JPS61177082A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain noiseless slow reproduction by a storage means such as a digital memory by repeating the normal reproducing traveling of a magnetic tape and its rewinding traveling. CONSTITUTION:The normal reproducing traveling of the magnetic tape and its rewinding are repeated, and at the time of normal reproducing traveling, a regenerative signal is extracted as a regenerative video signal over one-field period and written in a memory 7. In a period excluding said one-field writing period, the contents of the memory 7 is read out and a regenerative video signal is formed. Consequently, noiseless slow reproduction can be attained without especially adding a low reproducing magnetic head and ordinary tracking adjustment can be omitted. In addition, the rewinding of the magnetic tape makes it possible to reduce the drop-out of a recording track corresponding to the regenerative signal of one field written in a memory at a normal reproducing traveling time.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic recording and reproducing device, and particularly to a magnetic recording and reproducing device that can realize noise-free slow reproduction using a storage means such as a digital memory. .

[Prior Art] Conventionally, a magnetic recording/reproducing apparatus (hereinafter referred to as "magnetic recording/reproducing apparatus") has a control track provided on a magnetic tape, records and reproduces a control signal on the control track, and controls the running of the magnetic tape using the control signal.
(referred to as VTR) is known. In such a control signal type VTR, one method for performing slow playback without noise is to drive the tape intermittently during slow playback by repeating running and stopping. In such a method, in order to obtain a noise-free reproduced image, the positional relationship between the recording track and the rotary head must always be within a range where no noise appears on the reproduced screen when the tape is stopped. In order to obtain this positional relationship, the control signal played during tape running is used as track position information, and the tape running amount of this control signal detection model is controlled to stop the tape at a position where no noise appears on the screen. That's what I do.

FIG. 4 is a diagram for explaining tape running control during slow playback of a conventional VTR. In the figure, Fig. 4(a) shows the torque output Mt of the tape drive motor that drives the capstan shaft used for tape running, Fig. 4(b) shows the tape speed V, and Fig. 4(C) indicates the reproduction output of the control signal C recorded in the running direction of the tape. As is clear from FIG. 4, in the conventional control method for the device, the magnetic tape is accelerated from time to to time t, then run at a constant speed, and when the control signal C is detected at time t2, a delay occurs. After opening ((s j2), braking is started, and at time t4 when the tape speed V is approximately O, the braking is stopped to stop the magnetic tape.

Here, at the time of the above-mentioned delay 1ffi (j s −j 2
) is called a tracking delay time, and by increasing or decreasing this time, the amount of tape feeding after the control signal C is detected increases or decreases. This time can usually be adjusted using a variable resistor, and this can be adjusted to obtain the best reproduced image.

In other words, the magnetic tape can be stopped at the optimum tape stop position.

[Problems to be Solved by the Invention] As described above, in the conventional VTR, the tracking delay time must be adjusted by the user, which is inconvenient. Furthermore, since the relative speed between the magnetic tape and the rotary head changes between when the magnetic tape is running and when it is stopped, the period of the playback horizontal synchronization signal changes, and the playback screen changes every time the magnetic tape is driven. There were drawbacks such as swaying. In addition, in order to achieve slow playback without blurring, it is necessary to use two magnetic heads with the same azimuth to perform playback when the magnetic tape is stopped.
In addition to the two magnetic heads for normal recording and reproduction, one or two slow magnetic heads are required.

Therefore, the main purpose of the present invention was to eliminate the problems of the conventional technology, and to provide a slow magnetic radiator for slow noiseless playback without rolling or blurring without the need for tracking adjustment. The purpose of the present invention is to provide a magnetic recording and reproducing system that can be realized without any problems.

[Means for Solving the Problems] In slow playback in the magnetic recording and reproducing apparatus according to the present invention, the magnetic tape is caused to run during normal playback based on the normal playback running signal generated from the normal playback running signal generating means. The running bar means repeats a state in which the tape is rewound in the opposite direction to the tape traveling direction during normal playback in response to a rewind signal generated from the rewind signal generating means, and the magnetic head is moved during normal playback. The reproduced signal is processed by a signal processing means and used as a reproduced video signal, and the processed signal is written into a storage means such as a digital memory for one field period, and during the period excluding the writing period to the writing means. , the contents of the storage means are read out by changing the switch, and the contents are outputted as a reproduced video signal.

[Operation] In the slow reproduction according to the present invention, noise-free slow reproduction can be realized by repeating the normal reproduction run and the rewind run of the magnetic tape using a storage means such as a digital memory.

[Embodiment of the Invention] An embodiment of the invention will be described below with reference to the drawings.

FIG. 1 is a schematic block diagram of an embodiment of the present invention.

First, the configuration will be explained with reference to FIG. In addition, in this FIG. 1, only the reproduction system of the VTR is shown.
Recording system is omitted. The reproduction outputs of the rotating magnetic heads 1a and 1b are given to head amplifiers 2a and 2b, respectively. Head amplifiers 2a and 2b are rotary magnetic heads 1a and 1b.
This is to amplify the reproduced signals output from each.

The respective outputs of the head amplifiers 2a and 2b are selected by a switch 3 which is switched according to a head switching signal H8W, and are applied to a reproduction processing circuit 5. Reproduction processing circuit 5
performs reproduction signal processing regarding the luminance signal and color signal included in the reproduction signal, and outputs a reproduction video signal. The reproduced video signal processed by the reproduction processing circuit 5 is applied to one terminal 91 of the switch 9 and also to the A/D converter 6.

The A/D converter 6 converts the reproduced video signal into a digital signal, and supplies the converted digital signal to the memory 7. The memory 7 is a digital memory capable of storing one field's worth of video signals, and constitutes a storage means. The digital signal read from the memory 7 is given to the D/A converter 8 and converted into an analog signal. This analog signal is the other terminal 9 of the switch 9 mentioned above.
given to 2. This switch 9 is switched to the output side of the reproduction processing circuit 5 when a digitized video signal is written to the memory 7, and is switched to the output side of the D/A converter 8 when a digital signal is read from the memory 7. When the output terminal 100 is switched to the side, the reproduced video signal is output from the output terminal 100.

The aforementioned head switching signal H8W is also given to the waveform shaping circuit 10. This waveform shaping circuit 10 generates a head switching signal H8.
A relatively short width pulse signal is output at the rising and falling points of W. The pulse signal PO output from the waveform shaping circuit 1o is connected to the set input terminal of the flip 70 knob 11, the first timing circuit 13, and the second timing circuit 13.
timing circuit 16. A slow reproduction command signal SL input to an input terminal 32 is applied to a reset input terminal of the flip-flop 11.

This slow reproduction command signal SL is also applied to one input terminal of the AND gate 12. The Q output of the flip-flop 11 is applied to the other input terminal of the AND gate 12.

The AND game 12 outputs a slow reproduction command signal SL when the flip-flop 11 is set. The output of this AND gate 12 is applied to a first timing circuit 13, inverted by an inverter 14, and applied to one input terminal of an OR gate 15. This OR
A first timing circuit 13 is connected to the other input terminal of the gate 15.
An output signal P is given from. And OR gate 1
The output of 5 is given to the memory 7 as a write signal, and also given to the switch 9 as a switching signal.
It is also provided to the timing circuit 16 of.

A control signal CTL is applied to the travel control tg+ system W17 via an input terminal 34. This traveling side a device f
Reference numeral 17 outputs a command signal Vf for controlling the running of the magnetic tape to the running state during normal reproduction. This command signal vf is given to the motor drive circuit 19 via the switch 18. The switch 18 is turned on and off by the output signal P from the second timing circuit 16. Further, the motor drive circuit 19 is supplied with an output signal P from the second timing circuit 16 via an inversion circuit 21. The reversing circuit 21 applies reversing torque to the tape drive motor 20 in order to cause the magnetic tape to run in a direction opposite to that during normal reproduction. The motor drive circuit 19 is for traveling 1
The tape drive motor 20 is controlled to the running state during normal playback according to the command signal Vf output from the 1i1J'a device 17, and the tape drive motor 20 is controlled to the normal playback running state according to the reversing torque from the reversing circuit 21. The vehicle is run in the opposite direction from the current running state. This tape drive motor 2
A frequency generator 22 is provided which generates a frequency signal proportional to the rotation of the capstan shaft in relation to the rotation of the capstan shaft, and the frequency signal generated by the frequency generator 22 is connected to the aforementioned traveling control m+.
device 17.

The recording system of the VTR shown in FIG. 1 is a rotating two-head type helical scan in which one field consists of one track.

FIG. 2 is a time chart for explaining the operation of FIG. 1. Next, with reference to FIG. 1 and FIG. 2, a specific operation of an embodiment of the present invention will be described. first,
FIG. 2(a) is a diagram showing time, and FIG. 2(b) is a head switching signal H8W given to the terminal 31 in FIG. 1, and the period of high level and low level in this head switching signal H8W. are rotating heads 1a and 1b, respectively.
This is one field period during which the signal is reproduced by.

Now, before time t0, the normal playback mode is in effect, and at time t0, the slow playback command signal SL is input to the terminal 32. This slow playback command signal SL is shown in Figure 2(d).
As shown in FIG. 2, for example, in the normal playback mode, the signal is at a low level, and in the slow playback mode, the signal is at a high level.

On the other hand, the head switching signal H8W applied to the terminal 31 is input to the switch 3, which controls the outputs of the head amplifiers 2a and 2b to be switched according to the head switching signal H8W, and is also applied to the waveform shaping circuit 10. The waveform shaping circuit 10 is composed of, for example, a gate circuit, and a second
As shown in Figure (C), in synchronization with the rise and fall of the head switching signal H8W, a pulse signal Po rising to a high level is output.

The pulse signal P from the waveform shaping circuit 10 is applied as a set input to a flip-flop 11, and a slow reproduction command signal SL is applied to the reset input of this flip-flop 11 via a terminal 32. In addition,
This flip 70 knob 11 is operated by the rise of the set input and reset input. Therefore, the flip-flop 11 is set by the pulse signal P0 from the waveform shaping circuit 10, and its Q output becomes as shown in FIG. 2(e). The Q output of the flip 70 knob 11 and the slow reproduction command signal SL are input to the AND gate 12, and the output is as shown in FIG. 2(f). That is, the output of the AND gate 12 switches from low level to high level at the first head switching time t after time to.

The output signal of the AND gate 12 and the output pulse signal P0 of the waveform shaping circuit 10 are input to the first timing circuit 13. This first timing circuit 13 counts the number of switches of the pulse signal P0 from low level to high level, that is, the number of pulses, in synchronization with the rise of the output signal of the AND gate 12 from low level to high level, Every time the count value reaches a predetermined value N0, a high level signal P is output for, for example, one field period (js jn>. This output signal P is as shown in FIG. 2(h).
It becomes as shown in . Then, the output of the AND gate 12 is inverted by the inverter 14, as shown in FIG. The output signal P2 is outputted through the output signal P2 as shown in FIG. 2(1).

The output signal P2 of the OR gate 15 mentioned above is applied to the memory 7, serves as a write/read control signal, and also serves as a write/read control signal.
It also serves as a switching signal. That is, while the output signal P2 is at a high level, the memory 7 is in the write state, and
The switch 9 is switched to the contact 91 side. As a result, the output signal of the head amplifier 2a or 2b selected by the switch 3, that is, the reproduction signal of the rotary head 1a or 1b, is processed by the reproduction processing circuit 5, and the signal is digitized by the A/D converter 6. The signal written into the memory 7 and processed by the reproduction processing circuit 5 is outputted to the output terminal 100 via the switch 9 as a reproduced video signal.

On the other hand, during the period in which the output signal P2 of the OR gate 15 is at a low level, writing to the memory 7 is not performed and the switch 9 is switched to the terminal 92 side.

As a result, the contents of the memory 7 are read out, and the D/A change 1
The digital signal is converted into an analog signal by the fi8, and outputted from the output terminal 100 as a reproduced video signal.

The second timing circuit 16 also includes an OR gate 15.
The output signal P2 of the second timing circuit 16 and the pulse signal P0 of the waveform shaping circuit 1o are input, and the output signals P and P4 of the second timing circuit 16 are outputted when the output signal P2 of the OR gate 15 changes from high level to low level. When you switch to
Synchronize with that and reach a high level. Then, the number of pulses of the pulse signal P0 from the waveform shaping circuit 10 is counted, and when the counted value reaches a predetermined value N2, that is, at time t, the output signal P becomes low level, and the counted value When becomes N, that is, at time t2, the output signal P
4 becomes low level. In addition, prescribed 1! [N2 and N
, are set to N+ <N2 <No. The time chart of these output signals P and P4 is shown in Figure 2 (j>,
It is shown in (k).

In addition, in this Figure 2 (j) and (k), N2-N
It is set to ++2.

The output signal P outputted from the second timing circuit 16 described above is used as a switching signal for the switch 18. That is, during the period when the output signal P is at low level,
The switch 18 becomes conductive. Then, the command signal vf from the travel control device 17 is given to the motor drive circuit 19 to drive the tape drive motor 20. Also, the output signal P.

The switch 18 is in a non-conductive state during the period when is at a high level. Here, the running control device 17 connected to the terminal 181 of the switch 18 changes the running speed of the magnetic tape (not shown in FIG. 1) to the normal tape running speed and controls the position of the magnetic tape. Then, a command signal vt is outputted to control the tape running during normal playback. The running tIIJiII device 17 receives the output of a frequency generator 22 which generates a signal with a frequency proportional to the number of revolutions of a capstan shaft (not shown), that is, the tape running speed, and controls the running of the magnetic tape. Further, a control signal CTL, for example, which is reproduced when the tape is running as magnetic tape position information, is input to the running control device 17 via a terminal 34, and this control signal CTLI
By controlling the transfer of the magnetic tape based on , -, tape running control during normal playback is performed. In addition to the above-mentioned control signal CTL, a pilot signal recorded on a recording track in a superimposed manner with a video signal may be used as the magnetic tape position information.

On the other hand, the output signal P output from the second timing circuit 16 is input to the inverting circuit 21, and one output signal P,
When the switch 18 is in a non-conducting state while the output signal P4 is at a high level, an inverting command is given from the inverting circuit 21 to the motor drive circuit 19 while the output signal P4 is at a high level, and the tape drive motor 22 operates normally during playback. Generates rotation torque in the opposite direction to the rotation direction.

The above series of operations will be explained in more detail.

By time. When the slow reproduction command signal SL is applied at , the output signal P2 of the OR gate 15 maintains a high level state until the first head switching time t after time to. Furthermore, since the output signals P, , P, of the second timing circuit 16 remain at low level, the time t
Normal playback is performed until . Then, the output of the reproduction processing circuit 5 which has undergone signal processing regarding the luminance signal and the color signal for the reproduction signal of one field period by the rotary head 1a ending at the time [,] is output to the terminal 100.
It is output as a playback video signal to the memory 7.
One field of signals digitized by the A/D converter 6 is written into the field.

At time [, the output signal P2 of the OR gate 15 switches from high level to low level, and the output signals P, , P, of the second timing circuit 16 both switch from low level to high level. Therefore, writing to the memory 7 is not performed, the switch 9 is switched to the terminal 92 side, the contents of the memory 7 are read out, and the signal converted into an analog signal by the D/A converter 8 is transferred from the terminal 100 to the reproduced video signal. is output as On the other hand, since the output signal P3 of the second timing circuit 16 shows a high level at the time ([e f,), the switch 18 becomes non-conductive at the time (t a −t 1). Therefore, the command signal Vf output from the travel control device [17] is no longer given to the motor drive circuit 19, and the motor drive circuit 19 receives the output signal P4 from the inverting circuit 21 from the second timing circuit 16 (t). 2
A corresponding inversion command signal is given during the high-level signal period spanning -t + ). In other words, time t
, the tape drive motor 22 generates a rotational torque in the opposite direction to the rotational direction during normal reproduction up to that point. Thereby, the magnetic tape is transferred to the time (t2 t
In o), the running speed during normal playback decreases,
Further, the above-mentioned predetermined INN is set to determine time t2 so that the vehicle travels slightly in the opposite direction to that during normal playback.

At time t2, when the reversal command signal becomes low level, the tape drive motor 22 no longer generates rotational torque, and the running speed of the magnetic tape that was running in the opposite direction gradually decreases. Time t.

At the time point, the magnetic tape has already stopped or is running in the reverse direction at a very slow speed, and the magnetic tape is in a spring return state.

time【. When this happens, the output signal P of the second timing circuit 16 switches from high level to O- level, so that the switch 18 becomes conductive. Therefore, the command signal Vf from the travel control device 17 is given to the motor drive circuit 19, the tape drive motor 20 is turned on, and the magnetic tape, which had been rewound up to time t, resumes normal reproduction travel. become. Note that the tape for normal playback enters the running state after the time required from time t8 until the normal running state is stabilized, which is the so-called servo pull-in time.

Furthermore, in the first timing circuit 13, at time t4, when the number of pulses of the pulse signal P from the waveform shaping circuit 10 after time t reaches a predetermined value No (No > N1, N2), the first timing circuit 13 The output signal P of the timing circuit 13 changes from low level to high level, and at time 1, one field WArIl after time t4.
．． Outputs a high level signal until . therefore,
At a time <ts t, corresponding to one field period, the switch 9 is switched to the terminal 91 side. As a result, the output of the reproduction processing circuit 5 regarding the reproduction signal for one field by the rotary head 1a is directly transmitted to the terminal 100.
output as a playback video signal.

At the same time, the output of the reproduction processing circuit 5 is digitized by the A/D converter 6 and written into the memory 7.

Note that the values of the predetermined values N+, N2, and No that determine each of the above-mentioned times t2+'e+t4 are such that No>N2
>N+, and (No −N2)
In other words, the value of time (to-ts) is set to a value longer than time t, which is the time required to achieve normal regeneration travel control after that, that is, the servo pull-in time.

From the above time t, 1. The series of operations in the period up to time t is repeated from time t onwards, and the subsequent times js+tt, tg, and tg are respectively from time t to 1.
This corresponds to "2*ta+"4+t.

FIG. 3 is a diagram showing the running state and recording tracks of the magnetic tape explained in FIGS. 1 and 2. In FIG. 3, 50 indicates a magnetic tape, and 51 indicates the running direction of the magnetic tape during normal reproduction. Also, recording track T3. .

Tea and TRI indicate recording tracks recorded by the rotary head 1a, and recording tracks Tt 2 r Tl 4 r v and l+ indicate tracks recorded by the rotary head 1b, respectively. As mentioned above, the magnetic tape 50 enters the rewinding state once from time t to 1 s, and then returns to the normal playback state again. 50 is L+ -2Lp in the longitudinal direction
(Lp indicates the distance in the longitudinal direction of the track pitch.) After traveling a distance of t! Similarly, the distance between ts and ts is 12=2LP.

In FIG. 5, the recording track Tl+1T indicated by diagonal lines
R31TIIs are the time t, the last one field period in the previous normal playback (t+jL), and the one field period in the normal playback from time [4 to t5 (j
s j<>, 1 during normal playback from time t8 to t9
In the field period 111 (t9-ta), the reproduced video signal is output from the terminal 100, and
This is a recording track of a video signal written into the memory 7. Then, from time t1 to t4 and from time [, to t6, the recording track TIl
, and Taz are outputted from the terminal 100 as a reproduced video signal. In this way, the slow playback according to the time chart shown in Figure 2 is performed every 5 frames (one frame is 2 field periods), so it can be said to be a so-called 115 slow playback. .

As described above, in the slow playback in one embodiment of the present invention, the normal playback run of the magnetic tape and the rewinding of the magnetic tape are repeated, and during the normal playback run, the playback signal is taken out as a playback video signal over one field period, and is 7, and during the period excluding the above-mentioned 1 field write period, the contents of the memory 7 are read out and used as a playback video signal, so noiseless slow playback is performed without adding a magnetic head for slow playback. This also eliminates the need for conventional tracking adjustment. In addition, since the magnetic tape is rewound, it is possible to reduce the possibility that the recording track corresponding to one field of playback signal written to the memory 7 during normal playback is missing, and is not played back during slow playback. The number of recording tracks can be reduced. Furthermore, even when transitioning from the normal reproduction mode to the slow reproduction mode, it is possible to realize a mode transition in which excessive noise does not appear.

In addition, in the above-mentioned embodiment, at the predetermined values N and N2,
The value was set to N2-Nl +2, but N2 is N
It may be a value that satisfies 2≧N1.

Further, in the above-mentioned embodiment, the case where the number of heads is two has been described, but the number of heads is not limited to two. Furthermore, the present invention is not limited to the case where one field consists of one track, but is also applicable to segment-type VTRs and channel-split-type VTs where one field consists of multiple tracks.
Also in R, the same effect as in the above embodiment can be obtained. Furthermore, in the above embodiment, an analog recording method is used in which analog signals are recorded on a magnetic tape, but the VT is a digital recording method in which digital signals are recorded on a magnetic tape.
This invention can also be applied to R.

Furthermore, in the above-described embodiment, the timing at which to start writing the reproduction signal for one field period into the memory 7 is determined by the counted value of the head switching number No., in other words, by time. The timing of starting recording may be managed by the amount of tape travel. For example, the control signal CTL on the tape during rewinding from time t to time t is reproduced by a magnetic head such as an MR head that can obtain an output level regardless of the tape running speed, and the pulse Count and memorize the number M (positive integer), and after the start of normal driving at time [,
Control signal C corresponding to M+α (α: positive integer)
By counting the number of TL pulses, the reproduced signal may be written into the memory 7 over the subsequent head switching period of the first field and output as a reproduced video signal. In other words, according to this embodiment, the tape is always returned to the vicinity of the tape position before rewinding (the state in which M is counted), and then α is counted in the normal playback running direction before being written to the memory 7. 7, it is possible to manage to write a recording track corresponding to one field's worth of reproduction signal at the same interval on the magnetic tape every time. Note that the value of α is set so that when M+α is counted, the magnetic tape is already in the running state during normal reproduction.

[Effects of the Invention] As described above, according to the present invention, during slow playback, the running state during normal tape playback and the slightly rewound state are repeatedly run, and during normal playback, the normal playback signal for one field period is is used as a playback video signal and written to a storage means such as a digital memory, and during periods other than the writing period of one field, the contents of the storage means are read out and output as a playback video signal, so slow playback is possible. It is possible to achieve slow playback without noise, blur, or lateral shaking without adding an additional head. Furthermore, it is possible to realize a playback screen with less missing information during slow playback. Furthermore, the unique effect of eliminating the need for tracking adjustment can also be achieved.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of an embodiment of the present invention. FIG. 2 is a time chart for explaining the operation of FIG. 1. FIG. 3 is a diagram for explaining the time chart shown in FIG. 2. FIG. 4 is a diagram for explaining running control of a magnetic tape during slow playback in a conventional VTR. In the figure, 1a and 1b are heads, 2a and 2b are head amplifiers, 3, 9.18 are switches, 5Lt reproduction processing circuit, 6 is an A/D converter, 7 is a memory, 8 is a D/A converter,
10 is a waveform shaping circuit, 11 is a flip 70 block, 12 is an AND gate, 13 is a first timing circuit, 14 is an inverter, 15 is an OR gate, 16 is a second timing circuit, 17 is a running fIIIj device, 19 is a A motor drive circuit, 20 a tape drive motor, 21 an inversion circuit, 22
indicates a frequency generator.

Claims (1)

[Scope of Claims] A slow motion device that repeats the running state of the magnetic tape during slow playback between the running state during normal playback and the state where the magnetic tape is rewound by running in a direction opposite to the running direction of the magnetic tape during normal playback. A magnetic recording/reproducing device having a playback mode, comprising: normal playback running signal generating means for generating a normal playback running signal for running the magnetic tape in a normal playback state; and generating a rewinding signal for rewinding the magnetic tape. rewinding signal generating means for causing the magnetic tape to run normally in response to a normal playback running signal from the normal playback running signal generating means; a running control means for rewinding the tape; a magnetic head for recording signals on the magnetic tape and reproducing the recorded signals; a signal processing means for processing the signals reproduced by the magnetic head; At the time of reproduction, a storage means for writing the output of the signal processing means obtained by processing the reproduction signal of the magnetic head in one field period; a write/read control means for controlling writing and reading of the storage means; In accordance with the output of the read/write control means, during the write period to the storage means, the output of the signal processing means is output as is as a reproduced video signal, and during the period other than the write period to the storage means, A magnetic recording/reproducing device, comprising: a switch for outputting an output read from the storage means as a reproduced video signal.