JPH04141848A - Vtr index code write system - Google Patents

Abstract

PURPOSE:To write an index code with a simple operation by providing a rewind amount setting circuit, a comparison circuit for rewind amount and an index code write control circuit controlling the writing of the index code by means of the write signal of the index code. CONSTITUTION:If the index code is to be written in an arbitrary case while a registered tape is skip-viewed by speed search, the tape in an arbitrary length is rewound by an index code write controller 6 when the write switch for index code is depressed. Then, the same scene is reproduced in normal reproduction. When the write switch is depressed again when a tape returns to a position into which the index code is to be written, the index code is automatically written. When the writing of the index code terminates, a system automatically shifts to speed search at an original high speed reproduction A mode. Thus, the index code can be written only by depressing the write switch of the index code twice.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a VTR index code writing system.

[Conventional technology]

The index code of a VTR is a signal for locating the beginning of a recorded signal, and this signal uses a control signal that serves as a reference for controlling the drive motor of the VTR during playback.

The control signal read from the tape during playback is called a playback control signal, and the rising edge of this signal is used as the reference for motor control.

Recently, VHS-type VTR systems use the above-mentioned control signals to perform VIS, a new cueing function.
Added S (VHS Index Search System).

This VISS functionality is based on two control signal duty ratios: 60:40 and 27.5 near-2.
．． 5, the former corresponds to the logical value "0" of the signal, and the latter corresponds to the logical value "1" of the signal, and by combining these "0" and "1", an index code is formed. be.

Therefore, if you write an index code at the position where you want to cue, the index code can be instantly searched during playback and the cue can be found. Furthermore, in most cases, not only reading but also writing is performed during playback.

An example of a conventional VTR index code writing system is shown in FIG.

In FIG. 5, the conventional VTR index code writing system 3 operates by manually inputting keys from the front panel 1.
An instruction register 4 receives a control signal from a system controller 2 that converts the operation mode signal of the TR into a serial digital signal, and receives the control signal.
an instruction decoder 5 that converts the output signal of the instruction decoder 5 into an individual mode signal instructing each constituent block; an index code generation unit 7 that receives the output signal of the instruction decoder 5 and generates an index code signal; A control signal write timing generation section 8 generates the timing for writing the index code, a control signal generation section 9 receives the timing signal and outputs a pulse signal for writing the index code to the control pad 11, and The reproduction control logic signal generating section 10 receives a reproduction control signal and converts it into a logic pulse.

Next, the operation of the conventional VTR index code writing system will be explained.

First, when an index code writing instruction switch is pressed on the front panel 1 of the VTR, the system controller 2 converts the index code into a serial digital signal, as in other operating modes of the VTR.

Next, the serial digital signal for index code writing instruction is input to the instruction register 4 of the VTR index code writing system 3.

The output signal of the instruction register 4 is converted into an individual operation mode signal for each block by an instruction decoder 5, and is output to each functional block.

The index code write mode signal, which is the output of the instruction decoder 5, is input to the index code generation section and an index code is generated. This is code data in which 61±3 "1"s are written between the reference "0" at the beginning and the "0" at the end of the data.

The second code data is written on the tape by the control signal generation section 9 and the control radar 11 according to the timing generated by the control signal writing timing generation section 8.

The technical problem of this system is to write the index code control signal without disturbing the rising edge of the control signal that has already been written to the recorded image.

In addition, even if the rising edge of the control signal that has already been written is not disturbed, when writing a new signal, do not write a pulse that may be misjudged as a rising edge at a different position. Due to this restriction, the timing of writing the index code can be said to be extremely delicate.

Therefore, in the conventional VTR index code writing system, when writing an index code, it is always done in the normal mode, which is 1x speed, and no writing instructions are accepted in other double speed modes.

[Problem to be solved by the invention]

In the conventional VTR index code writing system described above, when writing an index code,
There is a drawback that it must be performed in normal mode, which is 1x speed.

Therefore, when attempting to write an index code during speed search playback at double speed or higher, there is a drawback in that it is necessary to switch the playback mode of the V-TR to normal mode.

[Means to solve the problem]

The VTR index code writing system of the present invention includes:
An operation mode control circuit that controls the selection of the VTR operation mode using an operation mode signal composed of a predetermined code, and an index code write signal generation that instructs writing of an index code, which is a signal for cuing up the recording signal. a rewind amount setting circuit for setting a predetermined tape rewind amount when receiving the operation mode signal; and a rewind amount setting circuit for writing the index code. a comparison circuit that compares the set value of the rewinding amount with the rewinding amount after the VTR starts rewinding in response to the index code write signal; The apparatus includes an index code write control circuit that controls writing of the index code.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of the present invention.

In FIG. 1, the VTR index code writing system 3 of the present invention is a conventional technology in which a control signal is input from a system controller 2 that converts a VTR operating mode signal manually inputted from a front panel 1 into a serial digital signal. An instruction register 4, an instruction decoder 5, an index code generation section 7, a control signal write timing generation section 8, a control signal generation section 9, a reproduction control logic signal output section 10, and a control circuit similar to those shown in FIG. In addition to the index code 11, the index code write controller 6 receives the index code write mode signal which is the output of the instruction decoder 5 even in the speed search mode, and controls the index code to be written at an arbitrary position. ing.

Next, the operation of this embodiment will be explained.

First, the general operation of index code writing is the same as that shown in the example of the prior art described above, and the explanation will be omitted here since it will be redundant.

Next, as an aid to understanding the functions of the VTR index code writing system of this embodiment, the flowchart shown in FIG. 2 will be explained.

First, let us consider a case in which an index code is to be written at an arbitrary scene during a tour of a recorded tape using, for example, speed search in high-speed playback mode A (step R1).

At this point, press the index code write switch on the front panel 1 (step R2).

When the index code write switch is pressed, the index code write controller 6 first rewinds the tape by an arbitrary length, that is, performs reverse playback, in accordance with the high-speed playback A mode at that time (step R3).
.

Next, in normal playback, the same scene is played again (step R4), and when the user returns to the position where the index code was to be written, the write switch is pressed again (step R5).

Here, the present system automatically writes the index code at the optimal timing (step R6).

When writing of the index code is completed, the process automatically shifts to the speed search of the original high-speed playback A mode (step R7).

As described above, the operator can write an index code even in any speed search mode by simply pressing the index code write switch twice.

FIG. 3 shows an example of the configuration of the index code writing controller 6 that controls the above functions.

In FIG. 3, the index code writing controller 6 of this embodiment receives the reproduction control logic signal from the reproduction control logic signal generation section 10, and
A tape speed detection circuit 61 that monitors the current speed search, a decoder 62, two preset value generation circuits 63 and 64, two counter circuits with presets 6567, two zero detection circuits 66 and 68, and a mode command. It has six circuits.

Next, the operation of the index code write controller 6 will be explained.

First, upon receiving a playback control signal written on the tape from the control controller 11 and receiving a playback control logic signal from the playback control logic signal generator 10 which converts it into a logic pulse, the tape speed detection circuit 61 detects the current speed. Monitor speed search.

Upon receiving the operation mode signal from the instruction decoder 5, the decoder 6
2 and the preset value generation circuit 63 sets the rewind time to the counter circuit with preset 65, and the preset value generation circuit 64 sets the rewind time to the counter circuit with preset N67, and waits until the index code write mode signal is input. There is.

When the index code write switch is pressed, an index code write mode signal is input from the instruction decoder 5, and the preset counter circuit 6 is inputted from the instruction decoder 5.
The tape is played in reverse for the rewind time set in 5.

This detection is performed by the zero detection circuit 66 when the count value becomes zero with respect to the set value of the preset counter circuit 65.
I'll do it at

After being rewound by the set time, it switches to normal playback and waits for the index code write switch to be pressed again.

When the index code write switch is pressed and the index code write mode signal is input, the index code write signal is input from the six mode command circuits to the index code generation section 7, an index code is generated, and the control signal write timing is input. The information is written onto the tape according to the timing output by the generation unit 8.

Here, when the generation of the index code in the index code generation section 7 is completed, the completion signal is the mode command time of the index code writing controller 6? @6 is input and the original speed search state is restored.

Also, if the -th index code write switch is pressed and the switch is not pressed while waiting for the second switch to be pressed during normal playback, the count value of the preset counter 11867 becomes zero. In response, a zero detection signal is output from the zero detection circuit 68, and the speed returns to the original speed at a position slightly advanced from the position where the -th switch was pressed.

Furthermore, the index code writing during normal playback is the same as the conventional one.

Next, a second embodiment of the present invention will be described.

The difference from the first embodiment is the configuration of the index code write controller 6.

FIG. 4 is a block diagram of an index code write controller 6 showing a second embodiment of the present invention.

In FIG. 4, the index code writing controller 6 of this embodiment includes a mode command circuit 69, an up/down counter circuit 71, a memory circuit 72, and a comparison circuit 73 similar to those of the first embodiment. There is.

In the first embodiment, when the index code write switch is pressed during a speed search, the film is rewound once at the speed of the speed search, then normal playback is performed, and the system waits for the index code write switch to be pressed again. It was something.

In this embodiment, when the index code write switch is pressed during speed search, the tape count value at that time is memorized, and up to the tape count value -
Once the tape is returned, normal playback and index code writing are automatically executed.

Next, the operation of this embodiment will be explained.

First, the up/down counter circuit 71 receives the operation mode signal from the instruction decoder 5 and counts the reproduction control logic signal from the reproduction control logic signal generation section 10 as a clock. In this case, when the tape running direction is forward, it counts up, and when it runs reverse, it counts down.

Moreover, the count value of the up/down counter circuit 71 is
It is always input to the memory circuit 72.

When the index code write signal is input in a mode other than normal playback, the count value at that time is held by the storage circuit 72.

The tape is once rewound in the reverse direction by the operation mode signal from the mode command circuit 69. Next, the tape is rewound in the forward direction until the count value of the up/down counter circuit 71 matches the count value held in the memory circuit 72. When the two match, the comparison circuit 73 outputs a match signal to the six mode command circuits.

When the mode command circuit 69 receives the coincidence signal, it outputs a normal reproduction mode command signal and an index code write signal to write the index code on the tape.

Although the present invention has been described in detail above, the present invention is not limited to the above embodiments and can be modified in various ways.

〔Effect of the invention〕

As explained above, the present invention has the advantage that in a VTR index code writing system, an index code can be written by a simple operation even in any speed search mode without the complicated operation of switching to normal playback mode. There is.

Therefore, it is possible to provide a VTR that is highly functional and easy to operate.

[Brief Description of the Drawings] Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a flowchart for explaining the functions of the circuit shown in Fig. 1, and Fig. 3 is a block diagram showing an embodiment of the present invention. FIG. 4 is a block diagram showing an index code writing controller according to a second embodiment of the present invention, and FIG. 5 shows an example of a conventional VTR index code writing system. FIG. DESCRIPTION OF SYMBOLS 1... Front panel, 2... System controller, 3... VTR index code writing system, 4... Instruction register, 5... Instruction decoder, 6... Index code writing controller, 7... - Index code generation section, 8... Control signal write timing generation section, 9... Control signal generation section, 10... Playback control logic signal output section, 11... Control head, 61... Tape speed Detection circuit, 62・
... Decoder, 63.64 ... Reset value generation circuit, 65.67 ... Counter circuit with preset, 66.
68... Zero detection circuit, 69... Mode command circuit,
71...up/down counter circuit, 72...memory circuit, 73...comparison circuit.

Claims (1)

[Claims] 1. An operation mode control circuit that controls the selection of the operation mode of the VTR using an operation mode signal composed of a predetermined code, and writing of an index code that is a signal for cuing up the recording signal. and an index code write signal generation circuit for writing the index code, the rewinding amount setting a predetermined tape rewinding amount when the operation mode signal is received. a setting circuit; a storage means for storing the set value of the rewind amount; and a comparison circuit that compares the set value of the rewind amount with the rewind amount after the VTR starts rewinding according to the index code write signal. , a VT characterized in that it has an index code write control circuit that controls writing of the index code by the write signal of the index code.
R index code writing system. 2. The rewind amount setting circuit is characterized by having a tape speed detection circuit that detects a tape speed, and a rewind amount setting circuit that sets a predetermined rewind amount of the tape according to the tape speed. The VTR index code writing system according to claim 1. 3. The rewind amount setting circuit includes an up/down counter circuit that counts a pulse train generated from a playback control signal read from the tape and outputs a position count value of the tape, and 2. The VTR index code writing system according to claim 1, further comprising a storage circuit for storing a position count value, and a comparison circuit for comparing the count value stored in the storage circuit with the position count value.