JPS6276043A - Information signal recording device - Google Patents

Abstract

PURPOSE:To attain the recording in matching with a recorded information signal independently of the moving speed of a recording medium by bringing an FEH in the reproduction mode so as to detect the recording state of a recording medium thereby controlling the operation start timing of a recording head. CONSTITUTION:A reproducing pilot signal is extracted by a LPF 25, a signal f' is multiplied with the result as a local pilot signal, the result is fed to a BPF 27 passing through a signal 2fH only and to a BPF 28 passing through a signal fH only, and after the outputs are detected by detectors 29, 30 respectively, the result is fed to a differential amplifier 31 to form a tracking error signal. When ahead is at a position 21a and deviated at the track side even a little toward the track recorded with the signal f1, since the 2fH component in the output of the multiplier 26 is increased more than the fH component, the level of the tracking error signal gets higher. Thus, the running speed of a tape is quickened attended therewith and the trace position of the head is being deviated toward the track on which the signal f1 is recorded. Finally, the trace position is shifted up to the position 21b and made stable.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an information signal recording device equipped with a rotating recording head and a rotating erasing head (hereinafter referred to as flying eraser) (FEW). .

[Conventional technology]

Conventionally, when an information signal is recorded by a rotary head, a control head (CTL head) records a control signal (CTL) on a track formed in the longitudinal direction of a tape-shaped recording medium. In the signal recording and reproducing apparatus, the timing of starting recording is determined by measuring the reproduced CTL signal during so-called continuous recording.

On the other hand, in a recording/reproducing device that performs tracking using a so-called four-frequency method, a means different from that used in a device that performs tracking using CTL must be used.

[Problem that the invention seeks to solve]

VTRs that adopt a 4-frequency system, such as the well-known 8
In the rtrm VTR, there is a mode (hereinafter referred to as SP) in which recording and playback is performed by running the tape at a standard speed.
), a mode in which the tape runs at ten times the speed of SP (hereinafter referred to as LP), a mode in which the tape runs at ten times the speed of SP (hereinafter referred to as EP), etc. When performing so-called splicing, if the tape speed is changed, it is difficult to determine the timing to start recording. In other words, when splicing shots as is commonly done, if you rewind the tape by an amount corresponding to a predetermined number of tracks, and then start recording at the timing when the tape has run for that number of tracks, the information that has already been recorded will be lost. There is a problem in that the recording positions of information signals cannot be properly connected because the data may be erased or unrecorded portions may be created.

This invention was made in order to solve this problem, and is an information signal recording system that can perform consistent recording of recorded information signals regardless of the moving speed of the recording medium during recording. The purpose is to obtain equipment.

[Means for solving problems]

The information signal recording device according to the present invention includes an FE that traces a position preceding a recording rotary head on a recording medium.
The apparatus is provided with means for detecting the reproduction output of H, and means for controlling the recording operation start timing of the recording head based on this detection means.

[For production]

In this invention, the FEH is set to regeneration mode and the FEH is
By detecting the reproduction output of H, the recording state of the information signal on the recording medium is detected, and the operation of the recording head can be started in a state consistent with the recorded information signal.

〔Example〕

FIG. 9 is a diagram showing a recording magnetization locus of a VTR that performs tracking using a four-frequency system, and FIG. 10 is a block diagram showing the main part of a conventional tracking error signal processing circuit.

In FIG. 9, numeral 1 indicates a magnetic tape, and arrow 2 indicates the direction in which the magnetic tape 1 is transported.

AI HB+ HA2+ Bx g... are recording trunks recorded by the A head and the B head, each having a predetermined azimuth angle with respect to each other, and arrow 3 indicates the scanning direction of the heads. Recording track 4 contains 4 along with video signals.
Pilot signals having different types of frequencies (indicated by fl to f4) are sequentially recorded for each field (that is, for each track). The recording order of the pilot signals is V order as shown in FIG.
ls e.g. 6.5fa in 102.5KHz, ) rank B1 has f2, e.g. 7.5 fH in 118.9KHz
,) Rack A2 has f3, for example 165.2KHz=
10.5 fH1 track B2 has f4, e.g. 14
A pilot signal of 9.5 fH in 8.7 KHz is superimposed on the video signal and recorded. (Note that fH indicates the frequency of the horizontal synchronizing signal.) The frequency difference of the pilot signals between adjacent recording tracks is f'H or 3fH as shown in the figure. When the head scans the track A i (l''L 2+3 . . . ), the frequency difference with the pilot signal of the adjacent track on the right side of the figure is always fH, and the frequency difference with that on the left side is always 3fH. In addition, the head is Bi (i=1.2
．． 3...) When scanning a track, the frequency difference with the adjacent track on the right side is always 3fH, and the frequency difference with the adjacent track on the left side is always fH.

Incidentally, since the pilot signals f1 to f4 are all comparatively low frequency signals, even in azimuth recording, the head can reproduce the pilot signals from adjacent tracks other than the main scanning trunk as crosstalk. That is, the pilot signal detected when the head is main scanning the track A2 is f<.

f2. f is a composite signal containing each frequency component, and when the center of the trace trajectory of the head exactly coincides with the center line of the main scanning track (on-track), the pilot signal of the adjacent track f2. If f4 is at the same level and the head slightly shifts from track A2 to track B2, f4 becomes f2.
thicker (and the head is slightly B+ from track A2)
If it shifts to the side, f2 is reproduced larger than f4.

Therefore, the signal of the difference between the pilot signal on the main scanning trunk and each pilot signal of both adjacent tracks, that is, fH and 3fH
By separating and extracting the signals and comparing the levels of both difference signals, the direction and amount of deviation of the head from the main scanning trunk can be determined.

FIG. 10 is a circuit block diagram of such a four-frequency system.
)6, only the pilot signal component is separated. A multiplier 8 multiplies the pilot signal component by the local pilot signal generated by the generating circuit 7. The local/milot signal is a signal of the same frequency as the pilot signal recorded on the main scanning track, and as described in the explanation of FIG. 9, if track A2 is the main scanning trunk, the output of the LPF 6 is f2. The frequency of the local pilot signal is f, including f4° f3 components. Therefore, the output of multiplier 8 is f2. A signal having a frequency of the sum and difference of f4° f3 and f3 is output. A bandpass filter (BPF) 9 is a circuit that extracts only fH from the sum and difference signals, and BPFIO is a circuit that extracts only a 3fH signal.
These outputs are detected and rectified by detection circuits 11 and 12 at the next stage, respectively.

Next, the fH signal component and the 3fH signal component are supplied to a level comparison circuit 13, which outputs a signal corresponding to the level difference between them. That is, f.

When the reproduction level of the 3fH signal is higher than the reproduction level of the 3fH signal, a positive potential corresponding to the level difference is extracted, and in the opposite case, a negative potential is extracted. As a result, a signal containing information on the amount and direction of head trunk deviation is output, and this can be used as a tracking error signal.

Next, as explained in FIG. 9, the relationship between the head deviation direction tracking error signal and the trunk A1 and the trunk B+ will be opposite to each other if this continues. It is necessary to provide a switching circuit 16 that selectively outputs what passes and what does not pass using the head switching signal 15.

FIG. 1 is a circuit block diagram as an embodiment of the present invention, in which 25.34 is a low-pass filter (LPF), 26
is a multiplier, 27 and 28 are band pass filters (BPF)
, 29, 30.35 are detectors, 31, 36, 37 are differential amplifiers, 32 are analog switches, 33 are amplifiers, 38
, 39 is a delay circuit, 40 is an OR circuit, 42 is a flip-flop, 43 is an 8.5 fH local pilot signal generator, 114 is a tracking error signal processing circuit in SP mode at normal tape speed, 45 is a capstan. This is a motor drive circuit.

In addition, Fig. 2 (■) is a diagram showing the head arrangement of the VTR according to the embodiment of the present invention, and Fig. 3 is a diagram showing the state of playback by the VTR of this embodiment. This head is mounted on the rotating drum 23 with a phase difference of 180°.

In addition, 24 is FBI (and is attached with a phase difference of 90 degrees with respect to heads 21 and 22. Also, when the track pitch in SP mode is TP, approximately 2.5Tp on the rotating drum 23 Accordingly, the position shifted by TP during recording and playback is traced.The state of this tape trace is shown in FIG.

In FIG. 3, the recording and reproducing heads 21 and 22 are SP
Since the head N (iIi) is determined so that recording and reproduction can be performed in the 'FM number mode of the LP mode, a recording pattern with a guard band is used in the SP mode.

Next, the principle of continuous shooting in this embodiment will be explained.

Now, while tape 1 is running in tape traveling direction 2, while recording in LP mode, there is a pause (
Pause) input is input, and the VTR enters the recording pause (Re
c pause) state. The tape pattern at that time is shown in FIG. 4, but it is assumed that when recording is stopped, it always ends at field f4. Now, after the recording pause key is manually performed, the so-called record review (Rec
The tape is run in the reverse direction, rewound a little, then stopped, and enters a recording pause state, waiting for the next manual key operation. In this state, when the pause release key is pressed manually, the tape runs in the normal direction, and when it passes through an area that has already been recorded, the heads 21 and 22 do not record, but only when they reach an unrecorded area. The idea is to start recording.

In this embodiment, a case will be described below in which the recorded information signal is recorded by changing the running speed of the tape, especially during continuous shooting.

First, in the pattern recorded in LP mode,
The case of continuous shooting using P mode will be described.

When the tape is running at the speed determined by SP mode, if signal processing is performed using the normal 4-frequency method, a tracking error signal will not be obtained for the pattern recorded in LP mode, and the capstan servo It doesn't cost much. Therefore, as shown in FIG. 6, four frequencies fl,
In addition to f2°fl and f4, consider a pilot signal f' of 8.5 fH (fH=horizontal synchronization frequency).

As shown in FIG. 6, if f' is a local pilot signal, the multiplication output of the regenerated pilot signal and the local pilot signal includes a 2fH component when fl,
When it is f4, rice components are included.

Further, the heads 21 and 22 described above always pick up two types of reproduced pilot signals within one field period even when a pattern recorded in the LP mode is reproduced in the SP mode.

Now, as shown in No. 11N, the regenerated pilot signal t-L
B P F is extracted by PF25, multiplied by f' as a local "pilot signal, and only 2fH is passed.
27 and BPF 28 which allows only fH to pass through, these outputs are further detected by detectors 29 and 30, respectively, and then added to a differential amplifier 31 to be used as a tracking error signal. Here, when the head is at the position 218 as shown in FIG. 4, it approaches the position 21b or 21C.

This is because when the head is in the position shown in 21a, even a little f
If the tracking error signal deviates to the track side where l is recorded, the 2fH component in the output of the multiplier 26 becomes larger than the fH acid component, so that the tracking error signal level becomes high. As a result, the tape travels 7 degrees faster, and the head trace position further shifts toward the track where f is recorded. Finally, the trace position shifts to the position shown at 21b in the figure and becomes stable.

On the other hand, if the head deviates even slightly from the position shown in 21a to the track side where f4 is recorded, in order to slow down the tape running speed, the head trace position is further moved to the rack side where f4 is recorded. The trace position gradually shifts, and finally the trace position shifts to the position shown by 21e and becomes stable.

In other words, if the tracking control during continuous shooting according to the embodiment is performed, the tracking will be stabilized with the heads 21 and 22 straddling the tracks on which fl and f2, or f and f4 are recorded, and f2, fl, and fl. It will not cross over the f4 track.

When the Rec pause is released, if a high level (High) is input to the terminal 41, the Q output of the flip-flop 42 is set to The above-mentioned tracking is performed as a signal.At this time, the FEH 24 is set to the reproduction mode, and during the reproduction output via the amplifier 33, the LPF 34 cuts off high frequency components and the signal is passed to the detector 35.

If the FEH24 is tracing the already recorded part, the reproduced signal can be obtained from the FEH24, so
The outputs of the differential amplifiers 36 and 37 are both low level (Low
). After that, if the tape is moving while FEB is in playback mode and tracking as described above,
The FEB traces the unrecorded portion, and the positional relationship of each head at this time is as shown by solid lines in FIG. 4 or FIG. 5.

In the case shown in FIG. 4, the head 21 is at the position shown in 21a and tracking is achieved, and at this time, the FEH
The full width of 24 traces the unrecorded portion.

Therefore, assuming that the threshold voltage is El, when the state shown in FIG. 4 is reached, the outputs of the differential amplifiers 36 and 37 both become High. The phase relationship between the head 21 and the FEH 24 is as shown in FIGS. 2 and 3, but it takes 1.5 field periods from the state shown in FIG. 4 until the head 21 starts tracing the unrecorded area. Therefore, if the heads 21 and 22 are placed in the recording mode using a signal that is delayed by 1.5 fields from the output of the differential amplifier 36, a smooth transition is completed.

Further, as shown in FIG. 5, when the head 21 is at f3. When tracking is achieved while straddling the trunk where f4 is recorded, when the FEH 24 detects an unrecorded portion, the unrecorded portion spans half the width of the FEH 24. Therefore, in FIG. 1, if the corresponding threshold voltage is set as E2, the differential amplifier 3
Only the output of 7 is LOW) (i g h rises. In this case, if the recording mode is set after 2.5 fields, a clean connection will be completed, so the differential amplifier 37
It is sufficient to set the recording mode by delaying the output by the delay circuit 39 by a period of 2.5 fields.

Then, as shown in FIG. 4, when the head 21 has previously been able to track f, f and f2, and the full width of the FEH 24 covers the unrecorded area, or as shown in FIG.
When the head 21 has previously tracked fs and f4 and the unrecorded portion spans half the width of F E H 24, the output of the differential amplifier 36 or 37 is of course After the 1.57 yield period or during the 25 field period, the 7 limp flop 42 is reset through the OR circuit 40, and the Q output of this flip flop 42 becomes LOW, and as a result, the analog The switch 32 is turned off and normal tracking signal processing begins.Furthermore, the output of the OR circuit 40 is supplied to a system controller (not shown) from a terminal 46, and the heads 21 and 22 enter the recording state to start smooth continuous shooting. will be done.

FIG. 7 shows a timing chart of the operations of the flip-flop 42, differential amplifiers 36, 37, and delay circuits 38, 39 in FIG. 1.

The above explanation describes the case of splicing a pattern recorded on an LP using SP, but the present invention is also applicable to splicing when recording is performed at the same tape speed as the recorded track. The effect of this can be obtained.

FIG. 8 shows a situation where splicing is performed at SP when recording tracks are recorded at SP. In this case, the local pilot) signal f is the same as normal playback.
, f2w f31 r4 and tracking can be done sequentially, so be sure to use the 8th one at the joint.
The phase relationship shown in the figure is obtained.

Therefore, if the recording is switched to 1.5 fields after the detection output of the reproduction output of the FEH 24 falls below the threshold voltage E1, a clean transition will be completed.

Also, when replacing LP with EP, etc., F
Using the EH playback signal, smooth continuous shooting can be achieved.

〔Effect of the invention〕

As explained above, this invention is provided with a means for controlling the operation start timing of the recording head by setting the FEH to the playback mode and detecting the recording state of the recording medium. It is possible to obtain an information signal recording device that can record recorded information signals in a consistent manner regardless of the moving speed.

[Brief explanation of drawings]

1 is a circuit block diagram of the main parts of a VTR according to an embodiment of the present invention, FIGS. 2(a) and 2(b) are diagrams showing the head arrangement of the VTR shown in FIG. 1, and FIG. 3 is a diagram similar to that shown in FIG. 1. FIG. 4 is a diagram showing tape tracing by a VTR. FIG. 5 is a diagram showing the state of tape tracing during continuous recording, FIG. 6 is a diagram showing the frequency relationship of signals used in the embodiment of FIG. 1, and FIG. 7 is a diagram showing the timing of each part in the embodiment of this invention. Figure 8 is a diagram showing the state of tape tracing during continuous recording, Figure 9 is a diagram showing the recorded magnetization locus of a VTR that performs tracking using the four-frequency method, and Figure 10 is a conventional tracking error signal processing circuit. FIG. 2 is a block diagram showing the main parts of. In the figure, 1 is a tape as a recording medium, 21°22
is a recording head, 24 is an FEH, 25 and 34 are low-pass filters (LPF), 26 is a multiplier, 27.28 is a band-pass filter (BPF), 29°30.35 is a detector, 31, 36.37 is a differential amplifier, 32 is an analog switch, 33 is an amplifier, 38° and 39 are delay circuits, 40 is an OR circuit, 42 is a flip-flop, 43 is a local pilot signal generator, 44 is a tracking error signal processing circuit, 45 is a drive It is a circuit. Agent Patent Attorney 1) Haru Kitatake Figure 2 (a) Figure 2 (b) Figure 3 Figure 4 Figure 5 Figure 7

Claims (1)

[Claims] In an information signal recording device equipped with a rotary head for recording and a rotary erasing head for tracing a position preceding the rotary head on a recording medium, the rotary erasing head is placed in a playback mode and the rotary erasing head is An information signal recording apparatus comprising: means for detecting reproduction output; and means for controlling a recording operation start timing of the recording head based on the detecting means.