JPS58203601A - Mode switching system during recording pause - Google Patents

Abstract

PURPOSE:To prevent the noises generated from reproduction of an unrecorded part and furthermore to ensure the reproduction with monitor for a video signal to be recorded by setting an E-E mode during an overrun period. CONSTITUTION:The demodulated video signal is reproduced with monitor through a buffer amplifier 13 and an output terminal 14. A recording mode is equal to an E-E mode in which the input video signal of an input terminal 1 of a recording system emerges as it is at the terminal 14. A microcomputer 9 switches previously a switch circuit 11 to a terminal (b) from a terminal (a) with a delay equivalent to a period a little longer than an overrun period. At the same time, the computer 9 produces a switching signal to switch a switch circuit 5 to the side of a terminal P simultaneously with or before a switch to the terminal (b). Therefore a recording action is inhibited during the overrun period, and at the same time the E-E mode is kept as it is. Thus the video signal fed to the terminal 1 is delivered directly to the terminal 14.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mode switching method during recording pause.
When a tape-shaped recording medium (hereinafter referred to as "tape") slightly overruns due to the operation of the recording pause switch of a recording/reproducing device, it is caused to travel in the opposite direction for a certain period of time, and then stops, at least from the time when the recording pause switch is operated. It is an object of the present invention to provide a mode switching method that can reduce the occurrence of noise on a playback screen by switching to the E-E mode during a tape overrun period.

Conventionally, in order to record continuous shots with less screen disturbance, VTRs have had to operate the recording pause switch while recording video signals on a tape running in a fixed direction (this is referred to as the forward direction). Then, the tape is made to run in the opposite direction, and is stopped after a certain period of time (for example, about 1 second) has elapsed. For example, the pinch roller is in a standby state (recording enter the pause state). After that, when a play switch is operated, for example, when the next video signal to be recorded is received, the above-mentioned recording pause state is canceled, the tape is made to run in the forward direction again, and the above-mentioned period of rewinding is completed. The time period is also slightly smaller (e.g. 0,
(about 9 seconds), the tape run is controlled based on the playback signal of the control track recorded on the tape immediately before the above-mentioned recording pause switch operation, and after playback is performed, the mode is automatically switched to the recording mode. , recording of the video signal to be recorded next is started. Note that during the period from the standby state to the resumption of recording, the VTR is switched to the E-E mode.

In other words, the playback period after the recording pause state is released takes longer than the time it takes for the servo circuit, to which the playback signal from the control track is supplied, to reach a stable state of operation, and recording resumes when the servo operation is stable. When it happens, I get K. Furthermore, since the phase of the control pulse recorded on the control track near the recording seam is maintained at a constant cycle, it is possible to prevent screen disturbances at the recording seam due to unstable servo operation during playback. .

However, in the above-mentioned conventional VTR, the tape is not rewound immediately after the recording pause switch is operated, but is actually rewound in the J plane direction for about 0.2 to 0.5 seconds due to the inertia of the capstan. However, during the period from the time when the recording pause switch was operated until the standby state was reached, the rewind mode was switched to the playback mode, so during the above-mentioned overrun period. This method had the disadvantage that unrecorded portions of the tape were played back, and noise was generated on the playback screen.

The present invention eliminates the above-mentioned drawbacks, and an embodiment thereof will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the method of the present invention, and FIG.
The figure is a diagram schematically showing the operation of the system of the present invention. In FIG. 1, in the recording mode, the video signal input to the input terminal 1 is supplied to the FM modulator 3 through the automatic gain control circuit (AGC circuit) 2, where it is FM modulated and then sent to the recording amplifier 4. The signal is then amplified to the background level and applied to the terminal R of the switch circuit 5. The switch circuit 5 is connected to a terminal R in the recording mode in response to an output switching signal from a microcomputer 9, which will be described later, and supplies the FM signal extracted from the recording amplifier 4 to the rotary head 6. From this point K, an FM signal is recorded by the rotary head 6 onto the magnetic tape 7 which is being run in the forward direction.

On the other hand, in this recording mode, the switch circuit 11 is switched to the terminal a by the output switching signal of the microcomputer 9.
The FM demodulator 12 is connected to the FM modulator 3 to supply the FM signal from the FM modulator 3 to the FM demodulator 12. For this reason, FMu
A demodulated video signal that is the same as the video signal to be recorded that has entered the input terminal 1 is taken out from the I modulator 12, and this demodulated video signal is passed through a buffer amplifier 13 and sent to a monitor television receiver (not shown) from the output terminal 14. ) and is monitored and played back here. Therefore, the recording mode described above is also an E-E mode in which the input video signal at the input terminal 1 of the recording system appears as is at the output terminal 14 of the reproduction system.

Next, when the VTR user operates a recording pause switch (not shown) at a timing desired by Pfr, a pause command signal is supplied from the input terminal 8 to the microcomputer 9.

As a result, the microcomputer 9 supplies a recording mute signal to the recording amplifier 4 to turn the recording amplifier 4 into an output signal cutoff state, and at the same time rotates the supply side reel motor (not shown) in the reverse direction in the rewinding direction. The capstan motor (not shown) is also rotated in the opposite direction.

However, the magnetic tape 7 does not stop immediately due to the inertia of the capstan motor, for example, after 0.2 seconds to 0.5 seconds of machine speed. After traveling in one direction, the vehicle starts traveling in the opposite direction.

The microcomputer 9 delays the switching circuit 1 in advance by a period slightly longer than the above-mentioned overrun running period.
1 from terminal a to terminal b, and at the same time as the switching connection to this terminal, the switch circuit 5 is connected before that.
A switching signal is generated to switch and connect the terminal P to the terminal P side. Therefore, at least during the above-mentioned overrun period.

Since the βα recording operation is stopped and the E-E mode continues, the video 18 input to the input terminal 1
The signal can be output to the output terminal 14 as is.

FIG. 2 is a diagram showing the transition of the above modes, where point A indicates the time point when the recording pause switch is operated, and the diagonally shaded area indicates the forward overrun running period which is set as E-E mode according to this embodiment. . Note that REC/(EE) indicates the recording mode and the EE mode.

Thereafter, when the magnetic tape starts to run in the opposite direction due to the reverse rotation control of the supply reel motor and the capstan motor, the switch circuit 5 switches to the terminal P as described above.
Since the switch circuit 11 is switch-connected to the terminal side, the rotary head 6Vi operates as a reproducing head, and the signal reproduced from it passes through the switch circuit 5, the regenerative amplifier 10, and the switch circuit 11, respectively. FM demodulator 1
2, where it is translated into FM@, and further outputted to the output terminal 14 via the buffer amplifier 13.

The microcomputer 9 rotates the supply reel motor and the capstan motor in reverse during the above-mentioned overrun running period and the tape running period of about 1 second, and then stops the rotation of the supply reel motor. At the same time, a signal is generated to stop the rotation of the capstan motor and the running of the magnetic tape 7 is stopped.
Almost at the same time as the motor rotation stop signal is sent, a switching signal is generated to switch the switch circuit 11 from terminal A to terminal A. Therefore, as shown by PB in Fig. 2, 1411
During the above-mentioned overrun running event and the tape running period in the reverse direction for about 1 second, after switching to the playback mode in which the video signal played by the rotary head 6 is output to the output terminal 14,
At the time of tape running in the pure land indicated by B in the figure, the switch circuit 1
By connecting to terminal a of 1, output terminal 14 is connected to input terminal 1.
The input video signal is taken out and switched to the beak E-E mode.

When the tape stops running, the pinch roller remains pressed against the capstan via, for example, the magnetic tape 7, and the VTR enters the above-mentioned standby state.

Thereafter, when the user operates the play switch when a video signal for continuous recording is received, the microcomputer 9 generates a signal to rotate the winding side motor and capstan motor in the forward direction. Then, the magnetic tape 7 starts running in the forward direction, and when about 0.9 seconds, which is the time required for the servo circuit to reach optically stable operation, has elapsed, the switch circuit 5 is switched from the terminal P side to the R side. The recording amplifier 4 is made operable by generating a switching signal to continue the recording amplifier 4 and stopping sending out the recording mute signal. Note that the switch circuit 11 is kept connected to the terminal a side. Therefore, as shown in Fig. 2, the VTR is in E-E mode during the period from time C when the play switch is operated until approximately 0.9 seconds have elapsed, and monitors and reproduces the video signal to be recorded. , after that, it will switch to the recording mode and the E-E mode.

However, during the period from the play switch operation point C to the start point of the recording mode shown in FIG.
It is similar to a conventional VTR that the control pulse recorded in the control track is reproduced and the servo operation is performed based on it.

Although the above embodiment has been described as being in the regeneration mode during the reverse direction driving period of the overrun event, the E-E mode may also be used during this period. In that case, the microcomputer 9 is used to set a time in advance that takes into account the overrun reciprocating period shown by the two parallel lines in Figure 2 from the time when the recording pause switch is operated, and when this time has passed, the switch is Possible methods include switching the circuit 5 to the terminal P side and simultaneously switching the switch circuit 11 to the terminal P side.

As described above, the mode switching method during recording pause according to the present invention switches the E-E mode at least during the forward overrun running period from the time when the recording pause switch is operated until the tape-shaped recording medium is rewound. The conventional recording and reproducing apparatus, which was in the reproducing mode even during the overrun period, eliminates the noise generated by reproducing the unrecorded portion during the overrun period. , it can be prevented from occurring by setting it to the E-E mode, and it also has the advantage of being able to monitor and reproduce the video signal that is about to be recorded.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the method of the present invention;
FIG. 2 is a diagram schematically explaining the operation of the system of the present invention. 1... Video signal input terminal, 4... Recording amplifier, 5°11... Switch circuit, 6... Rotating head, 7...
・Magnetic input terminal, 8... Pause command signal input terminal, 9.
...Microcomputer, 14...Video signal output terminal.

Claims (1)

[Claims] Recording/playback in which the tape-shaped recording medium on which recording has been previously performed is set in playback mode for a certain period of time and rewound by operating a recording pause switch, and then the running of the tape-shaped recording medium is stopped and switched to E-E mode. When the device is in a recording pause, the device maintains the E-E mode at least during a forward overrun running period from the time when the recording pause switch is operated until the tape-shaped recording medium is rewound, and then shifts to the playback mode. A mode switching method during a recording pause in which switching is a % characteristic.