JPS62166673A - Slow-motion reproducing device - Google Patents

Abstract

PURPOSE:To facilitate running control by inputting output of a frequency multiplying means and comparing means and switching the third switching means in synchronism with a head switching signal so as to output the first or the second switching means of large envelope as a slow-motion reproduction signal. CONSTITUTION:At the time of slow-motion reproduction, a controlling signal inputted to an input terminal 31 becomes H, and a switch 30 is switched to (a) side, and switches 7, 9 are changed synchronously to (a) side and (b) side by a head switching signal 8. An envelope read out by magnetic heads 1, 3 and amplified by an amplifier 11 is detected and inputted to the positive terminal of a comparator 27. On the other hand, an envelope read out by magnetic heads 2, 4 and amplified by an amplifier 10 is detected and inputted to the negative terminal of the comparator 27, when the former is larger, a signal H is outputted. The head switching signal 8 is inputted and inversely inputted to T-type flip-flop 14, 17 and a 2-multiplied signal is outputted from an OR circuit 20. A switch 12 is switched in synchronism with the head switching signal 8 immediately after the reproduction output is compared through D-type flip-flops 28, 29, and reproduced signals of large envelope are outputted from a terminal 13.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a slow motion reproducing device for a magnetic recording and reproducing device capable of slow motion reproduction.

(B) Conventional technology In general, in order to perform noiseless slow-motion playback in a video tape recorder as a magnetic recording/playback device, two magnetic heads with different azimuth angles and wider than the recording track width are mounted on a rotating cylinder. 18
The two magnetic heads alternately scan the recording tracks of the magnetic tape, which are arranged at an angle of 0° and run at a speed slower than normal reproduction JfL.

Here, for example, Japanese Patent Laid-Open No. 75387/1987 has proposed a technique for performing slow motion playback. To briefly explain this technique, a first magnetic head consisting of a first and a second magnetic head having different azimuth angles is used. A pair of magnetic heads, a second magnetic head pair consisting of a third magnetic head having the same azimuth angle as the first magnetic head, and a fourth magnetic head having the same azimuth angle as the second magnetic head are each mounted on a cylinder. The first and fourth magnetic heads and the second and third magnetic heads are arranged at an angle of 180° to each other, and the first and fourth magnetic heads are placed in close proximity to each other. By selecting the second pair of magnetic heads one after another, a slow motion reproduction signal is obtained, that is, slow motion reproduction is executed.

(c) Problems to be Solved by the Invention However, in the above case, in order to intermittently advance the magnetic tape one track pitch at a time during slow motion playback, tape advance must be started at the timing of the signal obtained from the head switching signal, and at the same time playback must be performed. It is necessary to complete the tape feeding at the timing of the signal obtained from the control signal, and the tape feeding amount during this period must be one track pitch, which makes the control of the capstan motor for tape feeding complicated. In addition, since intermittent feed is a repetition of still and frame feed, the relative speed between the magnetic head and the magnetic tape changes, which causes horizontal fluctuations on the monitor screen. The rotational speed of the cylinder also had to be controlled depending on the speed.

(d) Means for Solving the Problems The present invention has been made to solve the above problems, and provides a first magnetic head pair consisting of first and second magnetic heads having mutually different azimuth angles. and a second magnetic head pair consisting of a third magnetic head having the same azimuth angle as the first magnetic head, and a fourth magnetic head having the same azimuth angle as the second magnetic head, respectively, in a cylinder. 1
In a magnetic recording/reproducing apparatus in which the first and fourth magnetic heads and the second and third magnetic heads are arranged at an angle of 80 degrees and are brought close to each other, a head switching signal is input, and the first and third magnetic heads are arranged at an angle of 80 degrees. The reproduction output by the magnetic head, the second
and first and second switch means for respectively switching reproduction outputs of the fourth magnetic head; third switch means for switching outputs of the first and second switch means; and a frequency for multiplying the head switching signal. a multiplying means, a comparison means for comparing the envelopes of the outputs of the first and second switch means, the outputs of the frequency multiplier and the comparison means being inputted, and the output of the first or second switch means having a larger envelope; The slow motion reproducing apparatus includes a control means that outputs a control signal for switching the third switch means in synchronization with the head switching signal so as to output the slow motion reproduction signal.

(*) Effect: According to the slow motion playback device of the present invention, the first and second switching means switch the first and second switches.
The reproduction output by the magnetic head of 1.2.3.4 is switched by the third switch means into which a control signal from the control means is input, and the normal reproduction speed is determined by the reproduction output of all the magnetic heads of 1.2.3.4 at this time. Noiseless slow motion playback can be performed even at the following constant speeds.

(f) Example The details of the present invention will be specifically explained with reference to the illustrated embodiments.

FIG. 1 is a circuit diagram showing an embodiment of the slow-motion playback device of the present invention, FIG. 2 is a timing cheat showing waveforms of each part of FIG. 1, and FIG. FIG. 4 is a plan view showing the arrangement of usable magnetic heads, and shows a case where a magnetic tape is played back in slow motion at a constant speed slower than the normal playback speed using two magnetic heads of the present invention, one of which has the same azimuth angle. FIG. 5 is a diagram showing the head trajectory in thick lines when slow motion reproduction is performed in the same manner as in FIG. Here, FIGS. 4 and 5 show recording tracks arranged repeatedly, where one scale on the horizontal axis indicates the time of one field and the switching timing of the magnetic head, and one scale on the vertical axis indicates one field. It shows the distance the magnetic tape travels during the lead time.

To explain the figure numbers and configurations of Figures 1 and 3,
(1) and (2) are first and second magnetic heads having different azimuth angles, (3) is a third magnetic head having the same azimuth angle as the magnetic head (1), and (4) is the magnetic head. A fourth magnetic head having the same azimuth angle as (2), wherein a first magnetic head pair is configured from the magnetic head (1>(2)) and the magnetic head pair (3) is configured from the magnetic head pair (2).
)(4) constitutes the second magnetic head pair, and (
5), the magnetic heads (1) and (2) are arranged at an angle of 180°, and the magnetic heads (3) and (4) are arranged at an angle of 180°.
The magnetic heads (1) and (4) are arranged at an angle of
a cylinder in which the magnetic heads (2) and (3) are arranged in close proximity to each other; (6) is a magnetic tape; (7)
The head switching signal shown in FIG. 2 (e) is inputted via the input terminal (8), and the reproduction output read from the magnetic tape (6) is switched by the magnetic heads (2) and (4). A first switch (9) receives the head switching signal, and a second switch (10) switches the reproduction output read from the magnetic tape (6) by the magnetic heads (1) and (3). )(11) are the switches (7) and (9), respectively.
) an amplifier that amplifies the output; (12) is the amplifier (10) that amplifies the output;
) (11) A third switch that switches the output and outputs it from the output terminal (13), (14) has a resistor (15) connected between its Q (output) terminal and R (reset) terminal, and also connects the R terminal. A T-type flip-flop has a capacitor 16) connected between it and ground, and the head switching signal can be input to its T (trigger) terminal, and a resistor (18) is connected between its Q terminal and reset terminal (17). Along with R
A T-type flip-flop has a capacitor (19) connected between the terminal and ground, and the head switching signal is invertedly inputted to the T-terminal of the T-type flip-flop, and (20) is the Q-terminal output of the T-type flip-flops (14) and (17). is an OR circuit into which is inputted, and a frequency multiplication means is constructed from the T-type flip-flops (14) (17) and the OR circuit (20), and (
21) is a diode whose anode is connected to the output side of the amplifier (10), (22) and (23) are a resistor and a capacitor each connected between the cathode of the diode (21) and the ground, and (24) is a diode whose anode is connected to the output side of the amplifier (10). The amplifier (11)
A diode whose anode is connected to the output side of (25)
(26) is a resistor and a capacitor connected between the cathode of the diode (24) and the ground, and (27) is a resistor and a capacitor connected between the cathode of the diode (24) and the ground, and (27) the output of the diode (21) is input to its - (minus) terminal, and The output is inputted to its + (plus) terminal, and the comparator (28) serves as a comparison means for comparing the power of both people, and the output of the comparator (27) is inputted to its D (data) terminal, and its C( The D-type flip-flop (29) has the output of the OR circuit (20) as an inverted input to its D-terminal (clock) terminal, and the Q-terminal output of the above-mentioned flip-flop (28) is input to its D-terminal, and the It is a D-type flip-flop to which the output of the OR circuit (20) can be input, and the control means is constituted by the above-mentioned flip-flops (28) and (29), and (30) has one switching terminal to which the head switching signal is input. As soon as the input is completed, the other switching terminal of the above-mentioned flip-flop (29) is turned on. A switch to which a Q (inverted output) terminal output is input, which is switched by a control signal for slow motion playback inputted to an input terminal (31), and which switches the switch (12) by a signal from the switched side. be.

The present invention will be explained in detail below. When performing normal playback for the first time, the control signal input to the input terminal (31) becomes low level (hereinafter referred to as "L") and the switch (30
) is switched to side b, and switches (7), (9), and (12) are switched to side a (hereinafter r
It is switched synchronously to the high level (high level indicated as H) and b ('L J) side. That is, switches (7) (9) (
12) is switched to the a side, the reproduction signal read out by the magnetic helad (2) scanning the recording track on the magnetic tape (6) running at a constant speed at a normal speed is transmitted to the amplifier ( 10) from the output terminal (13),
Furthermore, when the switches (7), (9), and (12) are switched to the b side, the reproduction signal read by the magnetic head (1) scanning the recording track on the magnetic tape (6) is transmitted to the amplifier ( 11) from the output terminal (13). In other words, the reproduced signals read by the magnetic heads (1) and (2) are transmitted to switches a and b of switches (7), (9), and (12).
By switching to the side, the output terminals (13>) alternately output, and normal playback is then executed.

Next, when performing slow motion playback (175x slow motion playback in this example), input terminal (3
The control signal input to 1) becomes rH, and the switch (30) is switched to the a side, and the head switching signal shown in FIG. 2 (e) causes the switches (7) and (9) to switch to a and b It can be switched synchronously with the side. Immediate switch (7) (9
) is switched to the a side, the magnetic heads (2) and (3) with different azimuth angles scan the recording tracks on the magnetic tape (6) running at a constant speed of 175 times, and the data is read out. The playback signal is sent to the amplifier (10) (11), respectively.
It can be amplified by . Also, when the switches (7) and (9) are switched to the b side, the magnetic heads (4) and (1) with different azimuth angles scan the recording tracks on the magnetic tape (6) to read out the playback tracks. The signals are each input to an amplifier (1
0) (11). Here, FIGS. 4 and 5 respectively show magnetic heads (1) and (3) with the same azimuth angle.
(2) Shows head trajectories according to (4). Furthermore, the diagonal lines in each head trajectory indicate the magnetic head (1 bar 3), (2) < 4
), and FIGS. 2(a) and 2(b) show envelopes obtained by amplifying each reproduced signal by amplifiers (11) and (10).

The magnetic heads (1) and (3) read out the information, and the amplifier (11
), the envelope shown in Figure 2 (a) is amplified by a diode (24), a resistor (25), and a capacitor (26).
) as shown by the solid line in FIG.
) (4) and amplified by the amplifier (10), the envelope shown in Figure 2 (b) is read out by the diode (21
), the second by resistor (22) and capacitor (23)
The signal is detected as shown by the broken line in Figure (d) and input to one terminal of the comparator (27). From this, both are compared, and only when the detection output in Figure 2 (A) is larger than the detection output in Figure 2 (B), the comparator (27) outputs the output as shown in Figure 2 (G). A signal of rH is output.

On the other hand, the head switching signal is transmitted through a T-type flip-flop (14).
(17) is also input and inverted to each T terminal. Here, in the case of a T-type flip-flop (14), the resistor (15)
and “L” or r H determined by the capacitor (16)
The C terminal output is reset by the time constant of 172 cycles of the head switching signal of , and the T-type flip-flop (1
7), the resistor (18) and capacitor (19)
The C terminal output can be reset by the time constant of 172 cycles of the L or rH head switching signal, which is determined by From the OR circuit (20) to Figure 2 (
As shown in ), a signal obtained by multiplying the head switching signal by 2 is output.

The output of the comparator (27) obtained above is input to the D terminal of the D-type flip-flop (28), and
0) The output will be inverted input to the C terminal, and the C
The signal shown in FIG. 2 (H) is output from the terminal. In other words, the signal in FIG. 2 (H) rises and falls between the rise and fall of the head switching signal. In other words, the magnetic heads (1), (3), (2) and (4) are connected to the magnetic tape. (6)
You can compare the playback output when scanning approximately the center of the recording track above.

And the C terminal output of the D type flip-flop (28) is D
The signal can be input to the D terminal of the type flip-flop (29), and the output of the OR circuit (20) can also be input to the C terminal, and the signal shown in FIG. 2 is output from the ζ terminal. That is, the signal in FIG. 2(S) rises and falls in synchronization with the first rise and fall of the head switching signal immediately after the rise and fall of the signal in FIG. 2(H),
In other words, when the reproduction outputs of the magnetic heads (1), (3), and (2) and (4) are compared, the time t1. The switch (12) is quickly switched every t2. From this, as shown in Figure 2 (C), by switching the switch (12), the reproduction signal of either one of the larger envelopes (Figure 2 (A)) is output from the output terminal (13), resulting in a noiseless is played in slow motion.

In this embodiment, the slow motion playback speed is set to 175 times the normal playback speed, but the slow motion playback speed is not limited to this, and slow motion playback can also be performed at a constant speed that is lower than the normal playback speed. It goes without saying that there is.

(g) Effects of the Invention According to the slow-motion playback device of the present invention, slow-motion playback is possible by running the magnetic medium at a constant speed below the normal playback speed, making it easy to control the running of the magnetic medium. Furthermore, since no horizontal fluctuation occurs on the monitor screen, there are advantages such as no need to control the rotational speed of the cylinder in accordance with the traveling speed of the magnetic medium.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing one embodiment of the present invention, and Fig. 2 is a circuit diagram showing an embodiment of the present invention.
FIG. 13 is a plan view showing the arrangement of the magnetic head according to the present invention, and FIGS. 4 and 5 are diagrams showing the head trajectory during slow motion reproduction according to the present invention. (1) (2) (3) (4)...Magnetic head, (5)
...Cylinder, (6) ...Magnetic tape, (7
)(9)(12)...Switch, (14)(17
)...T-type flip-flop, (15)(18)
...Resistance, (16) (19)...Capacitor,
(20)...OR circuit, (27)...comparator,
(28) (29)...D type flip-flop. Applicant: Sanyo Electric Co., Ltd. and one other representative: Shizuo Sano, patent attorney. t 3rd figure 4th figure Jikai- 5th figure vj@- Yamiichi

Claims (1)

[Claims] (1) A first magnetic head pair consisting of first and second magnetic heads having different azimuth angles, a third magnetic head having the same azimuth angle as the first magnetic head, and the second magnetic head. and a second magnetic head pair consisting of a fourth magnetic head having the same azimuth angle are arranged in the cylinder at an angle of 180°, and the first and fourth magnetic heads, the second and third magnetic heads In a magnetic recording and reproducing apparatus that performs recording and reproducing on a magnetic medium by bringing heads close to each other, a head switching signal is input, and the reproduction output from the first and third magnetic heads and the reproduction output from the second and fourth magnetic heads are input. first and second switch means for respectively switching reproduction outputs; third switch means for switching the outputs of the first and second switch means; frequency multiplication means for multiplying the head switching signal; A comparison means for comparing the envelope of the output of the second switch means, and the outputs of the frequency multiplication means and the comparison means are input, and the output of the first or second switch means having a large envelope is outputted as a slow motion reproduction signal. 1. A slow motion reproducing apparatus comprising: a control means that outputs a control signal for switching the third switch means in synchronization with the head switching signal.