 is set to 12, a timing pulse of @) can be obtained.

The frequency divider 65 divides the signal (G) into 6 different phases (
If, 50', 60u, 90', +20', 1
50' ) signal (Ll, B2 +...L, s)
Output. These L1 to L6 are selected by the data selector 36, and when recording on the A track, Ll is output, and when recording on the B) rack, B2 is output.

The output signal Li of the data selector 66 controls the audio signal processing circuit 21 to generate a PCM signal at the timing described above.

Next, the branch unit 40. , 5B branching ratio N1. N2 will be explained. Since N5 = 12, NI XN2 9
It becomes 954. The simplest phase synchronization system for the capstan motor 45 is N42N5=1. In this case, if N2-1 is used, the output frequency of the divider 41 will be approximately 560 Hz, which is a value that is easy to create as an FG46. Therefore, it becomes N1#9954.

Next, a case will be described in which another audio signal is recorded on the B track of a tape on which a signal has already been recorded on the A track. The tape pattern in this case is shown in FIG.

When recording a signal on the B track, when a control signal is applied to the channel select terminal 57, the data selector 56
The signal B2 in FIG. 5 appears at the output. Therefore, the signal for the period ~b becomes B1, the signal for the period ch becomes 82, and! The signal for the period .about.n becomes B5, forming a tape pattern as shown in FIG.

The pilot signal written to B1 is %f1 for the reason mentioned above.
Alternatively, it becomes fs, and FIG. 5 shows the case where it becomes f5.

Therefore, B1 has fl as B2, B5 + B4
+B5 +B6B7 has f4 * fll f2
t fs p f4 t fl are written respectively.

In FIG. 7, the track trajectories of A1 and B1 are shifted by about half the track pinch.

Track A and track B are recorded separately, so A1
It is not possible to control the relative positions of %A1 and B, and there are cases as shown in FIG. 7, and cases where %A1 and B1 are on the same straight line.

However, when playing a tape like the one shown in Figure 7, it is rarely necessary to play tracks A and B at the same time.
The deviation between A1 and B1 is not a problem.

That is, when reproducing only the A track, it is sufficient to reproduce the pilot signal only during the period when the heads 25a and 2b trace the A track to obtain tracking. In this way, tracking will not be disturbed by signals written on tracks other than the A track.

After all, in order to play the tape pattern shown in Figure 7, what should A) be done during track A? A necessary condition is that a tracking control signal (ie, a pilot signal) dedicated to tracking is recorded.

In FIG. 4, the pulse processing circuit 27 outputs 2 of IIo.
Outputs two pulses. ■ and 10 are signals with the same frequency but different phases, and the timing relationship between ■ and J is the fifth
The circuit 27 is adjusted as shown in the figure.

The delay circuit 35 is provided to align the phases of Ll and 1 in FIG. 5, and in the servo locked state, the phase relationship between I and M is the same as the relationship between ■ and J, so %M is This results in a slightly delayed pulse.

The switch 48 is a switch for switching the control signal to the circuit 21, and when recording video and audio simultaneously, the switch is connected to the N side and a - signal is applied to the circuit 21.

The circuit 21 outputs signals q1 and A1 . A2...
Apply the signal to write amplifier 2o.

The amplifier 20 receives a video signal (V in FIG. 5) from the circuit 18.
)5 The pilot signal P from the circuit 28 and the signal ■ from the switch 48 are applied to the video heads 25a and 25b.
N1. A recording signal current of O, is applied.

The signal waveforms when recording an audio signal only on the B track are R2, G2, N2, R2, and the switch 4F3 is connected to the A side. The signal waveform when recording an audio signal only on the C track is R3, G3. N3.03 and A
The signal waveform when recording audio signals only on the track is L.
l, G, +N7107.

The switch 48 is connected to the N side when recording a video signal, and to the A side when recording only an audio signal.

The reason why the switch 48 is necessary is to eliminate the influence of the phase error between the signal 2 and Ll, and if this phase error can be suppressed sufficiently, the switch 48 is not required. In this case, the switch 48 may remain connected to the A side.

FIG. 8 shows a block diagram of an embodiment of the write amplifier 20 used in the present invention. In FIG. 8, 49 is a video signal and pilot signal mixing circuit, 50 is a PCM signal and pilot signal mixing circuit, 51° and 52 are for signal switching, and 55
, 54 is a switch circuit for squelch, when the control terminal is Low, it is V, N side (black circle side), when it is High Q, it is A, 8
Connected to the side (white circle side). 55 and 56 are drive amplifiers, and J7 is a two-channel rotary transformer.

The switch 58 is connected to the N side when recording video and audio simultaneously, and to the A side when recording only audio, and cuts off signals outside the period to be recorded when recording only audio.

59, 60, and 61.62 are AND circuits.

FIG. 9 is a block diagram showing one embodiment of the reproducing circuit of the present invention, and FIG. 10 is a waveform diagram showing signal contents of each part in FIG. In FIG. 9, 49 is Ni.

A preamplifier that takes O1' as an input signal and outputs Ri and Si; 50 is a video signal reproduction processing circuit; 51 is a video signal output terminal; 52 is a PCM audio signal reproduction processing circuit; ', Li' are input signals, and two-channel audio signals are output. 55 and 54 are output terminals for audio signals.

55 is a linear amplifier, and for reasons explained later, R
Since the level of the pilot signal included in 81 is lower than that of the pilot signal included in i, this is to amplify them to the same level. 56 is a switch, 57 is a BPF for pilot signal extraction, 58 and 59 are gate circuits, and 60 is a converter, which outputs the product of the output signals of 58 and 59. 61 is a gate circuit.

62 is a HighQ BPF with a center frequency fh;
5 is the BPF of the river ghQ with a center frequency of 5fh, 64.6
5 is an amplitude detector, 66 is a differential amplifier, 67 is an inverter, 68 is a switch, 2B, 60, 62,
65, 64°65, 66, 67, 4 by 6B
It constitutes a frequency pilot type tracking error detection circuit.

69 is a sample and hold circuit, and 70 is a delay circuit, which has a delay time slightly larger than that of 65 in FIG.

71 is an inverter, 72 is a switch, 76 is a frequency dividing circuit of □954, 74 is a frequency dividing circuit of i and 8, and Li'
and Gf' are output. 75 is a data selector, and 76 is a switch.

In Figure 9, (1) video signal and P of channel A
There are three ways to use it: (2) playing back only the B-G channel PCM signals; and (6) playing only the A-channel PCM signals.

The operation of the switches 48, 72, 76.degree. 56 in this case is shown in FIG.

In the state (1), the reproduction signal from the head is the 10th
N1' + 01' in the figure, and the video signal R1 and PCM signal S1 appear at the output of the preamplifier 49. The pilot signal in R1 is extracted by BPF57.

Tracking is controlled by a capstan motor 45. At this time, the output Gi' of the data selector 75 becomes High for the entire period, and the gates 58, 59, 61 and sample old 69 become conductive. Game) 58.59゜61
, one sample hold 69 is sufficient, but the gate circuit and the sample hold 69 may be used together.

In state (2), for example during B channel playback, the playback signals from the head are N2', o2',
Due to the switch operation shown in FIG. 14, the output signal of the preamplifier becomes S2. In the figure, N/A indicates N.

This means that either is fine. In order to detect the tracking error from the pilot signal during S2,
The G2' signal is output to the data selector 75 to gate the tracking error signal.

In state (5), unlike state (2), the video head 25a reproduces the pilot signals of f2', f, and the video head 25b reproduces the pilot signals of f, , f5. Tracking cannot be achieved with the same configuration as (2) (see Japanese Patent Laid-Open No. 116120/1983).

). Therefore, the switch 76 corrects the above.

FIG. 11 is a block diagram showing another embodiment of the reproducing circuit of the present invention. The difference from FIG. 9 is that a switch 77 is provided in place of switch 76, and the operation of each switch is shown in FIG.

FIG. 12 is a block diagram showing another embodiment of the reproducing circuit of the present invention. The difference from FIG. 11 is that an inverter 79 and a switch 7 are provided instead of the switch 720. The operation of each switch is shown in FIG.

FIG. 13 is a block diagram showing another embodiment of the reproducing circuit of the present invention. The difference from FIG. 19 is that a switch 7 and an inverter 79 are provided in place of switch 76, and the operation of each switch is shown in FIG.

FIG. 18 is a block diagram showing an example of the preamplifier 49 used in the present invention. 80 is a preamplifier IC.

81.82! 86 is an input terminal for a reproduction signal, 86 is an output terminal for outputting a video signal under normal conditions, 84 is an output terminal for outputting an A channel PCM signal under normal conditions, 85 is an input terminal for head switch pulses (I', Li), 86 87 is a rad-up, 88 and 89 are switches, 90 is an inverter, and 91 and 92 are buffer amplifiers. Normally, the amplifier gain of the 91 is set to be about 10 dB larger than that of the 90. The reason is that the PCM signal leaking into the video signal is difficult to tolerate because it causes visible interference, but there is no problem with the video signal leaking into the PCM signal as long as it is below the threshold of 5. Sometimes it is desired to extract the chroma signal or pilot signal multiplexed with the video signal at the highest possible level.

For this reason, an amplifier 55 is provided in Nos. 9.11 and 12.15 to amplify the pilot signal from the output terminal 84.

FIG. 19 is a circuit diagram showing an embodiment of the sample and hold circuit 69 used in the present invention.

In FIG. 19, 92 is an input terminal, 96 is a terminal to which a gate pulse Gi' is applied, and 94 is an output terminal.

During the period when the terminal 96 is High, the signal at the input terminal 92 is directly transmitted to the output terminal 94, and when the terminal 93 becomes Low, a pre-hold is performed by the function of the capacitor 95, and the tracking error voltage is held. 9.11
, 12. Gate circuits 58 , 59 , 6 in Figure 15
1 transmits the input signal during the HIGH period of the Gi' signal, and cuts off the input signal during the LOW period. There are many possible places to insert the gate circuit, but considering the DC offset, B P
The input side of F62 and 65 is desirable.

FIG. 20 is a block diagram showing one embodiment of the audio signal recording processing circuit 21 used in the present invention. In the figure, 97a
r, 97b are analog compression circuits, 98a, 98
b is an A/D converter, and 99 is a digital signal processing circuit consisting of a time compression circuit, an error correction signal addition circuit, and the like.

100 is a phase comparator circuit, 101 is a VCo, and 102 is a frequency dividing circuit, which constitutes a PLL. 105 is a digital pulse delay circuit that utilizes the output signal from the frequency dividing circuit, and converts the 2 or Li signal in FIG. 5 into a Gi-fold signal. The PLL circuit generates 2fH and 5B6fH from the frame frequency (I or Li).

21H is the sample pulse for the AD converter, and the 586 fH signal is the PCM signal (
195f which is A 11 "0" of Ai, Bi...)
n, A111 is used to generate a 16 fH pulse.

FIG. 21 is a block diagram showing one embodiment of the audio signal reproduction processing circuit 52 used in the present invention. In the figure, 104 is a digital belief processing circuit consisting of a time expansion circuit, an error correction circuit, etc., 105a and 105b are DA=+ inverters, and 106a and 106b are analog expansion circuits, which have almost inverse characteristics to the compression circuits 97a and 97b. have

〔Effect of the invention〕

According to the present invention, by simply adding a few circuits to a conventional video recorder, it is possible to record both video signals and high-fidelity audio signals. In particular, the audio signal recording capacity is comparable to that of an audio compact cassette, and ultra-high-fidelity stereo signals can be recorded for more than 10 hours.In terms of sound quality, the compact cassette metal has a recording time that is more than 1D times that of conventional compact cassettes. It is possible to obtain better characteristics than normal eyes.

It is possible to combine the same characteristics as such a high efficiency, super high-fidelity recording device and the conventional recording device into a single device.

Of course, it goes without saying that the present invention is also of great value as a recording-only device for recording and reproducing multiple types of audio information.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a tape pattern of a conventional home video tape recorder, FIG. 2 is a diagram showing a tape button of the 8I+I+1+ video standard, and FIG. 5 is a tape button diagram for explaining the present invention in detail. FIG. 4 is a block diagram showing an embodiment of the recording circuit of the present invention, FIG. 5 is a diagram showing signal waveforms of each part in FIG. 4, and FIGS. 6 and 7 are tape patterns recorded by the apparatus of the present invention. FIG. 8 is a block diagram showing an embodiment of the write amplifier used in the present invention. FIG. 9 is a block diagram showing an embodiment of the reproducing circuit of the present invention.
The figure shows the signal waveforms of each part in Figure 9, 11th and 12th.
, 13 is a block diagram showing another embodiment of the reproducing circuit of the present invention.
1.12.15 is a diagram showing the switch operation, FIG. 18 is a block diagram showing one embodiment of the preamplifier used in the present invention, and FIG. 19 is a circuit diagram showing one embodiment of the sample hold circuit used in the present invention. , FIG. 20 is a block diagram 21 showing an embodiment of the audio signal recording processing circuit 21 used in the present invention.
The figure is a block diagram showing one embodiment of the audio signal reproduction processing circuit 52. As shown in FIG. Explanation of symbols 1...Magnetic tape, 25a, 25b...Rotary head, 10, 11, 12, 15, 14, 15
, 16... Divided diagonal trunk, 28... Pilot signal generator, 58, 59° 61... Gate circuit, 69... Sample hold circuit (pre-hold circuit). 14 figures, 14 figures, 1S figure,

Claims (1)

[Claims] An information recording/reproducing apparatus using a two-helical force scan method, comprising: means for forming a diagonal track on a magnetic tape; and means for dividing the diagonal track into a plurality of pieces for recording and reproducing;
means for recording a pilot signal in each of the divided diagonal tracks, and when reproducing only an arbitrary track among the divided tracks, a pilot tracking circuit is provided for a period corresponding to the reproduced track. A magnetic recording/reproducing device characterized in that it is provided with at least a gate circuit or a pre-hold circuit for operation.