KR900005287B1 - Magnetic record regenerative apparatus - Google Patents

Abstract

The appts. includes a switching arrangement which is adapted to switch a reproduction speed into a speed faster than the normal reproduction speed and of two times speed or lower. The appts. also includes a reproduction time compressor (13) for sound signals and a switching device (7) which is adapted to perform the switching operation for sound signals effected by the reproduction time compressor and the output of the sounds. The reproduction is adapted to be performed by the head which is different in azimuth angle during the normal reproduction operation from the double azimuth heads.

Description

Magnetic recording and playback device

1 is a circuit diagram showing a schematic structure of one embodiment of the present invention.

2 to 8 are signal waveform diagrams explaining the function of each part of the circuit structure of FIG.

9 is a circuit diagram showing details of the capstan servo circuit of the circuit structure of FIG.

10 is a plan view of the rotating head of FIG.

11 is a diagram showing a head track of magnetic tape by a rotating head.

12 is a control block diagram for controlling an image signal from the rotating head of FIG.

FIG. 13 is a time difference art showing the operation of the control block diagram of FIG.

* Explanation of symbols for main parts of the drawings

1 capstan servo circuit 2 control head

3: capstan 5: tape

6: rotating head 7: head switch circuit

8: video reproduction circuit 9: audible head

10 audible amplifier 11 sound switch

12: video search switch 13: playback time reduction means

14: chopper circuit 15: oscillation circuit

21: amplifier 22: frequency divider

23: frequency discriminator 26: frequency divider

27: phase comparators 31, 32, 33: head amplifier

34: demodulation circuit 40: pulse selection circuit

The present invention relates to a magnetic recording and reproducing apparatus of a video tape recorder or the like, and more particularly to a magnetic recording and reproducing apparatus for reproducing a speech sound at a speed other than a normal reproduction speed.

There is a so-called video search function that makes the traveling speed of the magnetic tape faster than the normal playback speed of the playback of the video signal recorded on the video tape recorder or the like, thereby viewing the recorded video in a shorter time. .

When the tape speed is n times faster than the normal speed, the sound signal reproduced at the same time as the video signal becomes n times the frequency of the normal sound signal, or the speech becomes n times faster than the normal sound, making it very difficult to listen.

To solve this problem, a so-called variable language that converts the frequency of sound signals to a normal frequency and stores them from the memory by a clock at a speed faster than the normal playback speed to read them from the memory by a clock slower than a memory clock. There is a variable speech control (Vsc) method. However, during normal video search, the tape speed is about 10 times faster, so if the variable J is performed, the words are 10 times faster, thus making it very difficult to hear.

Therefore, an essential object of the present invention is to control the tape speed so that the variable sound is carried out during the video search operation and the sound which is reproduced is fast enough to be easy to hear. About two times faster (by actual measurement) is the limit of the tape speed for easy listening, and the tape speed needs to be controlled up to two times or less. In other words, the tape speed is required to be increased to a certain size in consideration of easy sound and search operation. Therefore, about 1.5 times faster is the optimal value.

The magnetic recording and reproducing apparatus includes image reproducing means, sound reproducing means, reproducing speed switching means, reproducing time reduction (VSC) means of sound signals, and sound signals executed by the VSC means to output them, and sounds not executed by the VSC means. And switching means for switching the signal. When the playback speed is switched by the playback speed switching means to two or less times faster than the normal playback speed (e.g., 1.5 times faster), the acoustic signal executed by the VSC means is switched by the switching means and output. Therefore, audible sound is output during the video search operation.

The magnetic recording and reproducing apparatus includes a tape conveying means for driving a magnetic tape, a speed detecting means for detecting a tape traveling speed, a phase detecting means for detecting a control signal recorded on the magnetic tape for phase control of the image reproducing means and the magnetic tape. And a control means for transmitting a given signal to the tape conveying means in accordance with the signal detected from the phase detecting means and the speed detecting means, wherein the control means detects the detected signal from the phase detecting means and the speed detecting means at a given value. Compensation means for compensating the signal is provided.

A rotating head having a head disposed diagonally of the rotating drum is a double azimuth head, switching means for selecting a regenerative output provided by each of the heads, and switch control means for driving the switching means in accordance with a given command is provided.

When the recorded magnetic tape is reproduced at a speed of 1.5 times the normal reproduction speed, the switch operation is performed as one of the double azimuth heads in the vertical blanking period in the switching means.

These and other objects and aspects of the present invention will become apparent from the following description taken in connection with the preferred embodiments thereof with reference to the attached drawings.

Before proceeding with the description of the present invention, it should be noted that the same parts are indicated by the same reference numerals through the accompanying drawings. 1 shows an embodiment of the present invention. The capstan motor 4 is controlled by the speed signal from the capstan 3 and the control signal from the control head 2 so that the capstan servo circuit 1 makes the tape 5 at a constant speed. The rotating head 6 reproduces the video track of the tape 5. The switching and outputting operation is performed at the command given by the head switch circuit 7. It is converted into a video signal by the video reproducing circuit 8 and output as a video. The audible head 9 reproduces the audible track of the tape 5 amplified by the audible amplifier 10.

As the sound switch 11 is connected to the a side during the normal regeneration operation, the output of the amplifier 10 is provided as sound through the sound switch 11.

In order to provide the video search method, a signal 1.5 times as speed is output as the operation of the video search switch 12 is switched.

The capstan servo circuit 1 is operated by a speed signal of 1.5 times, and the speed of the tape 5 becomes 1.5 times the normal reproduction speed.

The detailed description of the circuit 1 will be made later. The head switch circuit 7 also has its operation converted by a speed signal of 1.5 times, which will be described later in detail. The sound switch 11 is also switched to the b side by a signal 1.5 times faster. Thus, the output of the audible amplifier 10 is adapted to output the sound of the sound signal executed by the reproduction time reduction means 13.

The reproduction time shortening means 13 will be described later. If the standard reproducing waveform of the audible amplifier 10 is assumed to be the second degree during the normal regeneration, the waveform of 1.5 times the speed becomes the third degree. The Zipper circuit 14 has the waveform of FIG. 2 as an input and calculates the ratio of conduction to non-conductivity through the rectangular wave output (FIG. 6) of a certain time T (e.g., about 20 ms) of the oscillation circuit 15. Is cut by / T2. The oscillation circuit 15 is a circuit for generating a waveform of T1: (T1 + T2) = V1: V2 according to the speed signal from the capstan 3, where V1 is the normal speed and V2 is the speed of the search operation. to be. The chopper circuit 14 generates the input waveform of FIG. 3 by the output of such an oscillating circuit 15 such as the output waveform of FIG. 4 through the gate operation by the ratio of T1 / T2. That is, the waveform of FIG. 4 is cut into the waveform only during the period of T2 from the waveform of FIG. If the sawtooth waveform production circuit 16 includes a waveform circuit and an integrating circuit, one time produces a sawtooth waveform output (Fig. 7) excellent in the linearity of T through manipulation by the output of the oscillation circuit 15. do. Voltage inversely proportional to the voltage of the sawtooth waveform output by a time T in which the voltage frequency conversion circuit 17 is adapted to the sawtooth waveform output through manipulation with the output of the sawtooth waveform production circuit 16 (that is, It is directly proportional when having an inclined angle opposite to that of 7 degrees) and has a linear voltage-frequency characteristic causing a clock pulse (FIG. 8) in which the frequency is converted to gradually reduce the oscillation frequency. The output waveform of the chopper circuit 14 as the input voltage (fourth) so that the analog shift resist 18 gradually transfers the input voltage toward the output terminal every time clock pulse (Fig. 8) of the voltage-frequency conversion circuit 17. Is adapted to gradually transmit a voltage equivalent to the input voltage.

The analog shift register 18 is called a bucket relay and is composed of a MOS type IC and is connected to the capacitor capacity of the previous stage by the control of the FET with the clock pulse through the intermediate connection of the combination of the capacitors having the capacitor capacity. The stored input voltage is gradually transferred to the capacitor capacity of the later stage. The transmission time is determined by the frequency, that is, the width of the clock pulse. The closer it is to the end of the time period sent in the drawing, the longer it becomes. Therefore, the waveforms A 'and B' in the timing T1 of the output waveform of FIG. 4 within the one time period T of the output of the voltage-frequency conversion circuit 17 depend on the frequency of the clock pulse (A "). Extends to (B "). A standard speed recording waveform, i.e., a waveform extending to the fundamental frequency conforming to the standard speed reproduction waveform (FIG. 2), is provided at the output of the shift register 18 as shown in FIG. When the extended waveform becomes 1 / 1.5 of the number of waveforms per unit time with respect to the basic tone of FIG. 2, the call becomes fast as the reproduced sound. The waveform shaping circuit 20 removes noise from the output waveform of the shift register 18 to form a waveform without noise. The output of the waveform forming circuit 20 is connected as an input of the main amplifier of the tape recorder so that the reproduced sound from the loudspeaker is turned. According to the present invention configured as described above, the high speed reproducing waveform for appearing at the input of the chopper circuit is cut at a given time by the pulse of the oscillating circuit and becomes a clock pulse within a time synchronized with the oscillating frequency. The truncated waveform remaining in time is extended, so that the waveform of the frequency conformed to the standard speed reproduction waveform is restored. Thus, the reproduction waveform is reduced in the number of waveforms in unit time, and this phenomenon can be seen in the recording contents, that is, the sound, and the sound is heard as a quick call in the human ear. In this case, when the frequency is equal to the standard playback speed, pronounced pronunciation is not reduced and the recorded contents are sufficiently captured at a time short enough than the recording time. The tape speed switching means is as described below.

9 shows the capstan servo circuit 1 and its periphery of FIG. 1 in more detail. The signal amplified by the amplifier 21 of the speed control portion is input to the frequency divider 22. In normal regeneration, the frequency divider 22 outputs the same signal as they do in the amplifier 22, but when a signal of 1.5 times the speed is input, the frequency of the input signal is doubled so that the frequency is divided into three and then its output Perform the operation. The output signal of the frequency divider 22 is input to one of the input terminals of the additional amplifier 24 through the frequency discriminator 23. The frequency of the input signal to the frequency discriminator 23 is such that when the signal is divided at the frequency by the frequency divider 21, the signal outputs a given signal to make the capstan motor 4 which is 1.5 times different and the signal is divided into the frequency divider ( If it is not divided at the frequency by 21), it is discriminated to output the same input signal. In the phase control section, the output signal of the amplifier 25 is input to the frequency divider 26.

The output signal of the frequency divider 26 is the same as those from the amplifier 25 in normal regeneration, but the shape of the recording track of the magnetic tape 5 when a signal of 1.5 times speed is input to the frequency divider 26. The track information provided from the control head 2 is divided into three at the frequency of the control signal so as to retain the positional relationship between the reproduction heads. The output signal of the frequency divider 26 is input via the phase comparator 27 to the other of the terminals at the input of the additional amplifier.

In the above-described control block diagram, the frequency dividers 22, 26 and the frequency discriminator 23 output the input signals as they are in the normal reproduction as described above, so that the speed of the tape 5 is the normal speed. Controlled. The operation in reproduction at 1.5 times the speed will be described next. When the 1.5 times speed signal is input to the frequency divider 22 and the frequency divider 26, the frequency corresponding to the rotational speed from the frequency generator FG is converted into 2/3 by the frequency divider 22, and the signal The frequency is continuously input to the additional amplifier 24 so that the divided signal is distributed from the additional amplifier 24 to increase the rotational speed of the capstan mauve 4 by 3/2 (1.5) times. The magnetic tape 5 is adapted to be distributed and received by the speed control portion at a speed of 1.5 times the normal reproduction speed. Further, when the control signal divided into three at the frequency of the phase control portion is input to the phase comparator 27, the phase relationship between the playback head and the recording track pattern of the magnetic tape 5 is maintained at a speed of 1.5 times. Therefore, the phase relationship between the recording track pattern of the magnetic tape 5 and the track pattern of the reproduction head is maintained even when the reproducing speed of the magnetic tape 5 is 1.5 times faster, thus making reproduction at 1.5 times noise free. .

As described above, the traveling operation of the magnetic tape is applied to be controlled at the speed during the reproduction of 1.5 times the speed, and the positional relationship between the recording track pattern of the magnetic tape and the track of the reproduction head is applied to be executed even in phase control, and thus Allows noiseless playback to be performed even at playback speeds of 1.5 times. The head switch circuit will be described next.

In the present invention, a dual azimuth head is employed as a plurality of reproduction heads. One embodiment is described next with reference to the drawings.

10 shows a rotating head 6 used in one embodiment of the present invention, with another playing head L 'disposed through a given gap G in the vicinity of one playing head R. FIG. The playhead L 'is different in azimuth from the playhead R, and has the same azimuth as the playhead L on the diagonal.

The horizontal synchronization signal is H, and the size of the gap G between the reproduction heads R and L 'is assumed to be 1H or 2H. This structure is called a dual azimuth head. 11 shows the positional relationship between the reproduction head and the magnetic head when the magnetic tape recorded by the reproduction head 6 is reproduced at the speed of 1.5 times normal.

The playhead tracks TL ', TL, and TR are located on the magnetic tape 5 by the playheads L', L, and R, respectively. The reproduction operation is executed by using the reproduction head L 'instead of the reproduction head R in reproduction of the first frame. The recording track L 'having the same azimuth angle as the first field reproduction is reproduced by the reproduction head TL'. In the recording operation between adjacent recording tracks R1 and R2, the reproduction is not performed when the azimuth angle differs from the azimuth angle of the reproduction head L '.

As described previously, the magnetic tape 5, the recording track pattern, and the playhead track in the video tape recorder at the driving operation of the rotating head 6 and the reproduction at 1.5 times the speed are four fields as shown in FIG. Has a relationship with The reproduction is a pattern having four fields in one cycle. Is converted to Further, the positional relationship between the reproduction head and the recording track pattern, that is, the tracking information, is output by the control signal recorded on the magnetic tape 5 at the normal reproduction speed. Tracking control should be performed by a control signal divided into three at a reproduction of 1.5 times the speed.

12 shows a control block diagram for removing the above-described control. The already described playheads R, L ', L, and head amplifiers 31, 32, 33 are shown in the figure.

The control switch SW1 selects the output signal of the head amplifier 31 or 32, and the control switch SW2 selects the output signal of the head amplifier 33 or the output signal coming from the switch SW1.

The signal selected from the switches SW1 and SW2 is output as a given video signal through the demodulation circuit 34.

On the other hand, a head switch pulse for switching the playhead in the video tape recorder is configured through the rotation of the rotary head 6. Conventionally, pulses have been used to switch the playhead R or L of the rotating head 6, but in this embodiment for switching either the playhead L or the R or L '. Control switch SW2 is used as a control signal.

In addition, this head switch pulse is input through one of the input terminals of the exclusive logic circuit 35 of the two input terminals and is input through an integration circuit composed of the resistor 36 and the capacitor 37.

The pulses from the exclusive logic circuit 35 are input to both the rising and falling edges of the head switch pulses.

In addition, a signal output through the three frequency divisions of the control signal to be obtained during reproduction is set to flip-flop circuit FF1 (S) and flip-flop circuit through a differential circuit composed of resistor 39 and capacitor 38. It is input to each return terminal R of (FF2) to (FF4).

Accordingly, the flip-flop circuit FF1 is set by the rising edge of the control signal to return the flip-flop circuits FF2 to FF4. The reproduction signal at 1.5 times the speed, the head switch pulse and the signals of the output terminals Q of the respective flip-flop circuits FF1 to FF4 are input. The head selection pulse for controlling the control switch SW1 and the chromaticity rotation signal for controlling the demodulation circuit 34 are output from the pulse selection output circuit 40. The control operation for reproduction at 1.5 times the speed will be described next according to the time difference art in FIG.

The chromaticity rotation signal and the head selection pulse which are used in the chromatic interference elimination process by the local pass conversion color signal demodulation circuit are in accordance with the signals of the output terminals Q of the flip-flop circuits FF1 to FF4. These signals are output by a predetermined command so that the output signal of video reproduction becomes maximum when a reproduction signal of 1.5 times speed is input.

Now flip-flop circuit FF1 is set at the output " high " at the pulse rise of the control signal divided by 3 at the frequency of the first field time and flip-flop circuits FF2 to FF4 are output " low " (L) ". The field then becomes the second one.

When the head switch pulse falls, a pulse is input to the terminal CK of each flip-flop circuit FFl to FF24 as a clock signal, so that the flip-flop circuit FF2 outputs "high" and the flip-flop circuit FFI , (FF3) and (FF4) output "low". The flip-flop circuit which outputs "high" produces a circle of FF1-> FF2-> FF3-> FF1 by the clock signal of both edges of a head switch pulse as a result.

One cycle in four fields is provided by this description and the head selection pulse is " high " only in the first field by the pulse selection circuit 40.

The switch SW1 is switched to the b side, and the signal from the playhead L 'is selected. The head selection pulse becomes " low " in the other second to fourth fields, and the switch SW1 is rotated to the a side so that the signal from the reproduction head R is selected.

The switch SW2 is controlled according to the head switch pulse. At " high ", the switch SW2 is switched to the c side, that is, the signal from the switch SW1 is selected.

At "low", the signal from the d side, i.e., the playhead L, is selected. Thus, for example, as shown in FIG. 2, the playhead of the first field (L '), the playhead of the second field (L), the playhead of the third field, and the fourth field ( The playhead of L) is selected, and as a result, that one period is repeated.

A 1.5x video playback signal without noise is output in this way. Further, the chromaticity rotation signal is supplied to the demodulation circuit 34 so that normal color reproduction is also executed.

Then, when the playhead switching operation is executed during the vertical erasing cycle, the playhead-free playback screen appears through the playhead switch operation.

During normal regeneration, the head select pulse is " low " when the switch SW1 is on the a side, thereby selecting the regeneration head R. The switch SW2 is on the c side when the head switch pulse is "high".

That is, the signal from the playhead is selected. When the headswitch pulse is "low" it is on the d side. In other words, the signal from the playhead L is selected.

In addition, a head switch pulse input to the pulse selection circuit 40 is used as a so-called chromaticity rotation signal.

The above has been explained by the so-called dual azimuth three heads of the dual azimuth heads R and L 'and the normal head 1. When the guard band is caused in the recording track pattern of 1.5 times speed reproduction, noiseless reproduction of 1.5 times speed may be performed by the double azimuth angle head using the dual azimuth head.

As described above, the reproduction has one head of the rotating head of two normal heads output as the dual azimuth head, during a given frame reproduction of 1.5 times the speed reproduction and during the normal reproduction operation from the dual azimuth head, It is adapted for execution by other heads that differ in azimuth. Thus, noise caused by the reproduction of adjacent tracks is raised.

As is apparent from the above description, the outputting operation according to the apparatus of the present invention is performed to make it easy to hear the call sound when the video search operation is performed through the listening of the call sound of the VTR or the like.

Although the present invention has been fully described by way of example only with reference to the accompanying drawings, it should be noted that various changes and modifications will appear to those trained in the art. Therefore, unless such changes and modifications fall within the scope of the present invention, they should be construed as being included therein.

Claims (5)

A capstan servo circuit 1 adapted to switch the playback speed at a speed two times or less than the normal playback speed, and a playback time shortening means 13 for the sound signal, and to output a speech sound, and also a playback time. And a head switch circuit (7) adapted to carry out a switching operation for an acoustic signal executed by the shortening means (13). 2. A magnetic recording and reproducing apparatus according to claim 1, wherein the capstan servo circuit (1) is adapted to switch the reproduction speed at a speed 1.5 times the normal reproduction speed. 3. The generator according to claim 2, wherein the capstan servo circuit (1) having a capstan motor (4) for driving the magnetic tape and the image reproducing means for reproducing the recorded video signal of the magnetic tape and the frequency generator for detecting the tape traveling speed (3) (F4), a control head 2, an amplifier 25, a frequency divider 26, and a phase comparator 27 for detecting a control signal recorded on the magnetic tape to control the phase of the image reproducing means and the magnetic tape; The capstan servo circuit 1 and the capstan servo circuit 1 for transmitting the signals given to the capstan 3 and the capstan motor 4 according to the detection signal from the frequency generator FG have a normal reproduction speed. And a calibration means for calibrating the detection signal from the control head (2) and the detection signal from the frequency generator (FG) to a given value in a reproducing operation of 1.5 times as fast as. 4. The image reproducing means according to claim 3, wherein the image reproducing means comprises a rotating head (6) having a head arranged at a diagonal of the rotating drum as a dual azimuth head, and a head switch circuit for selecting a reproducing output caused through each of the heads. 7) and a head switch circuit having a pulse selection circuit 40 for driving the pulse selection circuit 40 in accordance with a given command, whereby the switch operation reproduces the recording magnetic tape at a speed 1.5 times the normal reproduction speed. The reproducing apparatus executed by one of the dual azimuth heads in the vertical blanking period according to (7). And a reproducing speed for reproducing the sound signal recorded at high speed through the reproducing time reduction means (13) is adapted to be converted to a speed which is smaller than twice the normal recording speed but larger.

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