JPS61229256A - Recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain excellent ATF tracking characteristics with a common recording/reproducing head by providing a couple of recording/reproducing heads in common use of the 1st and 2nd speeds and plural flying erase heads. CONSTITUTION:Recording/reproducing heads 30A, 30B in common use of the SP and LP modes are mounted on a rotary drum 31 at a nearly 180 deg. angle interval toward the rotating direction K1 of the drum, and flying erase heads 32A, 32B are provided while keeping a nearly 90 deg. angle interval between the recording and reproducing heads. After a video signal or the like recorded on two tracks is erased by scanning the flying erase heads 32A, 32B over two adjacent tracks for a tape 33 running in the direction of the arrow K2 along the peripheral face of the drum 31, the recording/reproduction head 30A scans the 1st track in the said two tracks and the recording/reproduction head 30B scans the 2nd track successively and the recording/reproducing heads 30A, 30B record respectively the video signal.

Description

[Detailed description of the invention] The present invention will be explained in the following order.

A. Field of industrial application B. Overview of the invention C. Prior art D. Problem to be solved by the invention E. Means for solving the problem F. Effect G. Embodiment G1 Head arrangement W (Fig. 1) 02 Circuit configuration and operation (Figs. 2 to 4) H Effect of the invention A Field of industrial application This invention relates to a recording/reproducing device, and in particular, the present invention relates to a recording/reproducing device in which a frequency is recorded on recording tracks formed in sequence across the running direction on a recording medium. An automatic track tracking method that records different pilot signals cyclically together with the video signal, and then tracks the playback head to a predetermined trunk by detecting the frequency component of the pilot signal played from an adjacent track during playback. (hereinafter referred to as the ATF method) tracking control device is applicable and suitable.

B. Summary of the Invention The present invention provides a recording and reproducing apparatus capable of switching the tape running speed between a first speed and a second speed, in which a plurality of flying erase heads superimpose an erase signal on the tape in the first speed mode during recording. By recording a plurality of pilot signals with different frequencies, it is possible to obtain good tracking characteristics in any speed mode.

C. Prior Art As shown in FIG. 5, a four-frequency type tracking control device has been proposed in which pilot signals of four frequencies are sequentially recorded on a recording track as an ATF type tracking control device.

That is, this tracking control device uses a pilot signal detection circuit (1) having a low-pass filter configuration to send a part of the signal S1 of the playback output of a rotating video head as a recording/playback head.
In response to this, a reproduced pilot signal S2 whose component is the reproduced output of the pilot signal recorded on the magnetic tape as a recording medium is generated, and this reproduced pilot signal S2 is supplied to an error signal forming circuit (3). Error signal formation circuit (3
) sends out a tracking error signal S3 formed under the control of the reference signal generating circuit (4).

On the tape (5), as shown in FIG. 6, a plurality of, for example, four types of pilot signals f1. f2+
Four video tracks TI, T2 .fa, r4 are recorded. T3. The sets of T4 are formed diagonally and closely together so as to repeat in a cyclical manner. Here, select the recording/playback head (
The effective width of the video head constituting the video head 6) is selected to be approximately equal to the width of the tracks T1 to T4, for example, and as shown by the solid line in FIG. If the track (this is called a playback track) is correctly tracked, the pilot frequency component included in the playback output will be 1lI11 by playing back only the pilot signal recorded on the track.
On the other hand, when the recording/reproducing head (6) is shifted to the right or to the left with respect to the track as shown by the broken line, recording is performed on the track adjacent to the right or left side of the playback track. By also reproducing the pilot signal, there are two types of pilot frequency components included in the reproduced output, and the magnitude of each pilot frequency component is equivalent to the opposing length of the recording/reproducing head facing the corresponding track. It is made to become.

However, the frequencies f1 to f4 of the four types of pilot signals are selected in the lower band of the color component converted to a low frequency (600 to 700 (kllz)), and the circulating 4
For example, in the tracks T1 to T4, centering on the odd-numbered tracks TI and T3, the frequency difference with the pilot signal of the right track is Δf^, and the frequency difference with the pilot signal of the left track is ΔfB. and the even-numbered track T2. Centering on T4, the frequency difference with the pilot signal of the right track is ΔfB, and the frequency difference with the pilot signal of the left track is Δf^.

Therefore, the head (6) is on odd-numbered track T1. When reproducing T3, if there is a signal component with a frequency difference Δf^ as a frequency component of the pilot signal included in the reproduced signal, it can be seen that the head (6) is in a right-shifted state, and also if the frequency difference is Δf, If there is a signal component of , it can be seen that the head (6) is in a left-shifted state, and further, if there is no signal component with a frequency difference of ΔfA and Δf, it can be seen that the head (6) is correctly tracked.

Similarly, the head (6) moves to the even numbered track T2゜T.
4, if there is a signal component with a frequency difference of Δfn as a frequency component of the pilot signal included in the reproduced signal, it is known that the head (6) is shifted to the right, and also if the frequency difference is Δf^. If there is a signal component, it can be seen that the head (6) is shifted to the left.

Here, the first, second, third, and fourth tracks T1. T
2. T3. Frequency fv, f2 assigned to T4
．． (3, f+ is fz = 102 (kHz).

f2=116(kllz), f3=16
0 (kllz), f+= 146 (kHz), so the difference frequencies Δf^ and Δf are: Δf^=lft ft 1=lfi f41=
14 (kHz) --(1) ΔfB=lf2-f31=lf4-ft I=44
(kHz) --(2) is selected.

A reproduced signal S1 having such content obtained from the head (6) is given to a pilot signal detection circuit (11) having a low-pass filter configuration, and is multiplied by a reproduced pilot signal S2 obtained by extracting a pilot signal included in the reproduced signal St. The reference pilot signal Sll of the reference signal generation circuit (4) is applied to the multiplication circuit (14) as a first multiplication input.

The reference signal generation circuit (4) includes a pilot signal generation circuit (16) that generates four types of pilot frequency outputs of frequencies f1 to f4, and a tape recording/reproducing head of a pair of recording/reproducing heads in association with a rotating drum (not shown). The head switching signal RF-S changes the logic level every time the head scanning the head switches.
W (FIG. 7A). In this ~, the switch circuit (17) has a quaternary counter circuit that performs a counting operation every time the level of the head switching signal RF-SW changes. ˜T4 can be sequentially repeated, and this track Tl
-74 gate signals open the gates respectively °ζ
As shown in Figure 7B, the pilot signal generation circuit (16)
The pilot frequency f! - f4 are sequentially sent out as reference pilot signals Sll.

Note that the reference pilot signal Sll obtained at the output end of this switch circuit (17) is sent to the recording/reproducing head (6) as a recording pilot signal S4 via a signal line (18) during recording.
Thus, while the head (6) scans the first to fourth tracks T1 to T4, the corresponding frequency f1
-f4 pilot signals are sequentially applied to the head (6) to record on each track T1-T4.

In this way, while the head (6) scans the first to fourth t1 tracks T1 to T4, the part -
By multiplying the reproduced pilot signal S2 obtained at the output end of the pilot signal detection circuit (11) by the reference pilot signal S11 generated in synchronization with the reproduced track, the frequency included in the reproduced pilot signal S2 is detected when there is a tracking error. A multiplication output 312 is obtained that includes a difference signal component having a frequency that is the difference between the frequency of the reference pilot signal Sll and the frequency of the reference pilot signal Sll (actually, the multiplication output S12 also includes other signal components such as the sum frequency component). This multiplication output S12 is outputted to first and second difference frequency detection circuits (20) and (21), each of which is composed of a bandpass filter.
) is given to

The first difference frequency detection circuit (20) extracts the signal component of the difference frequency Δf^ based on the above-mentioned equation (1) in the multiplication output S12, and extracts this signal component and converts it into a direct current circuit (20) having a peak detection circuit configuration. 22), the signal is converted to DC to obtain the first error detection signal S13 at DC level. Similarly, the second difference frequency detection circuit (21) applies the above-mentioned (2) to the multiplication output S12.
When a signal component having a difference frequency Δf based on the equation is included, this is extracted to obtain a second error detection signal 314 from the DC conversion circuit (23).

Here, the head (6) moves to the first, second, third, fourth track TI, T2 . T3. When trying to track T4 (therefore, the switch circuit (F) changes the frequency to fz at the timing corresponding to each track Tl, T2, T3, and T4 as shown in FIG. 7B.

Reference pilot signal Sll of f2+ f3+ f4
If the reproduction pilot signal S2 is shifted to the right, the reproduction pilot signal S2 obtained based on the reproduction signal Sl of the head (6)
As shown in FIG. 7Ct, the frequencies f1 and f2+f2 and fl, fl and f4. The pilot signals of f+ and fl are included, and the multiplication output S12 is shown in FIG. 7D.
As shown in I, the difference frequency Δf^ (=f1~f2)
, Δfa (=f2-f3).

Δ"^ (=f3~f4), Δfs (=f4~ft
) in sequence. On the other hand, the head (6
) is shifted to the left, the regenerated pilot signal s2 becomes the seventh
As shown in FIG. 02, the frequencies f4 and fl are sequentially applied.

fl and f2. f2 and f3+ fl and f4 pilot signals are included, and the multiplication output S
12 is the difference frequency Δtn (=
f+~f+), Δf^ (=f1~f2).

It sequentially includes signal components Δfs (=f2 to f3) and Δf^ (=f3 to f4).

Thus, as shown in FIG. 7 E and F (for example, indicating a right-shifted state), the first and second error detection signals whose DC level rises from 0 every time the head (6) switches the scanned track. S13 and S14 can be obtained from the DC conversion circuits (22) and (23).

The first and second error detection signals S13 and S14 are supplied to the subtraction circuit (24) as an addition input and a subtraction input, respectively, so that the first and second error detection signals
Every time the error detection signals 313 and S14 are obtained alternately, a subtraction output S15 that changes in an alternating current manner is obtained. This subtraction output S15 is the first one of the direct changeover switch circuit (25).
The signal is applied to the input terminal a1, the polarity of which is inverted in the inverting circuit (26), and the polarity is applied to the second input terminal a2.

The changeover switch circuit (25) receives the head changeover signal RF-8-
For example, if the head (6) is on an odd track TI
, T3, the switching operation is performed to the first input terminal al side while scanning the even-numbered tracks T2 . When scanning T4, a switching operation is performed to the second input terminal a2, and thus when the head (6) is shifted to the right as shown in FIG. A level output 316 is obtained (on the other hand, when there is a right shift state, the DC level output 316 has a magnitude corresponding to the left shift amount and becomes negative polarity), and this is an output amplification circuit (27) consisting of a DC amplifier. The tracking error signal S3 is sent out as a tracking error signal S3.

Incidentally, if the head (6) is shifted to the right, for example, when the reproduced track is an odd numbered track TI, T3, a signal component of the difference frequency Δr^ appears at the output terminal of the multiplication circuit (14), so that the first difference frequency is The output from the detection circuit (20) side is given to the subtraction circuit (24), and since the changeover switch circuit (25) is switched to the first input terminal AL side at this time, a tracking error signal of a positive DC level is generated. Send S3. On the other hand, the playback track is the even numbered track T2. T
4, the output terminal of the hook circuit (14) has a difference frequency Δf,
When the signal component appears, the output from the second difference frequency detection circuit (21) is given to the subtraction circuit (24),
Moreover, at this time, the changeover switch circuit (25) is switched to the second input terminal a2 side, so the polarity of the negative output of the subtraction circuit (24) is inverted by the inverting circuit (26) to track the positive DC level. It is sent as an error signal S3.

Therefore, if this tracking error signal S3 is used as a correction signal in the phase servo circuit of the capstan servo loop and the tape running speed is corrected so that it slows down when it is positive and speeds up when it is negative, it is possible to correct the tape running speed between the video head and the playback track. The phase shift can be corrected, thus realizing correct ATF tracking servo.

D Problems to be Solved by the Invention By the way, using the ATF tracking control device with the above configuration, there is a normal recording mode (this is called SP mode) in which a video signal is recorded while running the tape at a standard speed, and this SP mode. A recording/playback device (VTR) is designed to record and play back in two recording modes: a long-time recording mode (this is called LP mode) that records video signals at half the tape speed of the tape mode. It is being

In order to record video signals on a tape at different tape speeds, the relationships between the tracks formed by recording in a slow tape speed mode, that is, the LP mode, are as shown in FIG. It is necessary to form the recording tracks so that they are connected to each other without at least a guard band intervening. However, when recording is performed in SP mode, which has a head rotation speed that satisfies these conditions and has approximately twice the tape speed, as shown in FIG. 9, there is a considerable gap between tracks formed on the tape. A wide girt band will be formed.

If there is a wide gart band G as in the case of recording in the SP mode in Figure 9, when the recording/playback head just tracks each trunk during playback, the gart band G
There is a problem in that the crosstalk component based on the pilot signal arriving from the adjacent track beyond 200 nm becomes extremely small, making it impossible to obtain information on the difference signals Δf^ and ΔfB.

To solve this problem, a recording/reproducing head with a head width that can obtain crosstalk between pilot signals recorded on adjacent tracks when the playback mode is selected as LP mode or SP mode is required. Prepare a recording head corresponding to each mode, select the recording/reproducing head corresponding to the selected playback mode according to the playback mode selection, and obtain a playback pilot signal for use in rough king control (ATF). It is considered good.

However, with this method, there is a problem in that the number of recording/reproducing heads must be prepared in accordance with the reproduction mode.

For example, as mentioned above, V with LP mode and SP mode
In the case of TR, normally two heads must be prepared for each mode, so a total of four recording/reproducing heads must be provided. In practice, it is necessary to provide at least one flying erase head in addition to this. If such a large number of recording/reproducing heads are mounted on the rotating drum, the structure on the rotating drum becomes complicated and large, so it is desirable to reduce the number of heads mounted on the rotating drum as much as possible.

The present invention has been made in view of the above, and provides a recording and reproducing device that can obtain good ATF tracking characteristics using a common recording and reproducing head without providing a recording and reproducing head for each mode. be.

E Means for Solving the Problems The recording/reproducing apparatus according to the present invention adjusts the tape running speed to the first speed.
A recording/reproducing device that switches between a first speed and a second speed includes a pair of recording/playback heads that can be used for both the first and second speeds and a plurality of flying erase heads, and when recording, the recording/reproducing device switches between a first speed mode and a second speed mode. Here, the plurality of flying erase heads are configured to record a plurality of pilot signals having different frequencies while being superimposed on the erase signal.

F Function A plurality of, for example, two flying erase heads are provided in addition to the recording and reproducing heads for the first and second speeds, that is, for both the SP mode and the LP mode, and during recording, in the SP mode, the two flying erase heads are used to erase. A plurality of pilot signals having different frequencies are recorded superimposed on the signal, thereby obtaining good tracking characteristics that are not affected by the guard band even in SP mode.

G Embodiment F2 An embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4.

Arrangement of G1 heads FIG. 1 shows the arrangement of each head according to the present invention.
Recording/playback head (30A) for both SP mode and LP mode
and (30B) are mounted on the rotating drum (31) with an angular spacing of approximately 180° with respect to the rotational direction Kl of the drum. Flying erase heads (32A) and (32B) are arranged with an angular spacing of °.Furthermore, the flying erase heads (32^) and (32B) are connected to the recording/reproducing heads (30^) and (30B). Considering the phase difference of 90° and using the recording/reproducing heads (30^) and (30B) as a reference, there is a predetermined level difference between them, that is, in this case, Tp/2 (
Tp is the track pitch).

In this way, the flying erase heads (32^) and (32r3) scan across two adjacent tracks on the tape (33) running in the direction of arrow 2 along the outer circumferential direction of the drum (31). After the video signals recorded on the two tracks are erased, the first track of the two tracks is moved to the recording/playback head (3
The recording/reproducing head (30B) performs an accompanying scan on the second track, and then the recording/reproducing head (30B) performs an accompanying scan on the second track.
30^) and (30B), video signals and the like are recorded respectively.

Now, at this stage of the recording operation, in the present invention, the second speed where no guard band exists, that is, LP
In this mode, multiple pilot signals with different frequencies are recorded in the recording/reproducing heads (30A) and (30B) that record video signals etc. as before, but the first pilot signal with a guard band
In the SP mode, the flying erase heads (328) and (32B) record a plurality of pilot signals with different frequencies.

02 Circuit configuration and operation Figure 2 shows the circuit configuration.
34) is an input terminal to which a video signal or an audio FM (AF flaw signal) is supplied, and the signal from this input terminal (34) is supplied to one input side of an adder (35).
36) is a pilot signal generation circuit that generates a plurality of pilot signals of different frequencies for ATF, and the pilot signals from this pilot signal generation circuit (36) are added together via the contact a side of the switch circuit (37). Vessel (35
) is supplied to the other input terminal of the switch circuit (3
7) to one input side of the adder (38). An erase signal from an erase signal generation circuit (39) is supplied to the other input terminal of the adder (38). The switch circuit (37) is connected to the contact a side in the LP mode, and is switched to the contact a side in the SP mode. Therefore, the pilot signal is superimposed on the video signal etc. in the LP mode, and is recorded superimposed on the erase signal in the SP mode.

The output side of the adder (35) is selectively connected to the recording amplifier (41^) and (41B) via the switch circuit (40).
The output sides of recording amplifiers (41^) and (41B) are connected to recording/reproducing heads (30A) and (30B), respectively. Further, the output side of the addition 1B (38) is connected to the flying erase head (32) via a switch circuit (42).
A) and (32B).

The switch circuit (40) is controlled by the switching pulse 5WP1 as shown in FIG. 3A. For example, when the switching pulse 5WP1 is at a high level, the switch circuit (40) is connected to the contact a side,
When t is at a low level, it is switched to the contact side. Also,
The switch circuit (42) is controlled by a switching pulse 5WP2 which is advanced by 90° from the switching pulse 5WPx as shown in FIG. 3B.
42) is switched to the contact a side when the switching pulse 5WP2 is at a high level, and is switched to the contact a side when the switching pulse 5WP2 is at a low level.

Now, in the LP mode, the switch female circuit (37) is connected to the contact a side, and the pilot signal generation circuit (36)
The pilot signal from the input terminal (34) is supplied to the adder (35) and added to the video signal etc. from the input terminal (34). When the switching pulse 5WPx is at a high level, the pilot signal added to the video signal, etc. is supplied to the recording amplifier (41A) through the contact a side of the switch circuit (40), and is amplified by the recording/reproducing head ( 30^) on the tape (33) (Fig. 1). When the switching pulse 5WPt is at a low level, it is supplied to the recording amplifier (41B) through the contact side of the switch circuit (40) and is amplified and recorded on the tape (33) by the recording/reproducing head (30B). Ru.

In the SP mode, the switch circuit (37) is switched to the contact side, the pilot signal from the pilot signal generation circuit (36) is supplied to the adder (38), and the erase signal from the erase signal generation circuit (39) is supplied to the adder (38). is added to the signal. The pilot signal added to this erase signal is supplied to the flying erase head (32A) through the contact a side of the switch circuit (42) when the switching pulse 5WP2 is at a high level.
33). In addition, switching pulse 5WP
When signal 2 is at a low level, the signal is supplied to the flying erase head (32B) through the contact side of the switch circuit (42), thereby recording on the tape (33).

Of course, when in SP mode, video signals etc. are sent to the recording/playback head (3).
0^) and (30B), and when in LP mode, the erase signal is sent to the flying erase head (32A).
) and (32B).

Flying erase head (328) and (3
The track width of 2B) is determined as follows.

In other words, if the track pitch of the recording/reproducing heads (30^) and (30B) in SP mode is TP and the track width is T%1, then Tp + (Tp-Tw) = 2Tp
It is determined by Tw. As a result, in the sp mode, although a guard band is formed as described above on tracks such as video signals recorded by the recording/reproducing heads (30^) and (30B), the flying erase heads (32A) and (32B) Guard bands will no longer be formed on the pilot signal tracks recorded in .

Figure 4 shows this state, with the solid line indicating the recording/reproducing head (
30^) and (30B), and the broken line represents the track pattern of the video signal etc. recorded with the flying head (32^) and (30B).
It shows the track pattern of the pilot signal recorded in A) and (32B).

In this way, in the SP mode, the flying erase heads (32^) and (32B) having a predetermined head width are
A track pattern without guard bands can be formed by recording a pilot signal using . Furthermore, when recording a pilot signal with a recording/playback head, there is an upper limit to the pilot signal recording current due to the so-called spurious problem, but when recording a pilot signal with a flying erase head, this problem is freed. Therefore, sufficient recording can be made and the output of pilot signal crosstalk during playback can also be improved.

Effects of the Invention H As described above, according to this invention, the SP/
When a pilot signal is recorded with a head that can also be used in LP mode, a guard band is formed, which deteriorates the tracking characteristics of the ATF. However, in this invention, a plurality of flying erase heads with a predetermined trunk width are provided, and this allows the pilot signal to be used as an erase signal. Since the area in which the pilot signal is recorded is substantially increased, recording can be performed with sufficient recording current, and S
Good tracking characteristics can also be obtained in P mode.

[Brief explanation of drawings]

FIG. 1 is a neo route diagram showing the arrangement of the head according to the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, FIG. 3 is a signal waveform diagram for explaining the operation of FIG. 2, and FIG. The figure is a route map showing a track pattern for explaining the present invention, Figure 5 is a block diagram showing the principle configuration of the ATF luffing control device, Figure 6 is a route map showing the track pattern, and Figure 7 is a route map showing the track pattern. FIG. 5 is a signal waveform diagram showing important signals, and FIGS. 8 and 9 are route charts showing changes in track patterns when the recording mode is switched. (30^), (30B) are recording/reproducing heads, (32^). (32B) is a flying erase head, (35). (38) is an adder, (36) is a pilot signal generation circuit, (37), (40), (42) are switch circuits, and (39) is an erase signal generation circuit. Fig. 7 To-, 7/z7- Fig. 8 Shiraffe L Scene 1 Fig. 8

Claims (1)

[Claims] A recording and reproducing device capable of switching a tape running speed between a first speed and a second speed, comprising: a pair of recording and reproducing heads that can be used for both the first and second speeds; and a plurality of flying erase heads. A recording/reproducing apparatus comprising: a plurality of pilot signals having different frequencies which are superimposed on an erase signal by the plurality of flying erase heads in a first speed mode during recording.