KR900008445B1 - Cue signal recording method - Google Patents

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Description

Cue signal recording method

Fig. 1 is a diagram showing a recording track on a tape when a cue signal according to the present invention is recorded in multi-track PCM recording.

2 shows a standard tape recording format (A) for 8 milli video and a tape recording form (B) when 8 milli video is converted to a multitrack PCM.

3 is a circuit block diagram for explaining an outline of PCM audio signal recording in 8 milli video.

4 is a detailed illustration of the PCM audio recording area in 8 milli video.

FIG. 5 is a diagram for explaining an example of a tape recording format in the case of dedicating 8 milli video to multitrack PCM audio recording.

6 is a circuit block diagram and a gas pulse waveform diagram for explaining the cue signal recording circuit.

FIG. 7 is a tape recording pattern diagram showing recording trajectories when audio tracks are recorded one track at a time. FIG.

* Explanation of symbols for main parts of the drawings

1, 6, 9, 13, 15, 16, 17: Terminal 2: AD converter

3: signal processing circuit 4, 5: random access memory

7: switch circuit 8,20: recording amplifier

10, 21: magnetic head 11, 22: preamp

12: head switch circuit 14: demodulation circuit

18: addition circuit 19: gate circuit

23: playback signal processing circuit 24: detection circuit

25 Inverter 26 Conductor wire (Gate positioning pulse)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of recording a cue signal or an address signal in each track in a device that divides an area in the width direction of a tape by a rotating head, for example, multitrack records a PCM audio signal. .

Background Art [0002] Conventionally, in a video tape recorder, a method of recording a cue signal for electronic editing or the like using a cue track formed in the longitudinal direction of the tape is well known.

However, as in the conventional method as described above, the method for forming a cue track in the tape length direction is a multitrack recording apparatus for a multitrack recording apparatus for multitrack recording PCM audio signals by dividing the area in the tape width direction. Since it is necessary to form as many as the number of tracks, the utilization efficiency of the tape becomes extremely bad. Accordingly, an object of the present invention is to provide a method of increasing the efficiency of multitrack tracking by using a rotating head to increase the recording time of a conventional multitrack track signal by a rotating head which is problematic.

The present invention provides a recording and reproducing apparatus in which a recording tape is wound obliquely around a rotating head cylinder to form a recording track inclined with respect to the tape longitudinal direction, wherein the recording track is divided into an area in the width direction of the tape. In an apparatus for recording n multitracks in the width direction of a tape, and recording information signals such as PCM audio signals in each track, a cue is placed at the rear end after recording of the information signals of each track of n multitracks. A method of recording a cue signal, characterized by recording a signal by a rotating head.

According to the method described above, for example, a post-nball signal inserted immediately after the end of the information signal of each track of a multitrack and a cue signal can be superimposed on the track guard area, and are not required for reproduction. The post and ball signal area can be effectively used as the cue signal area, and the cue signal can be recorded corresponding to each track of the multitrack, so that a cue track corresponding to each track needs to be specially formed as in the conventional method. Disappear. Further, the recording of the cue signal does not require a special recording head for the cue signal. In this way, the cue signal recorded by the rotating head preferably records a low frequency pilot signal. When the cue signal is a low frequency pilot, the tape is driven at high speed to facilitate playback even when the cue signal point is searched at high speed. However, in order for the cue signal point to be reproduced even during high-speed search, it is necessary to record the cue signal over a plurality of recording trajectories of each track of the multitrack. (It is usually sufficient to record between about 1 second.)

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 2 shows a tape recording format (equivalent drawing A) at 8 milli video and a tape recording format (e.g. drawing B) when multitrack PCM audio signal recording is performed without recording video signals using an 8 milli video deck. ) Is displayed.

In FIG. 2A, in 8 milli video, the tape is wound about 221 degrees around the rotational head cylinder, and the time-compressed PCM audio signal is recorded in a portion of about 36 degrees at the lower end of the tape. The video signal and the FM-modulated audio signal are recorded in the 180 ° + a ° portion. In addition, as a synchronization signal for the reproduction head to accurately reproduce the recording track image at the time of reproduction, a pilot signal of low frequency is superimposed on the video signal and the PCM signal and recorded on each track. The details are omitted since they are not particularly relevant to the purpose.) In addition, the cue signal tracks and the linear audio tracks are formed at the upper and lower ends of the tape as auxiliary tracks, respectively.

However, in the 8-milli-video tape recorder as shown in FIG. 2A, if only the PCM audio signal is recorded without recording the video signal, the time-compressed PCM audio signal in the region of 36 ° is obtained in six tracks as shown in FIG. Can form In an 8 milli video recorder with a built-in PCM audio recording and reproducing circuit, it is possible to easily switch to a deck for multitrack PCM audio recording and reproduction as shown in FIG. 2B by simply switching the recording phase of the PCM audio signal. . In the case of multitrack PCM audio recording in this manner, the main purpose is to provide a means for inserting a cue signal for each track, but an overview of PCM recording in 8 milli video is explained before explaining the cue signal insertion method.

3 is a circuit block diagram for explaining an outline of PCM audio recording in 8 milli video. In the figure, the audio signal input from the terminal 1 is converted into a 10-bit digital signal by the AD / DA converter 2 and compressed to 8 bits. The audio signal converted into a digital signal is inputted to the signal processing circuit 3, and an error correction code is added to the random access memory 4 and 5, for example, once alternately stored every 1/60 second, The information stored in the random access memories 4 and 5 is alternately read at high speed, modulated for recording, and then input to the switch circuit 7. In the switch circuit 7, a signal mixed with a video signal and an FM audio signal input from the terminal 6 and an output signal (hereinafter referred to as a PCM signal) of the signal processing circuit 3 are switched, and the pilot input from the terminal 9 is switched. Mixed with the signal, the recording amplifier 8 leads to the magnetic head 10 via the R side of the recording / playback switching switch SW to be recorded on the magnetic tape. At the time of reproduction, the signal reproduced from the head 10 is inputted to the preamplifier 11 via the P side of the recording reproduction switching switch, amplified, and then input to the head switch circuit 12. One of the outputs of the head switch circuit 12 is outputted with a video signal, an FM audio signal, and a pilot signal from the terminal 13, and the other is inputted to the demodulation circuit 14 of the PCM signal and returned to the original PCM signal. do. Thus, after inputting into the PCM signal processing circuit 3 again and correcting errors, the random access memories 4, 5 are alternately stored in the random access memories 4, 5, and the random access memories 4, 5 The stored data is read out and input to the DA converter 2 to obtain a demodulated reproduction audio signal from the terminal 15. Here, (2) indicates that the AD converter and the DA converter are to be recorded or reproduced, and the signal processing circuit is also switched to recording or reproduction. In the actual 8 milli-video, the audio signal before input to the AD converter passes through the compression circuit, and the DA output is input to the decompression circuit during reproduction, but is omitted here.

As described above, the circuit shown in Fig. 3 can be stored on the tape as shown in Fig. 2A, but the position at which the signal is recorded on the tape is determined based on the pulse representing the rotational phase of the rotating head. Therefore, if only the PCM audio signal is recorded without recording the video signal and the FM audio signal, and the phase of the rotation pulse is shifted by 36 degrees, the recording position of the PCM signal can be shifted and stored as shown in FIG.

However, if the format on the tape is displayed in the PCM audio signal recording in 8 milli video, it is as shown in FIG. In Fig. 4, (a) is a clock run-in with an angle of 2 ° or more, (b) is a data area, 26.3 °, and (c) is an after-recording margin and an angle of 2 ° (in this region a post-envelope carrier (D) is the videooverlap (about 2.7 °).

The clock run-in portion a actually holds 5 °, and the PCM area is about 33.3 ° in the region of ι.

Next, the recording area on the tape when multitrack PCM recording is performed will be described. 5 shows the recording area on the tape in the case of multitrack PCM recording at 36 ° per track. In the same figure, each track occupies 36 ° and can take a 5 ° margin behind the track 6. When each track is further enlarged, it is like the bottom view of FIG. 5, which is the same as FIG. 4, but in some others, the part of d (video or overlap) of FIG. 4 becomes the track guard (d ') in FIG. It is a part of the inorganic book.

The present invention records the cue signal corresponding to each track with respect to the multitrack PCM signal recorded in this way in the area of (c) or (d ') of FIG. 5 or the areas of (c) and (d'). will be. When a low frequency signal (for example, around 200 Hz) is recorded as the cue signal, stable reproduction is possible at the time of reproduction. (This will be described later). In addition, although the area | region of (c) of FIG. 4 and FIG. 5 is called after recording margin, it is not necessary to store an original signal in this area | region, and it is an unnecessary part at the time of reproduction | regeneration.

The meaning of the area of (c) is that if the new PCM signal is superimposed by the superimposition recording on the once stored PCM signal, the previously recorded area and the newly recorded area are recorded previously If the old signal remains, the previous residual data may be stored incorrectly when a new recording signal is reproduced, which may cause noise. Therefore, a clock of 5.8MHz (post (En bles), the above data is erased by the post envelop, especially during after-recording by overlapping memory. Therefore, even if the cue signal is stored in this area (c), no error occurs in the reproduction signal.

Therefore, the cue signal can be stored in the areas (c) and (d '), and may be stored only in part thereof. In extreme cases, the cue signal may be stored up to an area where (a) (clock run-in) of the next track becomes a minimum value (2 °).

The longer the recording area of the cue signal is, the more stable the detection is. However, if there is about one horizontal scanning period of the television signal, the detection can be sufficiently performed. Adding the areas of (c) and (d '), it is 4.7 °, and recording a cue signal of about 0.7 ° from a moving point is not a problem with machine precision.

As a method of accurately determining the cue signal recording position, a PCM signal is reproduced, the end portion of the PCM data (b) is accurately detected from the address signal detected from the reproduced PCM signal, and the detection signal is used as a reference. The method of designating the recording position of the cue signal can be selected.

6 shows a block diagram of a specific example of the write circuit of the cue signal and an explanatory waveform diagram thereof. In the same figure, the low frequency fk for the cue signal is input from the terminal 16, the bias signal fB for AC bias recording is input from the terminal 17, and it is added by the addition circuit 18, and is added to the gate circuit 19. FIG. Is entered.

Here, as the cue signal fk, a frequency component within a range sufficiently distinguishable from the tracking pilot signal (100 kHz to 160 kHz) is preferably a low frequency component of about 500 kHz to about 500 kHz. As the cue signal, an fs signal of about 230 Hz, which is standardized as a signal for head height matching at 8 milli-video, may be used. Here, the bias signal fB is added in the sense of bias writing the cue signal.

As fB, it is convenient to use a clock signal (5.8 MHz) for the PCM. In the gate circuit 19, a signal is output from the recording amplifier 20 for a period in which the cue signal recording position pulse output from the conducting wire 26 is High, and the cue signal is recorded through the head 21. At this time, SW1 and SW2 are turned on and off in synchronism with the gate pulse. When the gate pulse is high, SW1 is turned off and SW2 is turned on so that the head becomes the recording mode and the cue signal is recorded.

When the gate pulse is LOW, SW1 is turned on and SW2 is turned off to enter the playback mode. The reproduction signal is amplified by the preamplifier 22 and input to the reproduction signal processing circuit 23. The correct address signal of the PCM signal obtained by the reproduction processing circuit of (23) is input to the detection circuit 24, and the last position of the PCM data area is detected in the circuit of (24) on the basis of this correct address signal, On the basis of this detection signal, the gate pulse for specifying the cue signal recording position is output to the conducting wire 26. When the last position of the data area is reproduced by any of the correct addresses, the position of the random access memory can be accurately known by this. Therefore, the timing of the last address of this memory can be detected.

In FIG. 6, the gate positioning pulse 26 is shown in the case of detecting from the reproduction PCM signal. However, the gate positioning pulse 26 is more simply based on the pulse shifted by a predetermined position from the PG signal indicating the rotational phase of the head. You can also create a gate pulse. 6 shows a method of bias recording the cue signal as an AC bias, fB can be recorded without the bias signal.

In the above example, a method of recording a signal of 200 Hz to 500 Hz as a cue signal has been described. However, a method of recording a signal of 2.9 MHz corresponding to, for example, "O" of PCM data at the cue signal recording position described above. It is also possible. In this case, a digital detection method can be adopted by using the cue signal when " O " data is continuously detected by more than a specified number.

By the way, consider how long it is appropriate to record this cue signal in the tape length direction.

Since the cue signal is preferably detected when the tape is fast forwarded or rewound, it is necessary to record this length over the length of the tape. For example, consider the 8-milli-video deck, which is based on recording NTSC-type television signals. Since each track of the multitrack is intermittently recorded every 1/60 second, the cue signal is produced at the same speed as the recording time. Even during playback, it can only detect once every 1/60 second. Therefore, for example, when the tape is sent or rewound at a speed 30 times faster than at the time of recording, it may be impossible to detect if at least 30 cue signals are recorded in the tape length direction. Therefore, if safety is considered, it is preferable to record more than 60 cue signals. In order to record 60 cue signals, the cue signal recording time T in the lower figure of FIG. 6 becomes 1 second. At least 0.5 seconds or more as T is enough in this case to have a maximum of 2 seconds (it is not a problem even if T is made larger).

FIG. 1 shows the state when the cue signal is recorded in the track 2 of the PCM during the period T. Thus, the cue signal is recorded in the area (c) or (d ') of the track 2 indicated by the diagonal lines. It is.

In FIG. 1, when the cue signal is recorded only in track 2, the cue signal can be inserted at any position of each track from track 1 to track 6, and two or more cue signals can be inserted at the same position in the tape length direction. Even if the track cue signal recording positions overlap, there is no problem in detecting the cue signal recording positions. The length of T is not necessarily 0.5 seconds or longer, and only one place of recording the cue signal is used (that is, T = 1/60 seconds). It is impossible to detect only when the tape speed is lower than or equal to the tape speed. However, since the cue signal may be used for such a purpose, only one recording is meaningful.

In the above description, the multitrack PCM audio signal has been described in the case where the multitrack PCM audio signals are recorded in a straight line on the recording trajectory of the rotating head as shown in FIG. As described above, the sound tracks may be randomly selected for the scan trajectory of the head. In general, when recording is performed one track at a time, recording is performed randomly as shown in FIG. The reason for the recording as shown in Fig. 7 is that the tracking during playback is performed by using the tracking pilot signal recorded in superimposition with the PCM signal, and the track tracking is detected from the playback tracking pilot signal obtained for each audio track, and this detection signal is detected. This is because tracking can be performed for each track alone by sample-holding.

Also in Fig. 7, the case where the cue signal is recorded in the track 2 in the areas c and d 'is recorded in an oblique line.

In the above description, the cue signal recording method in the case of multi-track PCM audio recording has been described, but the after-recording margin of (c) in FIG. 4 also applies to the tape on which the PCM audio signal and the video signal are recorded as shown in FIG. When the cue signal is recorded in the recording section, the cue signal can be recorded and reproduced by the rotating head without using the cue track at the tape end.

For the reproduction of the cue signal, when using a cue signal of 200 Hz to 500 Hz, a band filter centered on the cue signal frequency fk is used at the position of approximately the head rotational phase of the designated reproduction audio track. It is possible to detect stably by detecting that fk is reproduced.

When the PCM data "O" signal is used as the cue signal, when the "O" information is digitally detected continuously by a reproducing clock made by the PLL (for example, 50), the cue signal cannot be used. have. In the case of digital recording, recording and reproduction of the cue signal including the address data can also be performed. If the cue signal has been recorded over the period T of FIG. You can also stop the tape.

In addition, the above description has been given of an example in which the driving direction of the tape is in only one direction. For example, in an odd track, an apparatus such as recording and reproducing with the tape running in the left direction and the even track in the right direction may be used. Also, the conditions for the cue signal recording and reproducing are the same.

According to the present invention, the following effects can be obtained.

(1) During multitrack PCM audio recording, the cue signal can be recorded on the recording completion tape of the PCM signal at an arbitrary tape length position for each track, so that the cue signal can be recorded without adversely affecting the signal of the recording completion tape. Can record at random

(2) Since the cue signal can be recorded and reproduced using the rotation head for PCM signal recording and reproduction, there is no need to use a fixed head for the cue signal or the like.

(3) Since the cue track does not need to be newly formed for each voice track, the tape utilization efficiency is good. Other benefits associated with this are conceivable.

Claims (4)

Time-compression PCM audio signal by sequentially forming inclined recording scan traces (FIGS. 1), (FIGS. 2), and (FIG. 7) on the tape of the rotating head helical scanning magnetic recording and reproducing apparatus. (Track 3), and record a plurality of tracks (track 1), (track 2), (track 3), (track 4), (track 5), and (track 5) in the width direction of the tape. 6) A device for dividing and recording, in which a cue signal is recorded in a tape length direction (V _T direction) at an arbitrary position of any of the plurality of tracks, and the PCM data signal (b) of the track. A cue signal recording method, characterized in that the after-recording margin portion or track which is continued immediately after is made to record the cue signal over a portion (c or d '), or (c and d') of the ad portion. The cue signal recording method according to claim 1, wherein the cue signal is recorded over a plurality of head scan trajectories. The cue signal recording method according to claim 1, wherein the cue signal recording timing is generated based on the head rotational phase detection pulse. The cue signal recording method according to claim 1, wherein the cue signal is generated based on a signal (26) of detecting the last position of the reproduction PCM data.

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