KR910000187B1 - Going and coming recording regeneration storage - Google Patents

Abstract

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Description

Reciprocating Record Playback Method

1A and 1B are a side view and a plan view showing an outline of a cylinder portion of a rotating two-head helical scan type magnetic recording and reproducing apparatus.

2A and 2B are recording pattern diagrams for explaining the concept of the round trip recording / reproducing method of the present invention.

3 is a circuit block diagram showing the configuration of one embodiment of a round trip recording / reproducing method of the present invention.

4A and 4B are recording pattern diagrams showing an example of a pilot signal recording method according to the present invention.

Fig. 5 is a recording pattern diagram showing an example when applied to the 8 milli video deck of the present invention.

* Explanation of symbols for main parts of the drawings

1: A / D converter 2: Controller

3, 4: memory 5: modulator

6 adder 7 pilot signal generator

8 gate circuit 9 recording amplifier

10, 19: switch 11: regenerative amplifier

12: HPF 13: demodulator

14: D / A converter 15: LPF

16: frequency converter 17, 18: BPF

20, 21: level detector 22: differential amplifier

23: sample holder circuit

The present invention relates to a recording and reproducing method of recording and reproducing a sequentially compressed information signal with a recording trajectory inclined with respect to the longitudinal direction of a tape-shaped recording medium.

In the conventional helical scan type magnetic recording / playback apparatus, the tape traveling direction is generally one direction.

By the way, in the audio tape recorder using the fixed head, the recording can be performed for a long time by the auto reverse without reversing the cassette.

The reason why the automatic reverse video recording apparatus does not exist in the helical scan video tape recorder is that the helical scan video tape recorder has the following problems.

In a home VTR or the like, it is configured to record one feed image signal on one recording track. To divide the area in the tape width direction and use the area appropriately according to the running direction of the tape, According to this method, it is possible to consider the method of switching the tape running position up and down on the circumference of the rotating head cylinder, and (b) using a different rotating head for each driving direction. It is practically impossible to switch the tape running height on the cylinder circumference up and down because it is necessary to wind the tape around the rotating cylinder and run it while maintaining the precision of several microns. In addition, the method of (b) requires two sets of rotating heads, which makes the apparatus extremely complicated and is not a suitable method. In addition, in the conventional home VTR, the control track and the audio track are required, so when the reciprocating recording is attempted, two control tracks and two audio tracks (four in stereo) are required. Grows For the above reason, in the apparatus for recording and reproducing video signals, recording has been realized for a long time by recording in only one direction by improving the recording density rather than extending the recording time by a round trip recording method.

However, when reproducing a tape recorded for a long time, the rewinding time is inevitably long, resulting in a long waiting time.

In the helical scan video tape recorder, the reciprocating recording is difficult due to the above reasons. However, a method of performing reciprocating recording relatively easily by time-compressing an audio signal with a rotating head and recording PCM can be considered.

SUMMARY OF THE INVENTION In the recording and reproducing apparatus for recording and reproducing a time-compressed information signal with a recording trajectory inclined in the longitudinal direction of a tape-shaped recording medium, the reciprocating recording of the tape-shaped recording medium is relatively easy to be performed. .

)에 걸쳐서 상기 테이프형상 기록매체의 길이방향에 대하여 경사진방향으로 주사하는 기록재생용 헤드를 가지고, 상기 기록매체의 주행방향에 따라서, 상기 기록재생용 헤드가 주사궤적의 상기 기록매체의 폭방향에서 분할된 각각의 영역에 각각 시간압축된 정보신호를 기록하도록 구성한 것이다.The present invention provides a substantially full width in the width direction of a tape-shaped recording medium.

Has a recording / playing head for scanning in a direction inclined with respect to the longitudinal direction of the tape-shaped recording medium, and according to the traveling direction of the recording medium, the recording / reproducing head is a width direction of the recording medium in the scanning trajectory. The time-compressed information signal is recorded in each of the divided areas.

Hereinafter, the tape reciprocating recording method of audio signal time compression PCM recording by helical scan type rotating head recording according to the present invention will be described in detail according to the accompanying drawings.

1 is a diagram for explaining a tape traveling system of a helical scan type rotary head recording apparatus. In Fig. 1, the magnetic tape T is inclinedly wound around the rotation cylinder D on which the magnetic heads A and B are mounted.

2 is a diagram for explaining a recording pattern in the present invention. In FIG. 2A, if the trajectory C scanned by the head A (or B) when the tape T is stopped is referred to as C, the tape T moves forward in the forward direction Vta. The scan trajectory is (a), and the scan trajectory when the tape T proceeds in the backward direction (Vtb) is as shown in (b). It is assumed here that the heads A and B proceed at a speed of V _{H in the} direction of the arrow. As shown in FIG. 2B, the present invention allows a time-compressed PCM audio signal to be recorded on the lower half of the tape when the tape travels in the forward direction at a speed of Vta, for example. When traveling in the backward direction at the speed of (Vtb), the time-compressed PCM audio signal is recorded on the upper half of the tape.

In this way, the tape is wound around the rotary cylinder so that the rotating head generally comes in close contact with the full width of the tape, and time-compressed audio signals are recorded in the lower half and the upper half of the tape at the time of advancing and reversing the tape, respectively. You can write back and forth on the tape. In this case, the scanning angles of the recording tracks are different at the time of advancing and reversing, but at the time of reproducing, the recording is reproduced by head scanning corresponding to the angle of each recording trajectory, so that tracking can be performed without any problem.

In the example of FIG. 2B, since both sides of the tape are unstable in contact with the rotating head and the tape, the track T ₁ (T ₂ ), which enables the fixed head recording, is left, and the guide W for vertical separation is provided in the center. Forming.

Next, the signal processing and control system will be described with reference to FIG. In FIG. 3, the audio signal of (L) (R) input from the input terminal is input to the A / D converter 1, and the (L) (R) is sampled from each other and converted into a PCM signal. The output of the A / D converter 1 is input to the controller 2 and again to the memory 3. In this memory 3, information is stored, for example, between the cylinders (FIG. 1d) rotating halfway. In the next half-turn, the PCM information is stored in the memory 4 and the PCM information stored in the memory 3 is read at a speed faster than the writing speed (for example, n times). In the next half-turn, the PCM information is written into the memory 3, and the information stored in the memory 4 is read out at a faster speed (n times) than at the time of writing.

The signal read out from the memory is subjected to error correction encoding in the controller circuit 2 and input to the modulator 5. The modulator 5 is converted into a modulation signal suitable for recording, input to the adder 6, combined with the signal of the pilot signal generator 7 for tracking, and input to the gate circuit 8. The read timing from the memory and the gate timing of the gate circuit 8 are controlled by the pulse generator 30 described later. The output of the gate circuit 8 is written on the magnetic tape by the heads A and B via the switch 10 via the recording amplifier 9.

During reproduction, the signal reproduced from the heads A and B is amplified by the reproduction amplifier 11, the PCM signal is separated by the HPF 12, and the tracking pilot signal is separated by the LPF 15. . The PCM signal separated by the HPF 12 is demodulated by the demodulator 13 and then input to the controller 2 again. The memory 3 is alternately written to the memory 3 and the memory 4, the information of the memory 3 is read out in the period of being written in the memory 4, and the memory 4 is written in the period of being written in the memory 3; ) Information is read. At the time of reproduction, the read rate from the memory is slowed down (for example, 1 / n) for read-write maturity to the memory as opposed to the time of recording, error correction is performed, and input to the D / A converter 14 for reproduction. Audio signals L and R are obtained.

However, as the pilot signal for tracking, the same 4-frequency pilot method as that employed by the 8 millisecond video tracking method can be adopted. 4 frequency pilot method is as follows.

The four frequencies f ₁ , f ₂ , f ₃ , and f ₄ in sequential cyclic switching are recorded per tracking. Where (f _A ) and (f _B ) are specific signals of different frequencies. In the case of 8 millisecond video, f _A = f _H , f _B = 3f _H , f _H are set to be the horizontal scanning frequency of the television signal.

This tracking pilot signal is separated from the above-described LPE 15 and input to the frequency converter 16 to be frequency-converted by the reference oscillation signal of the pilot signal generator 7 and adjacent by the BPFs 17 and 18. The component of the crosstalk component (f _A ) (f _B ) from tracking is derived. The components of this (f _A ) (f _B ) are input to the level detectors 20 and 21 via the switches 19 (SW ₂ and SW ₃ ). The outputs of the detectors 20 and 21 are input to the differential amplifier 22, draw out the level difference components, and are input to the sample holder circuit 23. In the sample holder circuit 23, for example, in FIG. 2B, when the tape is traveling in the (Vta) direction, the period of (P ₁ ) to (P ₂ ) leads the differential amplifier output to the output as it is. The period of (P ₂ ) to (P ₃ ) operates to sample and level the level of (P ₂ ). On the contrary, when the tape is traveling in the (Vtb) direction, the period of (Q ₂ ) to (Q ₃ ) leads the output level of the differential amplifier as it is, and the period corresponding to the period of (Q ₁ ) to (Q ₂ ) It operates to sample and level (Q ₃ ). The capstan motor is controlled by the signal of the output terminal 24 of the sample holder circuit 23 to maintain correct tracking.

On the other hand, with respect to the control of the cylinder motor, the phase obtained by comparing the signal of the clock generator 25 divided by 1 / m in the frequency divider circuit 26 with the PG head output for detecting the cylinder rotation position is compared with the phase comparator 27. The cylinder motor is controlled by the error signal. The A / D converter 1, the controller 2, the modulator 5, the D / A converter 14 and the like operate in synchronization with the clock of the clock generator 25.

In addition, the PG head output for detecting the cylinder rotational phase is input to the pulse generator 30 by adjusting the phase by the monostable multi-29. Pulses of respective timings synchronized with the PG head output are generated by the pulse generator 30 to switch the pilot frequency of the tracking pilot signal generator 7, and to control the timing of the memory control of the controller 2 and the gate circuit 8. Gate, control of the switch 19, timing of the sample holder circuit 23, and the like are controlled. In addition, a control signal (H or L) for switching various pulse generation timings of the pulse generator 30 is input from the terminal 31 in accordance with the advance direction and the reverse direction of the tape.

The function of the switch 19 is to make the operation of matching the polarity since the order of the four-frequency pilot is set so that the polarity of the control signal is reversed for each track.

In addition, in the above description, the tracking pilot signal has been described on the premise that the pilot signal from adjacent tracking is reproduced with crosstalk. However, in order to do this, the gap between the two heads (A) and (B) in FIG. By changing the angle (azimuth), a method of eliminating gaps between tracks and recording is effective. By recording and reproducing with such a head with different azimuth angles, the high frequency PCM signal adds a large azimuth loss to reduce the crosstalk, and since the low frequency pilot signal has little azimuth loss, adjacent track crosstalk components can be satisfactorily reproduced. .

2 and 3 illustrate the method of recording the pilot signal for tracking over all tracks, but as shown in FIG. 4A, the pilot signal P is recorded only at the start and end of each track. However, as shown in Fig. 4B, a method of recording the pilot at three positions of the start, middle, and end of each track may be considered.

In the case of FIG. 4A, it is preferable that the pilot signal of each track start stage is bias-recorded using the preamble signal of the signal as an alternating bias, and the pilot signal of the end stage is bias-recorded using the postamble as an alternating bias. In the case of FIG. 4B, the pilot signals of the track start and end stages are bias-recorded as described in FIG. 4A, and the pilot part PM in the track is not an information signal but transmits only a middle amble (synchronous clock), which is an AC bias. Can be used as

By partially recording the pilot signal in this manner, the adverse effect of the pilot signal on the PCM signal can be eliminated, and for tracking, it is possible to maintain a stable tracking state by using a sample holder circuit such as (23) in FIG. will be.

However, recording of a PCM voice signal such as the present invention can be easily realized in 8 milli video decks. 5 shows a recording pattern when the recording of the present invention is performed in 8 milliseconds videotec. In Fig. 5, the region I is an 8-millimeter video original PCM audio region, but the region II is an 8-millisecond video signal recording region. For example, the region I is divided into two tapes up and down. When recording proceeds in the (Vta) direction and in the (Vtb) direction, the recording is performed. In addition, if the output of the third frequency division circuit 26 is 60 Hz, and the pilot signal frequency is the same as that of 8 millisecond video, the control system can be shared almost entirely.

In addition, the present invention does not require any tracking control circuit system by a pilot signal in FIG. 3 when applied to an apparatus that has a control track and a tracking control by a fixed head like a VHS VTR. The signal 26 obtained by dividing the signal of 25) may be set to 60 Hz (50 Hz in the case of the PAL system VTR), and this signal may be used as the vertical synchronization signal of the television signal.

In addition, the output of the frequency divider circuit 26 does not necessarily need to be selected as 60 Hz or 50 Hz, and it is possible to configure the control circuit according to the output of (26).

In the above description, the rotating two-head helical scan method has been described as an example. However, the two-head helical scan method may also be applied to the two-head helical scan. It goes without saying that not only the helical scan but also the vertical scan can be applied.

In addition, in FIG. 2 and FIG. 4, the recording area of the PCM signal is divided into two up and down, but the time compression ratio is made larger (in this case, since the bit rate is large, the relative speed of the head tape must be corresponding to that). It is also possible to divide the area and the lower area into two or more areas to increase the number of recording channels during round trip.

The present invention can be applied not only to recording a voice signal but also to a signal similar to the voice signal or a signal such as digital data.

The present invention can also be applied to recording and reproducing not only a magnetic recording and reproducing apparatus but also other tape-shaped recording media.

According to the present invention, in a device in which a sound head is recorded with a time-compressed PCM signal, the tape can be reciprocated and recorded, and the tape needs to be rewound when the tape comes to an end in one direction. It is possible to record and play continuously.

Claims (5)

A recording / reproducing head (A, B) capable of scanning in a direction inclined with respect to the longitudinal direction of the tape-shaped recording medium generally over the full width in the width direction of the tape-shaped recording medium (T), The time-compressed information signal is recorded in each area of the scan trajectories (a, b) of the head divided in the width direction of the tape-shaped recording medium in the forward driving direction and the backward driving direction of the recording medium. And reproducing the information signals recorded in the respective areas according to the travel directions (Vta, Vtb) of the shape recording medium, and obtaining a signal in which the time axis is extended to its original state. The reciprocating recording and reproducing method according to claim 1, wherein a magnetic tape is used as the tape-shaped recording medium (T), and only one rotating magnetic head is used as the recording and reproducing heads (A, B). The reciprocating recording and reproducing method according to claim 1, wherein magnetic tape is used as a tape-shaped recording medium, and two rotating magnetic heads having different azimuth angles are used as recording and reproducing heads. The reciprocating recording / reproducing according to claim 1, wherein the recording area in the forward direction Vta running and the recording area in the backward direction Vtb running of the tape-shaped recording medium are further divided to increase the number of channels of the recording signal. Way. The reciprocating recording and reproducing method according to claim 1, wherein the pilot signal (P) for tracking is partially recorded at least at the start end and the end end of the scan trace.

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