JPS62121951A - Reproducing device - Google Patents

Abstract

PURPOSE:To make specific information such as program searching information readable by controlling the number of rotation of a drum and a tape speed so that at the time of fast tape forwarding the relative speed between a tape and a head can be constant and larger than that at the time of normal reproduction. CONSTITUTION:A reel servo circuit 26 travels the tape 15 at a constant speed of m.N.Vt in a (m.N)-fold fast forwarding mode under the control of a microcomputer 30. A drum servo circuit 29 rotates and controls rotating heads 11A and 11B at a constant speed of m.VD'. Here the Vt and VD' show a tape speed at the time of normal reproduction and N-fold drum (head) speed at the time of fast forwarding, respectively. As a result, the absolute value of the magnitude (thetaT-thetaR) of an angle made thetaT at the time of (m.N)-fold speed can be below some critical value, whereby a relative speed of m.VR' higher by m-times than a relative speed VR' at the time of N-fold speed (namely, a relative speed VRO at the time of normal reproduction) can be obtained. Thus program searching information can be read out at the time of feeding a tape at a high speed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a playback device suitable for use in reading specific information when feeding a recording medium at high speed, particularly in a rotary head type playback device. .

[Summary of the invention]

This invention controls the drum rotational speed or tape speed so that the relative speed between the tape and the head during high-speed tape feeding is greater than that during normal playback and is constant, and the head trajectory angle θT and the track angle θR on the tape are adjusted. Size of the angle 1
θD - θR | By preventing the value from exceeding a certain limit value, the number of blocks that can be read out consecutively is at least l blocks or less, so that specific information such as cue information can be read out. It is.

[Conventional technology]

In conventional rotary head type recording and reproducing devices, a fixed head other than the rotary head is provided to read specific information such as the tape feed amount and tape position during high-speed tape feeding such as fast forwarding and rewinding of the tape as a recording medium. This fixed head records, for example, a control (
This is done by reading out signals such as CTL) signals and address signals.

However, in the case of such conventional methods, it is necessary to provide a dedicated fixed head in addition to the rotary head, which increases the number of production steps such as manufacturing, processing, assembly, and adjustment, and also increases the cost. It's inconvenient.

Furthermore, there are performance problems such as the inability to obtain output from the fixed head due to tape repelling or flailing during high-speed tape feeding.

Furthermore, since specific information is recorded using a fixed head, it is necessary to secure a dedicated recording area in the longitudinal direction of the tape, which limits the area in which the original information can be recorded using the rotating head. There are also some inconveniences.

Therefore, Kunito Motoide previously proposed a method that could read specific information during high-speed tape transport by controlling the relative speed of the tape and head during high-speed tape transport to be equal to the relative speed during normal playback. I did it (Special depot 59-1
16,115).

[Problem that the invention seeks to solve]

However, in this method, each track is recorded without forming a guard band, so as can be seen from FIG. 5 and FIG. Taking F F) as an example, as the speed value increases, the number of blocks that can be read continuously on a certain track decreases. For example, in Fig. 6, if the head trajectory is a, the number of blocks that can be read in trunk A1 is approximately 3 blocks, and the head trajectory is a.
If the head trajectory with the larger double speed value is b, trunk A1
The number of blocks that can be read continuously is about 2 blocks, and when the head trajectory with a higher speed value than the head trajectory is C, about 1 block, and as the speed value increases, the number of blocks that can be read continuously decreases. Therefore, if the speed value is too fast, even if the data can be extracted, it may not fill 1 consecutive blocks and it may become meaningless. In other words, the limit speed value at which meaningful 1n information can be read is determined. Therefore, it becomes necessary to set this limit double speed value.

This invention has been made in view of the above, and provides a playback device that sets a limit double speed value at which meaningful information can be read, so that the head can reliably read specific information even when the tape is fed at a higher speed. It is something to do.

[Means for solving problems]

The playback device according to the present invention has a tape (
15) and the heads (11A) and (IIB) so that the relative speed is greater than that during normal playback and is constant, the drum rotation speed or tape speed is controlled, and the head trajectory angle θ and the track angle θR on the tape are adjusted. size of the angle 1
The structure is such that 0th block - θR| does not become larger than a certain limit value.

[Effect]

By increasing the relative speed between the tape and the head during high-speed tape feeding than during normal playback, when the double speed value increases, the head trajectory angle θ and the trunk angle on the tape (R
EC angle) The size of the angle formed by θR |θT−θR| should not be larger than a certain limit value. This allows the head to read out specific information such as cue information even if the tape is fed at a higher speed.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail based on FIGS. 1 to 4.

First, the basic principle of this invention will be explained with reference to FIGS. 3 and 4. Figure 3 shows tape speed and drum (head)
It shows the relative velocity with respect to the speed in vector form, and FIG. 3A shows the case of fast forwarding (FF), and FIG. 3B shows the case of rewinding (REW).

In each figure, Vt is the tape speed during normal playback, Vt
Do is the drum (head) speed during normal playback, VRO
is the relative speed during normal playback, N is the double speed value, ■D' is the drum (head) speed at N times speed during fast forward, V/ is the relative speed at N times speed during fast forward, V , ;/ is the speed when rewinding The drum (head) speed at N times speed, VR'' is the relative speed at N times speed during rewinding, and m is the multiple.

Now, in FIG. 3A, the relative speed at N times speed is equal to the relative speed at normal playback, that is, VR'
Select the drum (head) speed ■D' so that = VRO. At this time, the angle formed between vR' (head trajectory direction) and the tape longitudinal direction is 0 (head trajectory angle). Here,
Assuming that the speed value is further increased from N times the speed and the condition of VR'=VRO is satisfied, θ1 increases and the head trajectory becomes increasingly steep.

In FIG. 4, a represents the trajectory of the head during fast forwarding, and b represents the trajectory of the head during rewinding. When this happens, the fifth
As is clear from the figure and Fig. 6, the number of blocks that can be read consecutively decreases, and even if information can be read, it is meaningful (
For example, information that can be used for cueing may not be available.

Therefore, if 6 teeth at N times speed is the limit head trajectory angle at which meaningful information can be obtained, then the drum (head) speed should be adjusted so that the head trajectory angle becomes 6 teeth at m-N times speed (m>1). , as shown in FIG. 3A, if m・■D', then θT is equal to θT at N times the speed, that is, m−
6 guns at N times speed will never be larger than 6 guns at N times speed. Therefore, the number of blocks that can be read continuously is N-V
This means that it will never decrease from what it was at t.

In this way, in this invention, when sending the tape at a higher speed,
The size of the angle between the head trajectory angle θ t and the track angle on the tape (REC angle) is a certain limit value 1 θ d − 〇R1, that is, information that can be read continuously is meaningful (for example, information that can be used for cueing) The head trajectory angle θT gives a limit of
and the angle θR of the trunk on the tape. This allows the head to read specific information such as cue information even if the tape is fed at a higher speed.

FIG. 1 shows the circuit configuration of a first embodiment of the present invention, in which an analog signal from an input terminal (1) is supplied to an analog-to-digital converter (3) through a low-pass filter (2). Here, the analog signal is converted into a digital signal and then supplied to the recording signal generation circuit (5) via the contact a side of the switch circuit (4). Furthermore, by switching the switch circuit (4) to a contact state, it is also possible to directly supply the digital signal from the terminal (6) side to the recording signal generation circuit (5).

The recording signal generating circuit (5) performs signal processing such as adding an error correction code to the data, interleaving or modulating the data based on the timing signal from the timing generating circuit (7), and then sends the signal to the switch circuit (8). supply to.

The switch circuit (8) is a rotating head (IIA).

(IIB''), and the half-rotation period including the tape contact period of the head (IIA) and the tape contact period of the head (IIB) are determined by the switching signal from the timing generation circuit (7). This timing generation circuit (7) is switched alternately with a half-rotation period including
is a rotary head (IIA) from a pulse generator (not shown).
), (IIB) Rotary head (IIA) obtained in synchronization with the rotation of the rotational drive motor (12).

A pulse of 301 (z) indicating the rotational phase of (IIB) is supplied.The signal from the switch circuit (8) switched by the switching signal from the timing generation circuit (7) is transmitted to the amplifiers (9A) and (9B). ), the switch circuits (108) and (IOB”) are amplified, respectively.
Rotating head (IIA), (I
IB) and is recorded on a magnetic tape (15) wound on reels (13) and (14). The switch circuits (10^) and (IOB) are connected to the contact R side during recording, and are switched to the P side during playback.

In addition, (16A) and (16B'') are switch circuits during playback, and (IOA) and (IOB) are contact points P.
(IIA)
, (IIB), which are supplied with playback outputs from these amplifiers (16A), (16A), (1
6B) are supplied to a switch circuit (17). The switch circuit (17) uses the switching signal 3011z from the timing generation circuit (7) to control the half-rotation period including the tape contact period of the head (IIA) and the tape contact period of the head (11[1), similar to during recording. It is alternately switched with a half-rotation period including a period.

The output signal switched by this switch circuit (17) is supplied to an electromagnetic conversion circuit (18) including an equalizer, a comparator, and a PLL. And this electromagnetic conversion circuit (
The output signal from 18) is supplied to an error correction circuit (19), where error correction is performed as necessary. and,
further supplied to a digital-to-analog converter (20);
Here, the digital signal is converted into an analog signal and then passed through a low-pass filter (21) and taken out as the original analog signal at the output terminal (22). In addition, if you want to directly extract digital data, an error correction circuit (1
Digital data can be derived from the output side terminal (23) of 9).

Also, (2,4) and (25) are reels (13)
, (14) is a rotation detector for detecting the rotation period of these rotation detectors (24), (25).
) is supplied to the reel servo circuit (26).

The output of the reel servo circuit (26) is the reel (13),
(14) are supplied to motors (27) and (2B), respectively, and the reels (13) and (14) are rotationally driven by these motors (27) and (28).

Further, (29) is a drum servo circuit that drives and controls the motor (12), and this drum servo circuit (29) and reel servo circuit (26) are controlled by a microcomputer (30) as a system controller. is being done. As described above, the head trajectory angle θT at m-N times the speed is the same as that at the N times speed, but the relative speed is m times higher.

Therefore, at m·N times the speed, the characteristics, time constants, etc. of the electromagnetic conversion circuit (18) and error correction circuit (19) are changed under the control of the microcomputer (30) so that they operate with a clock m times faster than normal. It will be done.

Further, subcode information as specific information is supplied to the microcomputer (30) from a subcode extraction circuit (31) provided on the output side of the error correction circuit (19), and thereby the program The so-called cue number, time code, etc. is performed. Note that during normal playback, the tape is driven by a capstan.

Now, in comparison with FIG.
) is run at a constant speed of m-N-Vt, and the rotating head (118), (IIB) is driven by the drum servo circuit (29).
is driven in constant rotation at a speed of m-Vp', and as a result m
- The head trajectory angle θT at N times the speed is equal to the head trajectory angle θ at the N times speed, and the size of the angle between this head trajectory angle θ and the angle of the track on the tape (R2O angle) θR] θd − θR | is not larger than the angle between the head trajectory angle θd and the track angle θR on the tape, which gives a certain limit value, i.e. the limit at which information that can be continuously read is meaningful. m- which is m times faster than the relative speed VR' (that is, the relative speed VRO during normal playback)
The relative speed of VIi can be obtained, and even if the tape is fed at a higher speed, the head can read cue information.

In addition, in the rewind mode, the reel servo circuit (26) is operated under the control of the microcomputer (30) as described above.
The tape (15) is run at a constant speed of -m-N·Vt, and the drum servo circuit (29) moves the rotating head (
118) and (11B) are constantly rotated at a speed of v p'1, and as a result, the head trajectory angle θ at m-N times the speed becomes equal to the head trajectory angle θ at the N times speed, and The head trajectory angle θd and the angle of the trunk on the tape (R
2O angle) The size of the angle with θ8 | θT - θR | is a certain limit value, that is, the head trajectory angle θ which gives the limit that information that can be read continuously is meaningful information, and the angle θR of the track on the tape. Since the angle is not larger than the angle formed by the tape, a relative speed of m・■R'' that is m times faster than the relative speed ■R'' at N times the speed (that is, the relative speed VRO during normal playback) can be obtained, and the tape can be fed at a higher speed. The cue information can be read out using the head.

FIG. 2 shows a circuit configuration of a second embodiment of the present invention. In the figure, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

In this embodiment, a reel drive circuit (32) is provided, and a constant voltage is applied to the motor (27) at N times speed and m-N times speed.
, (28) for constant voltage driving.

As a result, the tape speed varies, for example, between Vt and N-Vt at N times speed in the fast forward mode, and between N-Vt and m-N-Vt when m -1'J times speed.

Note that during normal playback, the tape is driven by a capstan.

Further, a frequency divider (33) is provided on the output side of the PLL (not shown) of the electromagnetic conversion circuit (18), thereby dividing the frequency of the reproduced clock generated from the reproduced data by the PLL at a predetermined ratio. The output of the frequency divider (33) is the frequency-voltage (F
/V) is supplied to a conversion circuit (34), where the frequency signal is converted into a voltage signal.

The voltage signal from the conversion circuit (34) is supplied to one input side of the comparator (35), and a switch (
Reference power supply (37) supplied via (36) or (3
8) is compared with the reference voltage from 8). The reference voltage of the reference power source (37) is set to a voltage corresponding to the relative speed during normal playback (that is, the relative speed during N times speed), and the reference voltage of the reference power source (37)
The reference voltage 8) is set to a voltage corresponding to the relative speed at m-N times the speed. The switch (36) is connected to the reference power source (37) during normal playback and N times the speed, and is connected to the reference power source (38) during m·N times the speed. The comparison error signal from the comparator (35) is supplied as relative speed information to the drum servo circuit (29), and the motor (12) is controlled by the drum servo circuit (35).

In the m-N double speed fast forward mode, under the control of the microcomputer (30), the reel drive circuit (32) drives the motors (27) and (2B) at a constant voltage, and the speed of the tape (15) is N. It fluctuates between Vt and m-N·Vt. Then, the drum servo circuit (29) connects the head (IIA) to the head (IIA
), (IIB) speed m·VO' is controlled.

As a result, the head trajectory angle θ and the trunk angle θ on the tape are
Since the size of the angle 10T-0R with R does not exceed a certain limit value, the head can read the cue information even if the tape is fed at a higher speed.

In addition, in the rewind mode, the motors (27) and (28) are driven at constant voltage by the reel drive circuit (32) under the control of the microcomputer (30) as described above.
The speed of the tape (15) varies between -N-Vt and -m·N-Vt. The drum servo circuit (29) has a relative speed that is the reference voltage of the reference electric current FA (38), that is, m·■
The speed m·D'' of the heads (IIA) and (11B) is controlled via the motor (12) so as to be equal to R''. As a result, the size of the angle between the head trajectory angle θT and the trunk angle θR on the tape |θT−θR| does not exceed a certain limit value, so even if the tape is fed at a higher speed, the head will not be able to locate the cue information. Can be read.

〔Effect of the invention〕

As described above, according to the present invention, the drum rotational speed or tape speed is controlled so that the relative speed between the tape and the head during high-speed tape feeding is greater than that during normal playback and is constant, and the head trajectory angle θ and the tape Since the size of the angle θR of the trunk of |θT−θR| was set not to be larger than a certain limit value, the number of blocks that can be read continuously is at least l blocks.
Even if the tape is sent at a higher speed (ultra-high speed), specific information such as cue information can be read out with the 7-key.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing one embodiment of this invention, Fig. 2 is a block diagram showing another embodiment of this invention, Fig. 3 is a diagram for explaining the basic principle of this invention, and Fig. 4 is a block diagram showing another embodiment of this invention. The figure is a head locus diagram during fast forwarding and rewinding, and FIGS. 5 and 6 are diagrams for explaining the conventional example. (IIA) and (IIB) are rotating magnetic heads, (1
2). (27), (28) are motors, (13),
(14) is the reel, (15) is the magnetic tape, (26) is the beam servo circuit, (29) is the drum servo circuit, (3
0) is a microcomputer, and (32) is a reel drive circuit. Basic principle explanatory diagram Fig. 3 FF and ty' REWIMt A-k”m %fZlF
FH Helle Nine Rhon FF Time, ) - Todoroki IS Figure Figure 5 Payout Figure Figure 6

Claims (1)

[Claims] The drum rotation speed or tape speed is controlled so that the relative speed between the tape and the head during high-speed tape feeding is greater than that during normal playback and is constant, and the size of the angle formed by the head trajectory angle θ_T and the track angle θ_R on the tape is Sa｜θ_T−
A playback device characterized in that θ_R| is not larger than a certain limit value.