JPS6212945A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent an error erasion from occurring by providing an error erasion signal recording area corresponding to divided tracks in the extremely outer longitudinal track and discriminating the existence/absence of a recording of signal. CONSTITUTION:The titled device is so constituted that a magnetic tape is wound spirally around a cylinder incorporated a rotary head, information signals are recorded in a discontinuous group of recording tracks, and one scanning track is divided into plural tracks, and the recording and reproducing of the informa tion signals are executed respectively from the said divided racks. The track is provided in the outer end of the magnetic tape in the longitudinal direction. The said longitudinal track is divided slantingly by a fixed length. Assuming the number of the divided tracks for recording to be N, in every (N+1)th divi sion, a first frequency is recorded. And, a second frequency is sequentially recorded in ones corresponding to the slant recording division in which recording is recorded. A reproduction head is so provided as contacting these divisions before a recording head does. When the second frequency is reproduced by the reproduction head, the recording in the slant recording divisions is prohibited.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention divides a diagonal track of a magnetic recording/reproducing device (hereinafter referred to as VTR) into a plurality of tracks, and records and reproduces information on each divided track. This invention relates to preventing accidental erasure of each track in a device.

Conventional technology Conventionally, audio compact cassette and VH8 system VT
There is a widely used method for detecting whether or not the magnetic tape stored in the tape cassette has already been recorded, based on whether or not there is a recess in a specific part of the rear of the tape cassette. It was used.

Problems to be Solved by the Invention However, as disclosed in, for example, Japanese Unexamined Patent Publication No. 58-222402, the recording track of a helical scan type magnetic recording/reproducing device is divided into a plurality of tracks, and each division is In a device that records and reproduces an information signal for each recorded track, it was not possible in the prior art to obtain information as to whether information has been recorded or not. In view of this, an object of the present invention is to provide a device for obtaining information on whether or not each track has been recorded.

Means for Solving the Problems The present invention provides a track along the longitudinal direction of the tape at the end of the tape in addition to the divided diagonal tracks, and divides the track into one track out of the number N of divided diagonal tracks. many,(
N-)-1) Divide into sections of a certain length and make N pieces correspond to each of the diagonal tracks, so that when recording on the diagonal tracks, it is also recorded on the trunk portion in the corresponding longitudinal direction. Otherwise, a longitudinal track playback head is provided in a portion of the longitudinal track where the tape runs ahead of the recording head, and the determination is made based on whether or not there is a playback signal on the playback head.

Function: As mentioned above, erroneous erasure signal recording areas corresponding to the divided tracks are provided in the longitudinal tracks at the end of the tape, and erroneous erasure is prevented by determining whether or not a signal is recorded in that area. do.

Before detailed explanation of the embodiment invention, we will explain Japanese Patent Application Laid-Open No. 58-222402
The multi-track PCM described in the publication will be briefly explained. Figure 4 shows the tape format when using 8ξ revideo as a multi-track POM.
1.1 indicates the video tape, 2 indicates the tape running direction, 3 indicates the scanning direction of the rotary head, 4 indicates the second optional track for recording audio signals, and 5 indicates the first optional track for recording cue signals. . BL2-mu1. BL3
-Music 1 to BL6-Person 1 is the trunk section normally used to record video signals, and BLl-Mu 1 is a signal that converts the audio signal to a PCM signal and further compresses the time to about one-fifth. This is the track for recording. multitrack pcm
When used as a video signal, the track on which the previous video signal is recorded is divided into six equal parts. That is, for each source, BLl
-mu1, BLl-B1, BLl-mu2.・・・・・・
・Record. FIG. 5 is a plan view showing the main parts of the tape running system for realizing the tape pattern shown in FIG.
Similar to FIG. 4, arrows 2.3 indicate the direction of tape travel and the direction of rotation of the rotating head. The tape is wound around the cylinder 6 which has a built-in rotary head 7.8, in addition to the conventional wrapping of approximately 180 degrees, the tape is wound approximately 36 degrees more (BLl-m 1) corresponding to the PCM recording area. It is.

The object of the present invention can be achieved by recording or detecting an erroneous erasure signal on the first or second option track in FIG. 4 using the method described below.

Figure 6 shows the head for recording and reproducing the accidental erasure prevention signal used in the present invention, in which the reproducing head and the recording head are separate heads), 1 is the tape, 2 is the tape running direction, 9 1 is an erroneous erasure signal reproducing head, and 10 is an erroneous erasure prevention signal recording head.

When the first option track is an erroneous erasure prevention signal recording track, 11 indicates a reproduction gap and 12 indicates a recording gap. The head b has a double gap of a read gap 11 and a write gap 12. The distance P between the playback gap and the recording gap is the tape speed Vt (t
rttt/sec), the number of divisions N, the recording time t1 of one accidental erasure prevention signal, and the natural number n, P:VtX
It is expressed as (t,)X(N-1-1)Xn.

Next, one embodiment of the present invention will be described using the electrical block diagram shown in FIG. 1 and the timing charts shown in FIGS. 2 and 3.

Whether or not each track has been recorded is determined by the recording position of the first frequency f for the identification marker and the second frequency f2 indicating whether or not each track has been recorded, as shown in FIG. 2 (0). The determination is made based on the position where the f2 signal is recorded relative to the position where fl is recorded.

First, the case of recording on the second track (part BL2 in FIG. 4) of a blank tape will be explained. The signal reproduced from the reproduction gap 11 is input to the reproduction amplifier 15 and amplified, and then passed through the f1 band pass filter (hereinafter referred to as BPF) 1.
6 and f2BPF17. f, B P F
The signal that has passed through the 1θ and f2BPF 17 is supplied to a detection rectifier circuit 18.19, converted to DC, and supplied to a Schmitt circuit 20.21. Since a blank tape is currently being played back, the Schmitt circuits 20 and 21 naturally output low level signals at the times shown in (&) and (b) in FIG.

Since the output of the first Schmitt circuit 20 is Low,
The output of the pulse generation circuit 22 is also low, and the output of the retriggerable multiplier 23 is also low, which is supplied as a high level signal to the AND circuit 34 via the shifter circuit 42. The output of the second Schmitt circuit 21 is output to the D terminal of the D-flip-flop 28. On the other hand, the output of a head rotational phase detector (not shown) is input to the head switch signal generation circuit 24 from an input terminal 41. The output of the head switch signal generating circuit 24 (FIG. 2g) is input to the neck divider 26. In the frequency dividing circuit 25, the head switching signal shown in FIG. 2g is inputted, and the head switching signals shown in FIG.

Signals f, h, i, and j are created, and a signal ev fs h+ i+ ] + k is supplied to the track select circuit 26. The output signal d of the collar frequency dividing circuit is supplied to an AND circuit 34. Among the signals '+f+h+i+]+k inputted to the track select circuit 26, the signal corresponding to the track designated for recording is selected as the second one.
Since the track has been specified, system control circuit 2
9 sends a signal specifying the second to the track select circuit 26, so the signal f is output. The f signal output from the track select circuit 26 is sent to the gate circuit 35. OR circuit 38 and sample pulse creation circuit 2
7. The sample pulse generation circuit 27 operates a mono multivibrator with a time constant of
Output to the clock terminal of 8. That is, the output of the mono-multivibrator is as shown in Fig. 2g. Since a signal at the L□w level is input to the D terminal of the flip-flop, the output is low, and a signal at the Lovr level indicating non-recording is output to the system control circuit 29.

On the other hand, an oscillator 30 that oscillates at a frequency that is a common multiple of f1 and fl.
The oscillated signal is frequency-divided by frequency dividers 31 and 32, and outputted as a sine wave signal through a filter (included in divider 31 and 32). The output of the frequency divider 31 is supplied to a first gate circuit 33. The first gate circuit 33 is A
The fl signal passes only when a Hi (h level signal) is supplied from the ND circuit 34.
The signal is passed only when the output d of the inverter circuit 42 is High and fl is a signal indicating that no recording is performed, that is, the output of the inverter circuit 42 is High. Therefore, a signal as shown in FIG. 2 is now output. The signal fl passes through the second gate circuit 36 only when the output of the channel select circuit 26 is High. The output of the second gate circuit 35 is a signal as shown in FIG. 2m. In the synthesizer 36, the output of the first gate circuit 33 and the output of the second gate circuit 35 are temporally synthesized and outputted as the signal shown in FIG. 2m. The output of the 9-synthesizer 36 is supplied to a recording circuit 37, and after being amplified, a bias signal is added and supplied to the switch 4o. Switch 4o 0
N-OFF is controlled by the output of AND circuit 39. AND circuit 39 receives a recording OK signal from the system control (corresponds to the signal from D-7 lip-flop 28)
is at High level, and the output of OR circuit 38 is High.
h, the output signal of the recording circuit 37 flows through the recording gap 12 and is recorded on the tape.

Next, a case will be described in which an attempt is made to record on the second track where data has already been recorded on the second track as described above.

The signal reproduced from the reproduction gap 11 and amplified by the reproduction amplifier 15 has f, Bpy 16. The signal is supplied to the f2BPF 17 and outputs the signals p and q in FIG. 3, respectively.

The signal p is input to the first Schmitt circuit 2o via the detection rectifier circuit 18, and the output is a signal as shown in FIG. 3r. The output (r signal) of the first Schmitt circuit 2o is supplied to the pulse generation circuit 22, which generates a pulse as shown in FIG. . The pulse supplied from the pulse generating circuit 22 to the y frequency dividing circuit 26 operates as a recent Hals, so that the phase where 11 was previously recorded becomes d in FIG. 2 (also d in FIG. 3). The retriggerable multi 23 operates based on the input pulse, and its delay time t2 is tlx (N-)-1) (t2(t
, x (N+1)X2. The output of the retriggerable multivibrator 23 becomes High, becomes Low in the inverter circuit 42, and is input to the ND circuit 34, thereby prohibiting the f1 signal from passing through the gate circuit.

Similarly, the output of the second Schmitt circuit 21 is also input to the D terminal of the D-flip-flop 28, as shown in FIG. 3f. Therefore, the output of the D flip-flop 28 is High.
and is supplied to the system control circuit 29.

Upon receiving this signal, the system control circuit 29 performs a recording inhibiting operation and also outputs a recording inhibiting low level signal to the AND circuit 39. Therefore, it is possible to prohibit additional recording to an already recorded location.

Next, a case will be described in which data is recorded on the fourth track on a tape that has already been recorded on the second track. Since it has already been recorded as described above, the output of f and the BPF 16 is as shown in FIG.
W level is supplied, and the output of the A frequency divider circuit 25 is also connected to the output of the first Schmitt circuit 20 and the A frequency divider circuit 26.
Therefore, the signal d supplied to the circuit 34 has the same timing.

Also, the output of the second Schmitt circuit 21 becomes the output t of the sample pulse generator 27 as shown in Fig. 3f, so D-7
The output of the lip-flop 28 is a low level tonal. Therefore, a LOW level recording permission signal is output from the system control circuit 29 to the ND circuit 39. Therefore, the output of the synthesizer 36 is U in FIG. 3, the output of the AND circuit 39 is also the main signal, and the U signal is recorded on the tape.

Also, the overwrite permission switch is set in the system control circuit 29.
is connected, and the output of the D-flip-flop 28 is High.
Of course, it is possible to avoid issuing a prohibition command for recording on diagonal tracks even if the data is recorded on a diagonal track. In addition, if it is possible to record and reproduce a part of the multi-track while moving the tape backwards, the recording gap and the reproduction gap are connected in reverse, and the system control circuit 29 connects the track select circuit 26. If the output designation is around 1, it will be 1 if it is in the opposite direction, 6 if it is in the opposite direction, 5 if the forward direction is 2, if it is running backwards, and so on. It is amazing that it can be used even if the divided tracks are recorded in both forward and reverse directions.

Effects of the Invention By using the present invention, as explained above, it is possible to prohibit recording over the previously recorded portion of each track of a multi-track POM device, and its practical value is great. .

[Brief explanation of the drawing]

FIG. 1 is an electrical block diagram of one embodiment of the present invention, and FIG.
Figure 3 is a timing chart for supplementary explanation of Figure 1, Figure 4 is a table turn diagram of multi-track PCM in 8mm video, and Figure 6 is for realizing the pattern in Figure 4. A schematic plan view of the tape running system of
FIG. 6 is a perspective view showing a head used in the present invention. 16.17...BPF, 18.19...
・Detection rectifier circuit, 20.21... Schmitt circuit, 26... frequency divider, 28...D-
7 lip flop. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Ilr□ Chil Chiz fz fz Chiz f
z chiz ft fz suz fz
BL-I BL-Z BL-3&-4βL-5BL-
6BL-/ BL-Z BL-3 Fig. 3 (It-) Fig. 5 7B--One rotation head F1 rotation Eye wheel direction - Direction Fig. 6

Claims (3)

[Claims] (1) Magnetic tape is wound diagonally around a cylinder with a built-in rotary head, and information signals are recorded as a group of discontinuous recording tracks.In addition, one scanning track is divided into multiple tracks, and the information signal is recorded on each divided track. In addition to being configured to perform recording and reproduction, a track is provided at the end of the magnetic tape along the longitudinal direction of the tape, and this longitudinal track is divided into sections of a constant length, where N is the number of divisions of the diagonal tracks, and
The first frequency is recorded every (N+1) number, and the second frequency is sequentially recorded in the corresponding part every time the diagonal track is recorded in the next divided part where the first frequency was recorded. 1. A magnetic recording and reproducing apparatus, characterized in that a reproducing head is provided in front of the head so as to come into contact with the tape, and when a second frequency is reproduced by the reproducing head, recording on an oblique track is prohibited. (2) The magnetic recording and reproducing apparatus according to claim 1, further comprising a switch for permitting overwriting of recorded tracks. (3) When recording some of the divided tracks in the reverse direction of the tape, the recording gap is used as a playback gap, and the playback gap is used as a recording gap. The magnetic recording and reproducing device described in .