JPS6359584B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a video signal reproducing apparatus, and is particularly suitable for use in apparatuses equipped with high-speed picture search modes such as queue and review modes.

In a recording/playback device such as a video tape recorder (VTR) that has a high-speed picture search mode such as queue or review, if you switch to high-speed search mode while operating in a mode such as standard playback or triple-speed playback, When you cancel search mode
The VTR now returns to its original playback mode. Therefore, it is possible to search for a playback location using a high-speed search while looking at the playback screen. Furthermore, since it returns to the original playback mode from high-speed playback, it is also useful for protecting the tape by avoiding sudden tape deceleration.

For this reason, in general, you need to operate the pause button to
When operating in still playback mode or by operating the playback speed variable knob in pause mode.
If you perform a high-speed search while the VTR is operating in slow-motion playback mode, the
The VTR is configured to return to standard playback mode.

Therefore, it is not possible to interpose a high-speed search during still playback (or slow motion playback) to search for a still image that is desired to be played back. In other words, with the above-mentioned VTRs, performing a high-speed search cancels the previous still playback mode or slow-motion playback mode, so how to return to the original still or slow-motion playback mode after canceling the high-speed search mode The user had to operate the pause button or variable playback speed knob again, which resulted in poor operability.

The present invention solves the above-mentioned problems.

The video signal reproducing device of the present invention includes a first operation switch for setting a high-speed playback mode of queue or review, a second operation switch for setting a still playback mode or a slow-motion playback mode, and a second operation switch for setting a high-speed playback mode of queue or review. a storage circuit which inputs a still playback or slow motion playback mode signal set by the operation output of and the operation output of the first operation switch, and stores the mode signal at the time of operation of the first operation switch;
The operation outputs of the first and second operation switches and the output of the memory circuit are respectively input, and the second
and a mode setting circuit that generates the mode signal when the operating switch is operated. When the first operation switch is operated during pause playback or slow motion playback set in accordance with the mode signal, the mode setting circuit cancels the mode signal, and then When the operation switch is released, the mode signal is reset by the output of the memory circuit.

With this configuration, even if the still or slow playback mode is canceled when the high-speed search mode is entered, it will be reset at the end of the high-speed search mode, so you can perform a high-speed search while looking at the still playback image or slow playback screen. This makes it possible to search for a still screen or slow screen that you want to play back with a simple operation.

The present invention will be described below with reference to drawings of embodiments.

FIG. 1 is a circuit diagram of a mode control circuit for a VTR showing one embodiment of the present invention. This VTR is equipped with a key switch 1 and a review switch 2 for high-speed picture search. Reference numeral 3 denotes a pause switch consisting of a non-locking push switch. When this switch 3 is operated, a low level pulse is supplied to the trigger input of the flip-flop 5.
is set. This flip-flop 5 constitutes a mode setting circuit 10. The set output of flip-flop 5 is used as a pause control signal.
It is supplied to the system control circuit 6 of the VTR, and is also supplied to the light emitting diode 7 to control the VTR.
is displayed to indicate that it is in pause mode. Note that when the pause switch 3 is operated and a playback speed variable knob (not shown) is operated, slow playback can be performed at an arbitrary speed.

When the pause switch 3 is operated again in the pause mode, the flip-flop 5 is reversed, the pause state is canceled, and the VTR returns to the standard playback mode.

Next, a case will be explained in which the key switch 1 or the review switch 2 is operated when the VTR is in the pause mode. In the pause mode, flip-flop 5 is in the set state as described above, so a high level signal is supplied from the set output of flip-flop 5 to the base of transistor Q2 via diode D3. Therefore, transistor Q2 is in a state where it can be turned on. Note that the transistors Q2 and Q3 are thyristor-connected with their bases and collectors connected to each other, and these transistors Q2, Q3
serves as a memory circuit 11 for storing the pause state.

When the cue or review switches 1 and 2 are operated, a low level signal is generated by these switches and this signal is supplied to the system control circuit 6 to place the VTR in the cue or review mode. Since the low level output of switch 1 or 2 is also supplied to negative logic OR gate 4, output a shown in FIG. 2A is obtained from this gate 4. This output a is supplied to the base of transistor Q1 via diode D1, so Q1 is turned on. When transistor Q1 is turned on, transistor Q2 is also turned on, which also turns on transistor Q3. The on state of transistor Q2 is maintained by turning on transistor Q3. Note that since the output a of the OR gate 4 is supplied to the clear input CL of the flip-flop 5, the flip-flop 5 is cleared and its set output c becomes a low level as shown in FIG. 2C. For this reason, the light emitting diode 7 that displays the pause state is turned off during the Kyureview.

The key switch 1 and the review switch 2 are non-locking push switches, and while they are kept pressed, a high-speed picture search for queue or review is performed. When these switches 1 and 2 are released, the output a of the OR gate 4 falls as shown in FIG. 2A. Since a capacitor C1 and a resistor R1 are connected between the ground and the cathode of the diode D1 for transmitting the output of the OR gate 4 to the base of the transistor Q1, the base voltage b of the transistor Q1 is as shown in FIG. 2B. It falls with a time constant determined by capacitor C1 and resistor R1. Therefore, since the turning off of transistors Q1, Q2, and Q3 is delayed by a certain period of time from the falling edge of signal a,
The voltage d on the output line of the pause switch 3, which is connected to the collector of the transistor Q2 via the diode D2, is at a low level when the queue and review switches 1 and 2 are released, as shown in FIG. 2D. As a result, Kyuu, Revue Switch 1
Or, at the time of release of 2, the same state as operating the pause switch 3 occurs, the flip-flop 5 is reversed to the set state, and the VTR returns to the pause mode, which is the mode before picture search, and plays stills. Or slow playback is performed.

If the VTR is not in pause mode at the time you operate cue or review switches 1 and 2, flip-flop 5 is in the reset state and the output of flip-flop 5 is at a low level, so operate switches 1 and 2. When this occurs, transistors Q2 and Q3 do not turn on. Therefore, since the flip-flop 5 is not set when the cue or review switches 1 and 2 are released, the VTR returns to the normal playback mode, fast playback mode, etc. before the switches 1 and 2 were operated.

Next, FIG. 3 shows a VTR showing another embodiment of the present invention.
It is part of the control circuit. In this embodiment, when the search mode is canceled after performing a high-speed picture search for queues and reviews in the pause mode, the mode returns to the pause mode via the standard playback mode for a certain period of time. One of the reasons for inserting the standard playback mode is to protect the tape. That is, when returning from the high-speed search mode to the pause mode, the tape speed changes suddenly and the tape may be damaged. For this reason, the standard playback mode is placed between the search mode and the pause mode to prevent the tape speed from changing rapidly.

Furthermore, the recording tape speed can be determined using the period of the standard playback mode. With VTRs that allow you to select various tape speeds for recording, such as 1-hour recording, 2-hour recording, 3-hour recording, etc., the frequency of the control signal recorded on the side edge of the tape is detected during playback, and the recording speed is adjusted accordingly. The tape speed is automatically controlled to be the same as the tape speed. If the recording tape speed has been changed in various ways during a single tape, when the pause switch is operated as described above, and the playback speed variable knob is also operated to set the VTR to slow playback mode, high-speed picture When you enter the player search mode, you may be in a state where a portion of the recorded tape speed is played back. In this case, if the configuration is configured to return to slow playback mode after canceling search mode as in the first embodiment,
Since the recording tape speed cannot be detected, the same slow playback speed as before the search mode cannot be reproduced after the search mode is released. For this reason, standard playback is performed for a certain period of time after the search mode is canceled, and the recording tape speed is detected during this period.

Furthermore, when returning to still playback mode after canceling search mode, standard playback mode is inserted as described above, and this period is used to control the tape stop position, thereby eliminating band noise on the still playback screen. You can prevent this from occurring.

In order to perform the above-described operation, the mode setting circuit 10 shown in FIG. 1 is connected to the control circuit 1 shown in FIG. 3.
0a can be added. In FIG. 3, when the cue or review switches 1, 2 are operated as in FIG. 1, a high level signal a shown in FIG. 4A is generated from the output of the OR gate 4. Since this signal a is supplied to the base of transistor Q4 via inverter 8, transistor Q4 is turned off in the search mode.
Therefore, transistor Q5 is also off.

When the queue or review switches 1 and 2 are released, the transistor Q4 is turned on, so that the base current of the transistor Q5 flows through the resistor R2 and the capacitor C2 to the collector of the transistor Q4, and the transistor Q5 is turned on. Transistor Q5 is on for a time constant determined by capacitor C2 and resistor R2, and is turned off when capacitor C2 is charged. As a result, the collector output e of the transistor Q5 remains at a high level for a predetermined period after the cue/revue switches 1 and 2 are released, as shown in FIG. 4B. This output e
is supplied to the negative logic AND gate 9.

On the other hand, as explained in FIG. 1, the output c (pause signal) of the flip-flop 5 is used to operate the pause switch 3 as shown in FIG. 2C or FIG. Even if you don't, you will return to a high level. This pause signal c is supplied to the AND gate 9 after being converted into an inverted signal. Therefore, a signal f (delayed pause signal) shown in FIG. 4D is formed from the output of the AND gate 9.
This signal f rises after a certain time delay from the time when the search mode is released. This signal f is supplied to the system control circuit 6, and this control circuit 6
Since the servo circuit 10 of the VTR is controlled by the output, standard speed playback is performed during the period (for example, about 1 to 2 seconds) from when the cue or review switches 1 and 2 are released until the delayed pause signal f rises. .

Note that by using the edge of the reproduction control signal CTL (E in Figure 4) obtained during standard reproduction, a control signal as shown in Figure 4F is formed, and a certain period of time τ has elapsed since the rise of this signal. Later, a brake signal for the tape running system as shown in FIG. 4G can be formed. Since the control signal CTL indicates the position of the recording track on the tape, if the above time width τ is determined by taking into account the inertia of the tape running system (for example, the tape reel stand), it is possible to control the rotation of the rotating video head when the tape is stopped. The phases of the scanning locus and recording track can be matched. In this state, the rotating video head does not scan across adjacent tracks of different dimensions, so band noise does not occur in the still reproduced image and a high quality image can be obtained.

As described above, when the present invention performs high-speed playback of queue or review in the still playback mode or slow motion playback mode,
Even if the still playback mode or slow-motion playback mode is canceled, these modes are reset when high-speed playback ends, so you can search for the still image or slow-motion image you want to play by clicking or reviewing. , and the operations for that purpose do not become complicated.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a VTR mode control circuit showing one embodiment of the present invention, Fig. 2 is a time chart for explaining the operation of Fig. 1, and Fig. 3 is another embodiment of the present invention. FIG. 4 is a partial circuit diagram of a mode control circuit of a VTR, and FIG. 4 is a time chart for explaining the operation of FIG. In addition, in the symbols used in the drawings, 1...
... Key switch, 2... Levy switch, 3
...Pause switch, 6...System control circuit.

Claims (1)

[Claims] 1. A first operation switch that sets a high-speed playback mode of queue or review, a second operation switch that sets a still playback mode or a slow-motion playback mode, and operation of the second operation switch. a storage circuit which inputs a still playback or slow motion playback mode signal set by the output and the operation output of the first operation switch, and stores the mode signal at the time of operation of the first operation switch; a mode setting circuit which receives the operation outputs of the first and second operation switches and the output of the storage circuit, respectively, and forms the mode signal when the second operation switch is operated; When the first operating switch is operated during pause playback or slow motion playback set according to the signal, the mode setting circuit cancels the mode signal and then switches the first operating switch. A video signal reproducing device characterized in that when the mode signal is released, the mode signal is reset by the output of the storage circuit. 2. The video signal reproducing device according to claim 1, wherein when returning to the still playback mode or the slow playback mode, the return is performed after performing standard speed playback for a predetermined period.