JPS6238386Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a still image recording and reproducing device. A device that extracts and stores one scene of the video signal projected on the screen of a television receiver in a recording medium such as a magnetic disk sheet, and displays the recorded signal as a still image on the screen of the receiver. For example, it is known from Japanese Unexamined Patent Publication No. 51-49614, but in view of the application, a unit video signal is extracted, recorded, and reproduced by pressing a recording command button, and release of the button is detected. It was configured to access and wait for the next track. This has the advantage of being able to monitor the reproduced still image that has been sampled and recorded while the recording command button is pressed, but on the other hand, access control to the next track is performed when the button is released, so the pressing time is short. In the case of time, there is a drawback that track access is performed before the unit video signal is completely recorded on the recording medium. For example, as in the above-mentioned known example, after a recording command is input, the track to be recorded is erased in one field period immediately after that, the next one feed period is set as a blank period, and the next one feed period is used as a unit. If the format is such that a video signal is recorded, pressing for a time equivalent to a maximum of 4 feeds (up to 1 field blank may occur before the erasing operation), that is, approximately 66 milliseconds, is not ensured. Defects are recognized. In reality, it is extremely rare for one pressing operation to take less than the above time, but there is no guarantee that it will never happen, and this concern is due to the fact that one frame recording is necessary to improve the quality of recorded and reproduced images. This becomes even more difficult to ignore when the format is determined to allow playback. Moreover, when this device is used for medical purposes, such as for recording and storing ultrasound tomographic images, there are many occasions where it is used to issue recording commands one after another without checking the monitor images one after another. In some cases, the pressing time becomes shorter and the above drawbacks cannot be ignored. In order to solve this drawback, the present invention generates a constant pulse regardless of the length of the operation time when a recording command is received, and uses the pulse output to reliably control the recording gate until the recording of a unit video signal is completed. It is an object of the present invention to provide a magnetic recording/reproducing device which can be opened.

FIG. 1 shows a block diagram of an embodiment of the device of the present invention, in which a video signal containing, for example, an ultrasonic tomographic image is input to terminal 1, and the signal is sent to an AGC circuit for magnetic recording. It is processed appropriately by a preprocessing circuit 2 including a clamp circuit and a clip circuit, and is supplied to a magnetic head 7 through an FM modulation circuit 3, a one-frame gate circuit 4, a recording amplifier 5, and an R terminal of a first switch 6. , a unit video signal (one frame) is recorded on the track 9 of the recording medium 8 such as a magnetic sheet at the timing when the gate circuit is opened.
Record. At the same time, the output of the FM modulation circuit 3 is transmitted through the R terminal of the second switch 10 which is controlled in conjunction with the first switch, and the limiter circuit 12, FM demodulation circuit 13, and reproduction amplifier 14 that constitute the reproduction circuit 11. The image is converted into the original video signal and displayed on the screen of the monitor 15. On the other hand, when both the switches 6 and 10 are switched to the P terminal by a relay drive circuit 16 driven by a signal from a gate signal generation circuit (described later), the signal recorded on the track 9 is displayed on the screen of the monitor 15. will be displayed on the screen. M is a motor that controls the rotation of the recording medium, and this motor is automatically started after a short delay after the power is turned on by a power-on switch (not shown) to prevent noise from entering when the power is turned on. I try to avoid it.

Reference numeral 17 denotes a remote control operation section for issuing various command signals, and its front layout is as shown in FIG. Reference numeral 18 is a group of controls for externally attaching notes such as patient's medical record numbers to recorded contents. The numbers corresponding to the display of this group of operators are recorded together with the unit video signal to be recorded. 1
Reference numeral 9 denotes a group of operators for specifying tracks, which includes buttons 0 to 9 and G and C buttons, and the so-called numeric keypad is used to specify a track, and the G button is used to command its execution. The track numbers before and after the command are displayed from the track display window 20.
The C button is an error indicator 21 that lights up when more tracks than the allowable number of tracks are specified.
This is to cancel the above designation based on the following.
22 is a button to move forward by one track, 23 is a button to move backward by one track, 24, 25, and 26 are buttons for commanding monitoring, recording, and playback, respectively.
7 and 28 are a monitor and a reproduction status display, respectively.

Reference numeral 29 denotes a gate signal generation circuit that generates various gate signals, and this circuit generates signals based on the vertical synchronization signal separated from the video signal by the vertical synchronization separation circuit 30 and various command signals provided from the remote control operation section. It is becoming more and more likely to occur. FIG. 3 shows a part of this gate generating circuit, and its operation will be explained with reference to the time chart shown in FIG. 4. It is assumed that the magnetic head is located on track _T1 as shown in FIG. 5 and is in the monitor mode. At this time, when the recording command button 25 is pressed, the signal shown in Fig. 4a is triggered in the mono multivibrator 31, and _a pulse (Fig.
Derive. This is the pressing time τ of the recording command button.
This means that pulse output for 3 frames or more is always guaranteed regardless of the magnitude of ₂ . This pulse b is input to the clear terminal of the counter 32 to clear its contents, and is also applied to the other input terminal of the NAND gate 33, which is set at a high level when one input terminal 33a is in the monitor mode, and through it. The signal is input to the JK flip-flop 34, and a pulse as shown in FIG. 4C is derived as its output. And this output is one input terminal 35a
The vertical synchronizing signal d is input to 1/ by the T flip-flop 36.
The vertical synchronizing signal is supplied to the other input terminal 35b of the NAND gate 35 whose frequency is divided by 2, and is input to the counter 32 only during the high level period.
A 1/2 frequency divided output is supplied, and each bit output thereof is applied to a logic circuit 37, which outputs an erase gate signal and a recording gate signal as shown in FIG. 4e and f as its output. The recording gate signal then resets the JK flip-flop 34 at its trailing edge and is input to the mono multivibrator 38. At the rising timing of the terminal of the mono multivibrator 38, the output of the logic circuit 39 is inverted from high level to low level, and the relay drive circuit 16 is activated to switch the first and second switches 6, 10 from the R terminal to the P. Activate the relay 40 for switching to the terminal. Further, the Q terminal output (Fig. 4g) of the mono multivibrator 38 is further input to the mono multivibrator 41, and its output is applied to the logic circuit 39 to return it to its original state, that is, monitor mode. At the same time, a pulse motor 42 that drives the magnetic head 7 is
This signal is provided to the pulse motor drive circuit 43 as a trigger for moving in the forward direction by the amount of the track, that is, from track _T1 to _T2 in FIG. Incidentally, the metastable time of each of the mono-multivibrators 38 and 41 is appropriately determined in consideration of the necessary regeneration time. As mentioned above, when the recording command button is operated in the monitor mode, the erase current necessary for erasing is supplied from the circuit 44 to the erase head 7' by the erase gate signal (FIG. 4e) for the subsequent one frame period. Erase the recorded signal, then 1
A unit video signal for one frame is recorded on the recording medium 8 by the recording gate signal (FIG. 4f) that opens the gate 4 after a buffer period of the frame period, and after the recording is completed, the relay drive circuit 16 is activated. Then, the first and second switches are switched to the P terminal at the same time to immediately reproduce the signal just recorded, and when the reproduction operation for a predetermined period of time is completed, the operation of the relay is stopped and the monitor mode is returned to, and the motor is The drive circuit 43 is operated to advance the magnetic head to the next track.

When the play command button 25 is operated in the monitor mode, the output of the circular ring circuit 39 is inverted to a low level and the play mode is entered. However, even if the record command button 25 is operated by mistake at this time, the output is transferred to the NAND gate 33. , and the above operation will not occur. To return to the monitor mode, the monitor command button 24 can be operated. When the forward button 22 is operated by one track, a signal similar to the access trigger is input to the motor drive circuit 43 to advance the magnetic head 7 by one track. In addition, there is a button 23 for reversing by one track.
When operated, the mode of the motor mode switching circuit 45 is switched and at the same time the motor drive circuit 43 is driven to move the magnetic head backward by one track.
At this time, the output of the motor mode switching circuit 45 is provided to the logic circuit 39, which inverts the output to a low level and sets the reproduction mode. This also applies when the magnetic head is moved forward or backward by operating the track command operator group. Therefore, even if the recording command button 25 is operated by mistake during this backward movement, the contents of the intermediate track will not be erased or noise will not be recorded.

According to the device of the present invention, the circuit (mono multivibrator) 31 having a pulse width of sufficient time to extract a unit video signal is driven by the operation of the recording command button, and the output of the circuit is used to extract the unit video signal. In addition to driving the circuits 32 and 37 for extracting the data, the output of the circuit 31 is prohibited from being transmitted to the extraction circuits 32 and 37 during the access operation of the recording and reproducing head. Even if you press the recording command button by mistake during an access operation that moves across tracks to the target track, that command operation can be invalidated, and the recorded track will be erased (over-recorded) against your will. or by an erasing operation that precedes the recording operation)
This has the effect of preventing malfunctions that would otherwise occur.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the device of the present invention, Fig. 2 is a front view of the remote control operation section, Fig. 3 is an isolated circuit diagram of the gate generation circuit, Fig. 4 is a time chart for explaining its operation, and Fig. 5 is a FIG. 3 is a diagram showing the relationship between a recording medium and a magnetic head. 4...Frame gate circuit, 17...Remote control unit, 25...Record command button, 31...Mono multivibrator, 32...Counter, 40...Relay.

Claims (1)

[Scope of utility model registration request] By operating the recording command button, a unit video signal is extracted and the extracted signal is recorded on one track on the recording medium, and then the recording/reproducing head accesses the next track and enters the recording standby state. In the still image recording and reproducing apparatus configured as above, a circuit 31 having a pulse width of sufficient time to extract the unit video signal is driven by operation of a recording command button, and the unit video signal is outputted from the circuit 31. It is characterized by being provided with circuits 39 and 33 that drive the extracting circuits 32 and 37 and prohibit the transmission of the output of the circuit 31 to the extracting circuits 32 and 37 during the access operation of the recording/reproducing head. Still image recording and playback device.