JPS61280059A - Control pulse recording circuit of magnetic recording and reproducing and reproducing device - Google Patents

Abstract

PURPOSE:To shorten the delay time of a delay circuit and to reduce the influence of variance in temperature characteristics, etc., by recording control pulses at the delayed timing of a vertical synchronizing signal. CONSTITUTION:The output signal A of an oscillation circuit 3 is delayed by a time tSP through a monostable multivibrator 31 in SP mode to obtain a signal (f), which is shaped by a waveform shaping circuit 4 into control pulses (g). In EP mode, on the other hand, the signal A is supplied to the waveform shaping circuit 4 as it is and shaped into control pulses (h). Thus, a mechanical X value is normalized in neither SP or EP mode and deviation in X value due to the position adjustment of a control head in SP mode is corrected electrically by using a delay quantity like tSP=(P/A)XTO. Consequently, the delay quantity is small, there is almost no problem even if the delay quantity varies with temperature characteristics, and a variable resistor for adjustment is unneeded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a control pulse recording circuit for a magnetic recording/reproducing device, and more particularly to a device for recording control pulses in a double gap type magnetic recording device.

Conventional technology: In the so-called double-gap magnetic recording/reproducing device,
During recording and normal playback, as shown in FIGS. 5 and 6, in the standard play mode (SP) (2 hour mode), the video head 5P (1).

Expand play mode (EP) using SP ■
(6 hours mode) is video head EP (1).

Use EP■. The video heads EP2 and 5P(1) are mounted, for example, two days apart on the circumference of the rotating drum.

Here, for still playback in SP mode, video heads EP■ and SP■ with the same azimuth angle are used, and for still playback in EP mode, video head EP(1) with the same azimuth angle is used.
, using SP(1). By doing so, it is possible to perform field still in both SP mode and EP mode, which has a high reproduced FM level during still and has less blur than frame still.

On the other hand, regarding the recording control pulse, xi is specified in order to ensure compatibility of magnetic tape, and
As shown in the figure, when the video head of the first channel comes to the entrance of the magnetic tape, the control head records control pulses on the magnetic tape. For example, in SP mode, the control head can be replaced with a regular
If adjusted to the value position, the video head SP in EP mode.
There is a possibility that the X value will deviate due to the relative height between the video head SP and the EP. For the PG pulse, the recording timing of the recording control pulse in SP mode and EP mode is set by one field (
16,7a+5ec) It is necessary to shift.

However, the actual relative height C1 between video heads SP■ and EP(1) is different from the ideal relative height Go when optimally designed for slow playback, slow motion playback, or rotating audio heads. If P is the difference from the ideal height Co for the X value, then P=Co −C+.

Therefore, it is necessary to adjust the X value in SP mode and EP mode, but since there is only one control head, HII adjustment is generally performed in SP mode. First, in self-recording/playback, the preset volume connected in series with the tracking volume in the tracking monomultiple is adjusted so that the same track as the recorded track is played back. Next, using a standard tape (a tape recorded with a regular X value), the control head is adjusted so that the tracking volume is at the center position and the reproduced FM level is at its maximum. For example, when performing Xvi adjustment in EP mode using a standard tape for EP mode, it is difficult to adjust the four alignment positions of the control head to 1/3 the accuracy of SP mode.

Therefore, in the SP mode, the position of the control head is adjusted to obtain the normal X value, and in the EP mode, the X value is electrically corrected based on the relative height C1. That is, as shown below, in the conventional circuit, in the SP mode, the control head was adjusted to the normal X nail position and the control pulse was recorded at the timing of the vertical periodic signal.

For example, if the control pulse in SP mode is recorded at a timing tSP delayed from the timing of the vertical periodic signal, the control pulse will be recorded as normal X on the magnetic tape.
In order to reach the value, track pitch A (μ
m), and the field period is T o (16,7g+5e
c), the position of the control head on the take-up side with respect to the rotating drum is set in the direction up and down in the drum height direction (in other words, the X value becomes large) with respect to the normal X value If (Xo). direction), L-(tSP/2To)XAX2
If the tape speed in SP mode is VSP, then ΔX= ('jsp/2To) x (VSP
(■-/5ec)/30 frames) (all) Move to the winding side.

Regarding the SP mode, if the mechanical 2To
)XAX2 = (tEP/2To)X (A/N)X2+P holds true. Here, if the tape speed in EP mode is VEP, then VEP = (1/N) + VSP, and N = = 3.
It is.

FIG. 8 shows a block diagram of an example of a conventional circuit. The recording mode will be explained. The video signal A (FIG. 9(A)) that entered the terminal 1 is separated from the vertical periodic signal port (FIG. 9(B)) by the vertical periodic signal separation circuit 2, and is converted into crystal oscillation @18.
The oscillation circuit (counter) 3 of 30H2, which is driven by counting the clocks from , generates a signal C (FIG. 3(C)). Thresholds C+ and Cz (C1<02) are set here, and the signal H of 30H2 ((E) in the same figure) is taken out in synchronization with the vertical periodic signal opening by the threshold C1, and the SP
If it is in the mode, the signal is supplied to the waveform shaping circuit 4 via the switch SW+ and converted into a signal ((F) in the figure), and is supplied to the control head 6 via the recording amplifier 5 to be recorded on the magnetic tape. Ru.

On the other hand, in the EP mode, the output signal of the oscillation circuit 3 (
The same figure (E)) shows the time tF:p' (
The signal is delayed by 29 mesc) and converted into a signal ((L) in the same figure), which is converted into a signal ((M) in the same figure) by the waveform shaping circuit 4 and recorded on a magnetic tape by the control head 6.

Here, P=5μ amount, A=58μm, N=3°To=1
If 6.7 seconds are set and tSP=0 is entered in the middle, then te p --(NA/A)T.

The negative sign of tEP is the direction in which the pulse advances, but it cannot advance, so in reality, tEP=N
tSP' = 2To (NA/A) It is equivalent to delaying To, and tEP = NtSP' = 2X16.7- (3x515
B) x 16.7 = 29 m5ec. Therefore, the delay amount of mono multi 7 is set to 2.
Set to 9ssec.

On the other hand, in the drum servo system, the threshold value C2 of the oscillation circuit 3
Trigger pulse 2 ((D) in the figure) is taken out, converted into a sample pulse by the sample pulse generation circuit 8, and supplied to the phase comparator circuit 10. Drum PG pulse force ((G) in the same figure) (SP mode) or drum PG pulse force ((N) in the same figure) (EP mode) from the drum motor 13
, are taken out, and the signal chi (same figure (
H)'') (SP mode) or signal mode (EP mode), and the signal is output using the mono multi 15 ((I) in the same figure) (SP mode).
mode) or signal output ((P) in the figure) (EP mode), and the flip-flop 16 outputs the signal ((J) in the figure).
(SP mode) or signalically (Q) in the same figure) (EP mode), and in SP mode, via the inverter 17,
In the EP mode, the trapezoidal wave signal is directly supplied to the trapezoidal wave generating circuit 9 and is used as a trapezoidal wave signal L ((K) in the same figure) (SP mode) or a trapezoidal wave signal S ((R) in the same figure) (EP mode).

In the phase comparison circuit 10, the trapezoidal wave signals and the sample pulse are phase-compared, and the phase comparison error signal is passed through a low-pass filter (LPF) and a motor drive amplifier (MDA) 12.
is supplied to the drum motor 13 via the drum motor 1
Drive control of 3.

On the other hand, in the capstan servo system, the crystal oscillator 18
The clock is converted into a trapezoidal wave signal by a capstan reference oscillation circuit 19 and a trapezoidal wave generation circuit 21, and is supplied to a phase comparator circuit 22. The capstan FG pulse from the capstan motor 25 is converted into a sample pulse via an amplifier 26, a frequency dividing circuit 27, and a sample pulse generating circuit 28.

The phase comparison circuit 22 compares the phases of the trapezoidal wave signal and the sample pulse, and the phase comparison error signal is supplied to the capstan motor 25 via a low-pass filter (LPF) 23 and a motor drive amplifier (MDA) 24. The stun motor 25 is driven 11wJ.

On the other hand, in the playback mode, the signal from the oscillation circuit 3 or the signal from the monomulti 7 is output to the tracking monomulti 2.
A capstan reference signal is obtained at step 9, and a trapezoidal wave signal made from this signal is compared in phase with a sample pulse made from a signal obtained from the reproduction control pulse from the control head 6 via the amplifier 30, The capstan motor 25 is driven and controlled using the phase comparison i difference signal thus obtained. Note that the tracking monomultiply 29 can adjust tracking deviation, and the capstan reference signal can have a tracking variable range.

Problems to be Solved by the Invention In the above conventional circuit, the delay time of the delay circuit 7 is 291 seconds.
This is relatively large, and as a result, it is susceptible to variations in temperature characteristics, etc., and this adjustment requires a volume. Furthermore, there is a problem in that switching between EP mode and SP mode is required.

SUMMARY OF THE INVENTION An object of the present invention is to provide a control pulse recording circuit for a magnetic recording/reproducing device that reduces the delay time of a delay circuit, is less susceptible to variations in temperature characteristics, etc., and does not require switching between modes. do.

Means for Solving the Problems In FIG. 1, a vertical periodic signal separation circuit 2, an oscillation circuit 3, a switch SW2 . The waveform shaping circuit 4 and control head 6 record control pulses in different magnetic tape speed modes according to the timing of the vertical periodic signal, tsP (40
) = (tEP/N) + (P/A) ×T0, tE
P=NtSP=Ntsp-(MPT.

/A) This is an example of means for performing the processing at delayed timing.

In the action SP mode, tSP is determined by the timing of the vertical periodic signal.
(≠0)= (tEP/N)+ (P/A)×T0
Record control pulses with delayed timing.

Embodiment FIG. 1 shows a block system diagram of the first and second embodiments of the circuit of the present invention. In the figure, the same components as in FIG. 8 are designated by the same numbers, and the same signals are designated by the same numbers. Reference numerals will be given to each of them and their explanation will be omitted. In the SP mode, the output signal ho (FIG. 2(E)) of the oscillation circuit 3 is delayed by a time tSP (1,4-sec) by the monomulti 31 and becomes the signal f (FIG. 2(E)).
)), and the waveform shaping circuit 4 generates a control pulse g.
((G) in the same figure).

On the other hand, in the EP mode, the signal H is supplied as is to the waveform shaping circuit 4, and the control pulse h ((H) in the figure
).

In this way, in the first embodiment, the mechanical : When p-0 is inserted, ts p = (P/A)XT.

= (5158)X16.7 = 1.41SeC It is electrically corrected using the amount of delay.

As a result, the amount of delay is smaller than that of conventional circuits, there is almost no problem even if the amount of delay varies depending on temperature characteristics, and there is no need for an adjustment volume.

Incidentally, the height of the video head changes mechanically due to temperature changes, and as a result, the X value shifts in response to temperature changes.

Then, a system can be considered in which a temperature sensor is provided in the monomulti 31 and its time constant is varied to correct the X value. At this time, the tape speed in SP mode is three times that of EP mode, so the electrically corrected product in SP mode is
It may be 1/3 of that of P mode.

, Therefore, considering correction from low temperature to high temperature, in EP mode, the delay amount of monomulti 31 is set to 2T input cycle at room temperature.
172 T of o. It is convenient to design the Therefore, from equation (1) above, tSP= (tEP/N)+ (
P/A) XT.

■ From this, we set the EP mode to t2 p = To = 1
If it is set to 6 or 7 m5ec, the design value can be obtained as t3p=7n+sec. Of course, at this time too, the X value is SP mode.
This is the value when using standard tape.

In this way, in the case of tsP40, tEP = NtSP = N ts p - (NPTo /
From A), tSP in SP mode and EP mode.

tEP can be set arbitrarily.

In the second embodiment of the circuit of the present invention, the delay time of the monomulti 31 is set to 1 a+sec, and the signal i(
2(I)) is taken out, and the switch SW2 is connected to the terminal SP side in both the SP mode and the EP mode, and the control pulse j (FIG. 2(J)) is output. mono multi 3
The delay time of 1 is expressed by the equation (1) above. In this case, as in the first embodiment, the mechanical X value is not set to a normal value in either the SP mode or the EP mode, but the deviation in the X value is electrically corrected using the delay ω. As a result, the amount of delay varies depending on the temperature characteristics (ζ), there is almost no problem, there is no need for an adjustment volume, and
There is no need for a switch to switch between SP mode and EP mode.

FIG. 3 shows a block system diagram of a third embodiment of the circuit of the present invention, in which the same components as in FIGS. 1 and 8 are designated by the same numbers, and the same signals are designated by the same symbols. Therefore, the explanation will be omitted. The oscillation circuit 3' counts the output pulses of the crystal oscillator 18 and outputs a 30Hz signal k (Fig. 2 (K)), and has threshold values CI to C4 (C4<CI<03<0).
2) is set, the threshold C3 coincides with the rising timing t1 of the signal j (FIG. 2 (J)) in the second embodiment, and the period of the thresholds C1 to C4 is set equal to the H level period of the signal j. has been done.

The flip-flop 41 is set at the threshold C3 and reset at the threshold C4, and the control pulse t<
Figure (b)) is output. Similarly to the second embodiment, control pulses are used in both the SP mode and the EP mode.

FIG. 4 shows a block system diagram of a fourth embodiment of the circuit of the present invention, in which the same components as in FIGS. 1, 3, and 8 are designated by the same numbers, and the same signals are designated by the same numbers. The same reference numerals are used to omit the explanation. The recording mode will be explained. The vertical periodic signal port (Figure 2 (B)) is a 60Hz oscillation circuit (
signal C at the counter). The oscillation circuit 33 has a threshold value Cs.

Cs and Cy (Cs < Cs < 07) are set, and the flip-flops 34 to 30 are set according to the threshold C5.
A signal m of Hz is taken out, while a threshold value C7
A signal n of z is taken.

In the SP mode, the signal m and the signal n are ANDed at the AND gate 35 to become a signal 0 of 3αH2, which is extended by 1.411313 CI at the monomulti 33 and then generated by the control pulse generation circuit 39 as a recording control pulse. p
(same as in FIG. 2(G)). In the EP mode, the output signal m of the flip-flop 34 is transferred to the inverter 38.
The signal whose polarity has been inverted and the signal n are connected to the AND gate 35
The signal q is obtained by ANDing at
H).

On the other hand, in the drum servo system, the threshold value C of the oscillation circuit 33
A trigger pulse S is taken out by 6 and supplied to a flip-flop 40. Output signal m of flip-flop 34
is converted into a reset pulse U by the reset pulse generation circuit 37 and supplied to the flip-flop 40, and a signal V is taken out from the flip-flop 40, which is converted into the sample pulse W by the sample pulse generation circuit 17.

The drum PG pulse X from the drum motor 13 is converted into signals y and z by a monomulti 14 and 15, a signal W by a flip-flop 16, and a trapezoidal wave signal by a trapezoidal wave generating circuit 9. The drum motor 13 is driven and controlled by the output of the phase comparison circuit 10.

In the fifth embodiment of the circuit of the present invention, the delay time of the monomulti 31 is set to 1 m5ec, the switch SW2 is connected to the terminal SP side in both the SP mode and the EP mode, and the control pulse j (Fig. 2 (J) ).

This corresponds to the second embodiment.

Effects of the Invention According to the circuit of the present invention, the delay time of the delay circuit can be set smaller than that of the conventional circuit, which makes it less susceptible to variations in temperature characteristics, etc.
It has the advantage that it does not require switching between modes, and the circuit can be simplified.

[Brief explanation of drawings]

FIG. 1 is a block system diagram of the first and second embodiments of the circuit of the present invention, FIG. 2 is a signal waveform diagram of the first to third embodiments, and FIG.
4 and 4 are block system diagrams of the third and fourth embodiments of the circuit of the present invention, respectively. FIGS. 8 and 9, which show the relationship between patterns and control heads, are a block system diagram and a signal waveform diagram of an example of a conventional circuit, respectively. 1 Video signal input terminal, 2... Vertical synchronization signal separation circuit, 3.3', 33... Oscillation circuit, 4... Waveform shaping circuit, 6... Control head, 31... Mono multi , 34.41... flip-flop, 35...
AND gate, 38... Inverter, SW 2...
·switch. Patent applicant: Japan Victor Co., Ltd. Procedural amendment August 9, 1985 1985 Patent application No. 121168 26 Title of invention Control pulse recording circuit 3 for magnetic recording and reproducing device, relationship with the amended person case Patent application Address: 3-12 Moriyamachi, Kanayō-ku, Yokohama-shi, Kanagawa Prefecture 221 Name (432) Japan Victor Co., Ltd. Representative Director and President Kunio Kakiki 4 Agent Address: 5-7-6 Kojimachi, Chiyoda-ku, Tokyo 102
, Detailed description of the invention and brief description of the drawings in the specification to be amended. 7. Contents of amendment (1) “mescJ” written in line 13 on page 10 in the specification
is corrected to l''m5ecJ. ■ "Mote" written in lines 17 to 18 of page 11 is corrected to "mode". ■ Delete "ne" written on page 12, line 20. (A) "Signal W" written on page 20, line 18 of the same document is corrected to "signal Z". ■ Same, page 22, line 5, [1 video] is [1...
・Correct with Video J.

Claims (3)

[Claims] (1) Magnetic recording and playback that has two pairs of video heads with gaps of different azimuth angles and records and reproduces video signals by switching the two sets of video heads according to different magnetic tape speeds. In the control pulse recording circuit of the apparatus, the track pitch of the video head for the faster magnetic tape speed V_S_P among the above different magnetic tape speeds is set to A, and the track pitch of the video head for the lower magnetic tape speed V_E to be set as A.
A/N the track pitch of the video head for _P,
The ratio of the magnetic tape speeds is 1/N, and the difference between the relative height C_1 of the video head for the above-mentioned fast magnetic tape speed and the video head for the above-mentioned slow magnetic tape speed and the ideal relative height C_0 at the normal X value is P(>0)=(C_
0-C), and if the field period is T_0, then control pulse recording in the different magnetic tape speed modes is t_S_P(≠0
)=(t_E_P/N)+(P/A)×T_0, at the above slow magnetic tape speed, t_E_P=Nt_S_P−(N
PT_0/A) (t_S_P≠0) are configured to be performed at delayed timings, respectively, and the X value deviation adjustment due to the control head position adjustment in the above-mentioned fast magnetic tape speed mode is corrected by the delay amount t_S_P. A control pulse recording circuit for a magnetic recording/reproducing device characterized by being equivalent. (2) Magnetic recording and playback that has two pairs of video heads with gaps of different azimuth angles and records and reproduces video signals by switching the two sets of video heads according to different magnetic tape speeds. In the control pulse recording circuit of the apparatus, the track pitch of the video head for the faster magnetic tape speed V_S_P among the above different magnetic tape speeds is set to A, and the track pitch of the video head for the lower magnetic tape speed V_E to be set as A.
A/N the track pitch of the video head for _P,
The ratio of the magnetic tape speeds is 1/N, and the difference between the relative height C_1 of the video head for the above-mentioned fast magnetic tape speed and the video head for the above-mentioned slow magnetic tape speed and the ideal relative height C_0 at the normal X value is P(>0)=(C_
0-C), when the field period is T_0, control pulse recording in the slow magnetic tape speed mode is performed at the timing of the vertical synchronization signal separated from the video signal, and control pulse recording in the fast magnetic tape speed mode is performed. From the timing of the vertical periodic signal, t
_S_P=(P/A)×T_0 It is configured to be performed at a delayed timing, and the adjustment of the X value deviation by adjusting the position of the control head in the above-mentioned fast magnetic tape speed mode is equivalent to correction by the delay amount t_S_P. A control pulse recording circuit for a magnetic recording/reproducing device, characterized in that: (3) Magnetic recording and playback that has two pairs of video heads with gaps of different azimuth angles and records and reproduces video signals by switching the two sets of video heads according to different magnetic tape speeds. In the control pulse recording circuit of the apparatus, the track pitch of the video head for the faster magnetic tape speed V_S_P among the above different magnetic tape speeds is set to A, and the track pitch of the video head for the lower magnetic tape speed V_E to be set as A.
A/N the track pitch of the video head for _P,
The ratio of the magnetic tape speeds is 1/N, and the difference between the relative height C_1 of the video head for the above-mentioned fast magnetic tape speed and the video head for the above-mentioned slow magnetic tape speed and the ideal relative height C_0 at the normal X value is P(>0)=(C_
0-C), and the field period is T_0, the control pulse recording in both of the different magnetic tape speed modes is determined by the timing of the vertical period signal separated from the video signal, t_S_P=t_E_P={1-(1/
N)}×(P/A)×T_0 It is configured to be performed at a delayed timing, and the X value deviation adjustment due to the control head position adjustment in the above-mentioned fast magnetic tape speed mode is corrected by the delay amount t_S_P. A control pulse recording circuit for a magnetic recording/reproducing device characterized by being equivalent.