JPS6079880A - magnetic recording and reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic recording and reproducing device designed to reduce the horizontal sway of a brush stroke when performing slow-motion reproduction by running a magnetic tape intermittently. .

[Takehara of invention]

Conventionally, tracks are formed diagonally on a magnetic tape.
In the so-called helical scan type magnetic recording and reproducing apparatus, a reproduction method called a noiseless slow motion reproduction method is known. Such a restraint system reproduces a magnetic tape by running it intermittently, and when the magnetic tape is stopped, the same track is repeatedly scanned for reproduction with a rotating head, and when this track is reproduced and scanned a predetermined number of times. , the magnetic tape is transferred a fixed amount, and the next track is similarly scanned for fHa repeat reproduction. In this case, the magnetic tape is not transferred instantaneously by a predetermined amount, but rather takes a certain amount of time.

FIG. 1 is a graph showing the intermittent running of the magnetic tape, with the horizontal axis representing time t and the vertical axis representing the running speed vt of the magnetic tape.

In the figure, the running speed of the magnetic tape is vtl (however,
During the stop period TIl at vj1=:O), as described above, the rotating head recycles the same track a predetermined number of times,
The magnetic tape is driven from time 1G when this stop period T ends, and the running speed Vl of the magnetic tape increases bi-dimensionally.

When the running speed vt of the magnetic tape reaches a steady speed vt2 (this steady speed V12 is generally the running speed during normal reproduction) (time t1), a steady speed state Tc is reached and the magnetic tape runs at a running speed Vj2. . Next, time t
, a torque in the opposite direction is applied to the capstan motor, the magnetic tape is decelerated, and at time t3 a stop period Tll is entered and the rotary head repeatedly reproduces the next track.

In this manner, the magnetic tape runs for a total of (tsto) time as the rotating head moves from one track to the next. This time is usually about 60 to 79 m5 ec, and during this time the rotary head continues to scan the magnetic tape for reproduction and to reproduce images. It goes without saying that the slow ratio is determined by the number of reproduction scans of the same track during the stop period T6.

By the way, such a noiseless slow motion state (hereinafter referred to as normal playback state, although this state includes a period in which the running speed changes) is based on the relative speed between the rotating head and the magnetic tape (hereinafter referred to as head-tape relative speed). ) There is a discrepancy. Now, the relative speeds of the head and tape in the still image writing state and the normal playback state are Vt+ and Vt, respectively.
2, there is a relationship as shown in FIG. 2 between the magnetic tape running speed Vi and the head/tape relative speed. Therefore, when transferring from the still image playback state to the normal playback state, the frequency of the horizontal synchronization signal to be played changes,
Play 18! ! Lateral shaking will occur at +1 E.

In order to eliminate this problem, the relative velocity of the head and tape must be kept constant regardless of whether the magnetic tape is running or stopping. In the case of Fig. 2, l Vt21 <
l vtx I, therefore, in normal playback conditions, it is necessary to increase the rotational speed of the head cylinder to increase the relative speed of the tape head.

FIG. 3 shows a conventional magnetic recording/reproducing apparatus which maintains the head/tape relative speed constant during noiseless slow motion control reproduction as described above. In the figure, 1 is an input terminal, 2 is a system control circuit, and 3 is a head cylinder motor drive circuit.

4 is a pulse signal generation circuit, 5 is a carburetor tongue motor, 6 is an addition circuit, 7 is a head cylinder motor, 8 is a capstan motor, 9 is a magnetic tape, 10 is a rotary head, and 11 is a head cylinder. .

FIG. 34 is a timing chart for explaining the entire operation of FIG. 3, and signals corresponding to those in FIG. 3 are given the same reference numerals. Also, the time "Or "tr" in FIG.
S corresponds to time "On" tr t3 in FIG. 1 (hereinafter referred to as the same).

In FIGS. 3 and 4, Stationary II! In one reproduction state, the capstan motor 8 is stopped, and therefore the magnetic tape 9 is stopped (stop period Tg in FIG. 1). On the other hand, the head cylinder motor drive circuit 3 receives the head cylinder Ig generated from the system control circuit 2.
? 6 command, it is in the operating state and the krA signal is being generated, so that the head cylinder motor 7 rotates at a predetermined number of rotations and the rotary head reproduces and scans the magnetic tape.

At time t0, input terminal 1 is switched to system control circuit 2.
Based on this, the system control circuit 1 sends a capstan motor drive command e to the pulse signal generation circuit 4 and the capstan motor P movement circuit 5.

The capstan motor jiia M command e has a level e at time 1o-12 and a level e at time t, as shown in Figure 4.
It has level e2'ik at 2~t. When the capstan motor drive command e is at level e, the capstan motor E movement circuit 5 drives the capstan motor 8 in forward rotation, and as a result, as shown in FIG. 1, the magnetic tape is rotated at time t. The vehicle starts traveling at a constant speed, increases the traveling speed, and starts traveling at a steady speed V < 2 from time t. When the capstan motor drive command e is at the level e, the capstan motor 8 is driven in reverse, and for this reason, as shown in No. 10, the magnetic tape is gradually decelerated from time t, and the running speed Vt becomes Vtt ( That is, at time t3 when the value becomes zero),
The capstan motor drive command e reaches level e representing a stop command, and the capstan motor 8 and therefore the magnetic tape 9 stop.

On the other hand, the pulse signal generation circuit 4 generates a signal at time t based on the capstan motor drive command e. A pulse signal f with a time width of +r2 and an amplitude of F is generated, which is delayed by a time T from . This pulse signal f is at time to-t.

The signal is generated during this time, is added to the drive signal J from the head cylinder motor drive circuit 3 in the adder circuit 6, and is supplied to the head cylinder motor 7. Therefore, the number of rotations of the head cylinder is increased by pulse No. 41f, and the relative speed of the head and tape in the normal playback state is corrected.

The above is a tape made by intermittent running of the company tape.

This may be due to the lateral shaking of both playback parts caused by fluctuations in the relative speed of the head.In addition, the lateral shaking of the tape is caused by changes in the tension of the magnetic tape as it runs. Variations in load torque occur, but they also occur due to uneven rotation of the head cylinder motor due to variations in tape load torque.

However, in the conventional magnetic recording system, regardless of the fluctuation of the tape load torque of the head cylinder motor, the pulse width is partially set as shown in FIG. Removes horizontal shaking from the playback image (
Because of this, the tension of the magnetic tape is high, and the rotational unevenness of the head cylinder due to fluctuations in tape load torque during noiseless slow-motion playback is also large, making it difficult to eliminate horizontal vibration in the reproduced image. could not.

In general, there are variations in the tension of the magnetic tape between magnetic recording and reproducing devices, and the tension of the magnetic tape during intermittent running varies depending on the amount of winding of the magnetic tape on the tape reel. Therefore, horizontal shaking inevitably occurs in the reproduced image.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic recording and reproducing apparatus which eliminates the drawbacks of the prior art described above and is capable of suppressing horizontal shaking of a reproduced image at a high degree when reproducing a magnetic tape by running it intermittently. be.

[Summary of the Invention] In order to achieve this object, the present invention detects and stores periodic fluctuations in a horizontal synchronizing signal reproduced each time a magnetic tape is run, and detects and stores periodic fluctuations in a horizontal synchronizing signal reproduced each time a magnetic tape is run, and detects and stores periodic fluctuations in the horizontal synchronizing signal reproduced each time a magnetic tape is run, and detects and stores periodic fluctuations in a horizontal synchronizing signal reproduced every time a magnetic tape is run. The special feature is that the roll compensation signal that compensates for head/tape relative speed fluctuations during tape running is changed to compensate for head cylinder motor rotational irregularities caused by fluctuations in tape load torque. be.

[Embodiments of the invention]

Hereinafter, all drawings of embodiments of the present invention will be described.

′? 5 is a block diagram showing an embodiment of the magnetic recording and reproducing device according to the present invention, in which 12 is a head switch circuit, 13 is a video signal processing circuit, 14 is an Oka M fluctuation detection circuit, and 15 is a correction signal. a generation circuit, 16 is an amplifier;
Parts corresponding to the figures are given the same reference numerals, and some explanations will be omitted.

FIG. 6 is a waveform diagram showing the rolling correction signal f of FIG.

In Figure m5 and Figure 6, when the noiseless slow motion playback mode is set, the capstan motor 8 stops and the still image playback mode occurs, and the head cylinder motor 7
is rotated by a drive signal J from the head cylinder motor drive circuit 3, and the same track on the recording tape 9 is repeatedly reproduced and subjected to constant distortion by the rotary head 1o mounted on the head cylinder 11.

When the regenerative constant distortion of the rotary head 10 is performed a predetermined number of times, a travel command g is sent from the input terminal 1 to the system control circuit 2, and the system control circuit 1 and the same circuit 2 issue a capstan motor drive command to the capstan motor drive circuit 5. e to the correction 4Fi signal generation circuit 15? iii Send a positive signal generation command d. As a result, the capstan motor 8 rotates, and the magnetic tape 9 runs at the running speed shown by AIIA, entering the normal playback state.

On the other hand, the correction signal generation circuit 15 outputs a pulse width T2 after a predetermined time Ill 1 delay than the capstan motor drive command e.
This pulse signal is amplified by an amplifier 16 to obtain a first roll correction signal f having an amplitude F. This rolling correction signal f is used for rolling correction 1 in Figure 6.
It is indicated as 100 No. f. This roll correction signal f is calculated by adding 34
．． It is added to the drive signal J in the circuit 6 and supplied to the head cylinder motor 7. This lateral vibration correction (ci number f1 is set to pulse 1 ttm pulse oscillation -F, etc.) so as to correct the fluctuation x + Mj of the relative velocity of the head and tape when the normal playback state is entered, and therefore , 1st normal playback condition! 19 after head-tape relative speed in mind
The horizontal shaking of the reproduced image 1 ice accompanying this is corrected.

The video signal from the rotating head 10 is turned into a continuous signal by the head switch circuit 12, and is also supplied to the video signal processing circuit 13.The video signal processing circuit 13 separates the horizontal synchronization signal. This horizontal synchronization +a'@a is supplied to a periodic fluctuation detection circuit 14 consisting of a frequency-voltage converter, for example.The periodic fluctuation detection circuit 14 detects the periodic fluctuation of the horizontal synchronization signal, and this period A detection signal bf representing the fluctuation is supplied to the system control circuit 2.

When there is a variation in tape load torque in the normal playback state, there is a variation in the period of the horizontal synchronizing signal a. The system control circuit 2 is configured with a microcomputer, for example, and has a memory function, and the system control circuit 2 receives a detection signal representing the periodic variation of the horizontal synchronization signal a in the normal playback state. be remembered.

Normally, when the regeneration state ends, the capstan motor 8
stops and enters a stationary state. The rotary head 10 repeatedly moves to the next trunk for still image reproduction.

Next, a running command g is sent to the system control circuit 2 from the input terminal 1.
When the signal is sent, the capstan motor 8 is driven to rotate in the same manner, and the normal reproduction state for the second scan is established. At the same time, the system flj control circuit 2 sends a correction signal generation command d to the correction signal generation circuit 15, which corresponds to the detection signal stored in the previous normal playback state. As a result, a roll correction signal f with set amplitude and pulse width is obtained. With respect to the horizontal vibration correction signal f1 in the previous normal playback state, the vibration correction signal f1 is changed from vibration 11- to F' (M is shown as signal f! in FIG. 6, and the amplitude is changed to F'.
', and the roll correction year in which the pulse width changed from TI is also shown as a signal f.

The roll correction signal f thus corrected to 5 is the drive signal J
is added to the head cylinder motor 7, and the U rotation speed of the rotary head 10 is controlled so that the regeneration Ii! ! I(9
) is corrected.

Hereinafter, similarly, the periodic variation detection circuit 14 for each normal reproduction state
A periodic fluctuation in the horizontal synchronizing signal @a is detected, and a detection signal representing this periodic fluctuation is supplied to the system control circuit "kr2. With this detection signal S, the detection signal in the previous normal reproduction state is corrected, It is used to form the waveform of the UAi and shake ili1 positive signals f in the next normal playback state.In this way, the roll correction signal is corrected for each normal playback state, and the roll correction of the reproduced image is corrected. .

FIG. 7 is a block diagram showing another embodiment of the magnetic recording/reproducing apparatus according to the present invention, in which 17 is a capacitor, 18 is a limiter, 19 is an amplifier, 20 is an analog-to-digital converter, and 21 is an output terminal. , the parts corresponding to those in Figure 5 are given the same reference numeral r, and some explanations will be omitted.

FIG. 8 is a waveform diagram of the rolling correction signal f shown in FIG.

In FIG. 7, as in the embodiment shown in FIG. 5, when the normal reproduction state is set, a detection signal bIJ''- representing a periodic change 1AJJr of the horizontal synchronizing signal a is obtained from the periodic fluctuation detection circuit 14. Periodic fluctuation detection The circuit 14 is a frequency-voltage conversion circuit, and converts the output signal from the output terminal 21 into the frequency offset amount of the reproduced horizontal synchronizing signal in the high-speed reproduction mode.
It is also possible to detect it.

The DC component of the detected signal M@b from the periodic variation detection circuit 14 is removed by a capacitor 17, and is supplied to a limiter 18 formed of, for example, a diode.

The limiter 18 suppresses the alternating current voltage fluctuation of the detection signal within the dynamic range of the analog-to-digital conversion 6 in the next stage, and when this voltage fluctuation pressure fluctuation becomes excessive, Works well to limit upper or lower limits.

The detection signal from the limiter 18 is amplified by the amplifier 19,
The amplified detection signal i is converted into a digital signal j by an analog-to-digital converter and supplied to a system control circuit 2 which performs a storage function.

Therefore, in the first normal reproduction state, the head cylinder motor 7 is supplied with a rolling correction signal f having an amplitude F and a pulse width T2, as shown as a signal f1 in FIG. 8, and as a result, the amplifier 19, if a detection signal i is obtained whose width is equal to y to the signal f, as shown as No. 4i in FIG. It is stored, and in the next normal playback state, the amplitude of the roll correction signal f is corrected, and the signal f with the amplitude F' shown in FIG. 8, which corresponds to the stored detection signal i! bawl.

Also, during the first normal reproduction state, the period of the detection signal i from the amplifier 19 is the pulse width of the roll correction signal (FIG. 8 fi) at this time, as shown as signal 12 in FIG. In the next normal playback state, the roll correction signal f has an amplitude of F' and a pulse width of F' and a pulse width, depending on the amplitude and period of the detection signal l, as shown as signal f in FIG. is corrected as T, /.

Hereinafter, in each normal playback state, the lateral return correction 15 is performed according to the detection signal i detected during the previous normal playback state.
The amplitude and pulse width of the signal f are corrected, and the horizontal shaking of the reproduced image 12 is corrected. Of course, in this embodiment as well, in the second and subsequent normal playback states, the digital signal j from the analog-to-digital converter is used to convert the system system (similar to that stored in the If11 circuit 2) during the previous normal playback state. It goes without saying that the digital signal is corrected and corrected.

In the above embodiments, the yaw vibration correction signal is a single rectangular pulse, but it may be a signal with other waveforms such as a triangular wave signal or a trapezoidal wave signal, and as in each of the above embodiments, By correcting the waveform such as the amplitude for each normal reproduction state, horizontal shaking of the reproduced image can be prevented.

By the way, (1) Considering the response characteristics of the head cylinder speed control system of the air recording and reproducing device, the relative head-tape speed in the still image playback state and the normal playback state when the tension of the magnetic tape is constant is Theoretically, the optimal oscillation correction signal for fluctuations is generally determined by the signal f in FIG.
4a of the waveform shown as 0. This optimal rolling correction signal f. has a very complicated waveform, but even if it is approximated by a mantissa [multiplex], it is possible to obtain an equivalent roll correction effect for one reproduced image.

As yet another embodiment of the magnetic recording/reproducing apparatus according to the present invention, an optimum rolling correction signal f is provided. A description will be given of the roll correction No. 16 f1 shown in FIG. 9, which is approximated by a total of four nozzles.
It has the same configuration as H1, but the roll correction signal obtained from the correction signal generation circuit 15 has the waveform shown in FIG.

Such roll correction signal f1 is, for example, ;F in FIG.
+ii is generated by the positive signal generation circuit 15, and in the first normal playback state, the rotational speed of the head cylinder motor 7 is 1■
Used for control. However, such roll correction signal f,
Although it is possible to prevent horizontal shaking of the reproduced image due to fluctuations in the relative speed of the head and tape, it is not possible to correct uneven rotation of the rotating head due to fluctuations in the tape load torque, and horizontal vibration still occurs in the reproduced image. is born.

Therefore, based on the detection signal i (Fig. 9) from the amplifier 19 (Fig. 7) when the roll 111 positive number d f, As shown in the 91st line of the signal f2, the amplitude of each pulse forming the previous normal reproduction state of lateral vibration + Hi-stop No. 6 1 is obtained by varying the amplitude. That is,
Among the four pulses forming the roll *+II positive polarization f, the amplitude of the pulse that has a large influence on the periodic fluctuation of the horizontal synchronization signal is taken into account to determine the roll correction signal f in the next constant state. , is good.

Similarly, for each normal playback state, the detection signal obtained in the previous normal playback state is used to determine the H "constant pulse" among the four nozzles that form the roll correction signal during the previous normal playback. By changing the amplitude of A4, a corrected rolling motion correction signal is obtained. In this way, the rolling motion of the reproduced image during noiseless slow motion playback is significantly reduced.

In each of the above embodiments, a case has been described in which the periodic fluctuation of the reproduced horizontal synchronization signal is detected and the roll correction signal is corrected. However, the present invention is not limited to this, and for example, An AFC circuit that converts the frequency of a low-frequency converted carrier color signal reproduced from a magnetic tape and returns it to a carrier color signal of a regular frequency, and generates and outputs the signal based on a horizontal synchronizing signal, etc. Other means may also be a periodic variation detector.

〔Effect of the invention〕

As explained above, the invention does not measure the fluctuation of the head/tape relative speed when transitioning from the still image playback state to the normal playback state, but it measures the 5-turn head rotational unevenness caused by the fluctuation of the tape load torque. Therefore, the magnetic During slow-motion playback due to intermittent tape drive, the horizontal shaking of the playback image edge at step 1 is reduced to Ij4, and it is possible to provide an excellent performance recording and playback device that eliminates the drawbacks of the above-mentioned prior art. .

[Brief explanation of drawings]

FIG. 1 is a graph showing changes in the running speed of the magnetic tape during noiseless slow motion playback. aλ2131 is a vector diagram showing the relationship between head and tape relative speeds in the still image reproduction state and the normal No. 1 raw state. FIG. 3 is a block diagram showing an example of the magnetic recording/reproducing device from iE, FIG. 4 is a timing chart for explaining the operation of FIG. 3, and FIG. 5 is a side view of the magnetic recording/reproducing device according to the present invention. FIG. 6 is a waveform diagram of the rolling correction signal corresponding to the periodic fluctuation of the horizontal synchronizing signal (according to the period variation of the horizontal synchronization signal in the embodiment of FIG. 5), and FIG. A block diagram showing another embodiment of the playback device, FIG.
FIG. 9 is a waveform diagram showing the relationship between the oscillation correction signal and the frequency M fluctuation of the horizontal synchronization signal in the embodiment shown in FIG.
FIG. 7 is a waveform diagram showing a relationship between a specific example of the n-shohoku signal and the periodic fluctuation of its horizontal synchronization signal. 2...System ff1ll Go'? 5,
7...Head cylinder motor, 8...
・Capstan motor, 15... Correction signal generation circuit, 13... Suction signal processing circuit, 14...
...Periodic fluctuation detection circuit. Fig. 1 Fig. 2 Fig. 3 Downward Fig. 4 Fig. I Mouth 5 Fig. ω80 Diagram 9

Claims (1)

[Claims] In a magnetic recording curing device in which a magnetic tape with tracks formed in a diagonal direction is made to run intermittently, and the magnetic tape is read and scanned by a rotary head both when the magnetic tape is stopped and when it is running to perform slow motion playback. , a first means for generating a correction signal for changing the rotational speed of the head cylinder motor during running of the Ia tape, a means for the nest 2 having a memory function, and detecting periodic fluctuations of the reproduced horizontal synchronizing signal. A detection signal representing the periodic fluctuation is supplied from the third means to the base on which the magnetic tape runs, and the second means detects the following based on the detection signal. A magnetic recording/reproducing apparatus characterized in that the waveform of the correction signal by the first means is changed when the magnetic tape is running.