JPH07105520A - Tracking adjusting device - Google Patents

Abstract

PURPOSE:To quickly perform a tracking adjustment by making the adjustment of delay time setting value possible only by operating one of either a count-up button or a count-down button. CONSTITUTION:This device is provided with a counter 2 being a delay time setting means changing a delay time setting value in one direction based on operations of a count-up button 11 and a count-down button 12 and a delay time storage means 15 storing the delay time setting value at the point of a time when operations of buttons 11, 12 are started and also provided with a control circuit 16 being a means detecting that the delay time setting value reached a prescribed adjustment range. Moreover, when the circuit 16 detects that the delay time setting value reached the adjustment range, the circuit 16 returns to the delay time setting value stored in the storage circuit 15 and changes the delay time setting value in another direction. Thus, since the delay time setting value is changed only by operating either the counter buttons, the tracking adjustment is performed quickly and also the operability of the device is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking adjusting device such as a video tape recorder (VTR).

[0002]

2. Description of the Related Art Conventionally, tracking servo in a VTR is performed on the basis of a reproduction control signal. However, when a video tape recorded by another VTR is reproduced, tracking adjustment may be deviated. Therefore, by operating the tracking adjustment button provided on the operation panel, the delay time of the reproduction control signal or the reference signal corresponding to the rotation of the rotary head is changed, and thereby the tracking adjustment is performed.

Conventionally, as the tracking adjustment button, a rotary type adjustment button for directly rotating the variable resistor or a slide type adjustment button is used, and the variable resistor is used when a good reproduced image is obtained. Center click point (default setting)
The compatibility between the video tape and the VTR can be determined by reading how much is deviated from. Further, when the video tape recorded by the VTR of its own is reproduced, the tracking value can be quickly set to the optimum value by returning the tracking adjustment button to the center click point.

By the way, in recent years, the rotary or slide type adjustment buttons have poor operability, and in order to improve the operability, the tracking adjustment buttons are often adopted as count-up buttons and count-down buttons ( JP-A-6
3-52139 gazette). As shown in FIG. 5, the device is provided with a count-up button 11 and a count-down button 12, and is connected with a counter 2 for storing the delay time setting value and the delay time setting value output from the counter 2 as an input signal. Microcomputer 4,
It is composed of a character generation circuit 7 controlled by the microcomputer 4 and a mixer 8 to which an output signal of the character generation circuit 7 and an input video signal from a video circuit system are connected, and is output from a counter 2. The delay time setting value is sent to the mono-multivibrator 5 that delays the reference signal for a certain time, via the D / R conversion circuit 3 that converts a digital value into a resistance value.

By operating the count-up button 11 or the count-down button 12, the delay time of the reference signal is adjusted, and the delay time set value stored in the counter 2 is output to the microcomputer 4 for processing and the setting. A display control signal corresponding to the value is created.

The horizontal synchronizing signal HS and the vertical synchronizing signal VS separated from the input video signal by the sync separating circuit 6 are connected to the character generating circuit 7, and the character generating circuit 7
A character information video signal to be displayed on the television screen is created based on the display control signal and output to the mixer 8. The mixer 8 mixes the input video signal and the character information video signal, creates an output video signal in which a character signal representing a tracking value is multiplexed, and supplies the output video signal to a television receiver.

In the above apparatus, as shown in FIG. 6, the user can operate the count-up button 11 and the count-down button 12 while looking at the display marks on the screen 21 to easily and quickly perform tracking adjustment. it can.
Also, by referring to this display mark 22, the tracking value can be adjusted.

The portion indicated by 1 is composed of a microcomputer.

[0009]

However, when performing the tracking adjustment in the above apparatus, the delay time set value is changed by operating the count-up button 11, for example.
When the tracking adjustment cannot be performed before the upper limit value of the adjustment range is reached, the user has to operate the countdown button to change the delay time setting value in the opposite direction to perform the tracking adjustment. Therefore, there is a drawback that it takes time to find the best delay time setting value. Further, both the count-up button and the count-down button have to be operated, which is very complicated and has poor operability.

The present invention has been made in view of the above-mentioned problems, and provides a tracking adjustment device which can perform tracking adjustment promptly by operating either one of a count-up button or a count-down button. .

[0011]

SUMMARY OF THE INVENTION According to the present invention, tracking servo is performed by phase comparison between a reproduction control signal from a video tape and a reference signal, and the delay time of the reproduction control signal or the reference signal is adjusted by operating a button. In a device for performing tracking adjustment by changing the delay time, a delay time setting means for changing the delay time setting value in one direction based on the button operation, and a delay time setting value at that time when the button operation is started are stored. A delay time storage means and a means for detecting that the delay time set value has reached a predetermined adjustment range, and when it is detected that the delay time set value has reached a predetermined adjustment range, The delay time storage means includes a control means for returning the delay time set value stored in the delay time storage means and for changing the delay time set value in the other direction.

[0012]

According to the above construction, the delay time set value is changed in one direction based on the operation of either the count up button or the count down button, and the delay time set value at the time when the button operation is started is set. Remember.

When it is detected that the delay time set value has reached the upper limit or the lower limit of the predetermined adjustment range, the stored delay time set value at the start of button operation is restored, and the delay time set value is set in the other direction. Since it can be changed, tracking adjustment can be performed in a short time and operability is improved.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention, and the same parts as those in FIG.

1 is different from FIG. 5 in that it has a storage circuit 15 for storing a delay time setting value (hereinafter, a count value) at the start of operation of a count up button or a count down button, and a count value is adjusted to a predetermined value. The point is that a control circuit 16 for detecting the reaching of the range and controlling the memory circuit 15 and the counter 2 is added. The portion indicated by 1 is composed of a microcomputer.

Referring to FIG. 1 in detail, the count-up button 11 and the count-down button 12 are connected to the up / down counter 2 via a limiter 13 that defines the upper and lower limits of counting. As will be described later, the limiter 13 receives the output of the counter 2 and prohibits the up-counting or down-counting input when it coincides with a preset value "0" or "31".

When the control circuit 16 detects the start of the operation of the count-up button or the count-down button from the limiter output, it stores the current count value in the storage circuit 15, and the control circuit 16 stores the count value in advance. When it detects that the upper limit or lower limit of the set adjustment range is reached,
The count value stored in the memory circuit 15 is set in the counter 2, and the count operation of the counter 2 is changed in the opposite direction.

An initial setting circuit 14 is connected to the counter 2, and the operation of the circuit 14 presets the counter 2 to an initial value serving as a center click point. The initial setting circuit 14 operates when the VTR is turned on, when the cassette tape is taken in and out, and when a reset circuit (not shown) is activated.

The count value output from the counter 2 is sent to the microcomputer 4 and
It is sent to the D / R conversion circuit 3. The D / R conversion circuit 3
For example, as shown in FIG. 4, analog switches S1 to S5 whose opening and closing are controlled by binary signals b1 to b5 output from the up / down counter 2 and resistors R1 to R1 divided and connected to both ends of each analog switch. R5, and each analog switch opens and closes according to the output signal of the counter 2. The counter 2 is preset to "15" by the initial setting circuit 14. Each resistance value with R1 as a reference is R2 = 2 · R1, R3 = 4 · R1, R
4 = 8 · R1 and R5 = 16 · R1, and in the embodiment, R was selected to be about 100 ohms.

Generally, a tracking delay time of ± 10 milliseconds from the center value is sufficient. The change width may be about 1 millisecond. In addition, the intermediate value of the counter 2 is set to "1.
If it is set to "5", a variable width of ± 15 steps can be obtained. Therefore 1
It was designed to have a change width of about 0.7 milliseconds per step. Further, when the counter 2 is "15", the delay time of the monomulti 5 is set to 33.3 milliseconds. Incidentally, 33.
3 milliseconds corresponds to one cycle of the reproduction control signal.

By opening / closing the analog switch, a voltage signal corresponding to the magnitude of the delay time setting value is output to the mono-multi 5, and as a result, the reference signal connected to the mono-multi 5 is set in the counter 2. It is delayed by time and supplied to a phase comparator (not shown) equipped on the speed servo,
Tracking adjustment is performed.

On the other hand, the delay time set value output to the microcomputer 4 is temporarily stored in the RAM. A data display program as shown in FIG. 6 is set in the RAM of the microcomputer 4.

Next, the operation of the present invention will be described with reference to the flowcharts of FIGS. Note that this flowchart shows the operation when the count-up button is operated. That is, it is detected whether or not the count-up button 11 has been operated (step S1), and when it is detected that the count-up button 11 has been operated, the current count value of the counter 2 is stored in the storage circuit 15 (step S2). And count up button 1
When 1 is continuously operated (step S3), the count value of the counter 2 is increased by one step (step S4) at a predetermined cycle (for example, 0.3 seconds), and the count value is increased by the D / R conversion circuit 3 (Step S5). D /
As described above, the R conversion circuit 3 outputs the voltage signal according to the magnitude of the count value to the monomulti 5, and the desired tracking adjustment is performed. This operation is sequentially performed until the count value of the counter 2 becomes "31", and if good reproduction is obtained before the count value becomes "31" or less, the operation of the count-up button 11 is ended. By performing (step S25), a good reproduced image can be viewed.

When the count value of the counter 2 reaches "31", a timer circuit (not shown) operates (step S7), and the time during which the count-up button is operated is
For example, when one second is measured (steps S8 and S9), the count value stored in the storage circuit 15 is set in the counter 2 (step S10). Here, the timer circuit measures the predetermined time in order to ensure that the tracking adjustment operation is stably performed by the upper limit "31" of the count value.

Then, when the count value stored in the memory circuit 15 is set in the counter 2, the timer circuit operates as described above (step S11), and the time during which the count-up button is operated is measured (step S11). S12, S1
3) Do. In this case as well, the predetermined time is set in the timer circuit so that when the count value of the counter 2 is returned to the value at the start of the count-up button operation, the tracking adjustment is stably performed at that value. This is because

Next, it is checked whether or not the count-up button 11 is continued (step S14), the count value of the counter 2 is decreased by one step at a predetermined cycle (step S15), and the count value is D / It is supplied to the R conversion circuit 3 (step S16). As described above, the D / R conversion circuit 3 performs desired tracking adjustment based on the count value. This operation is sequentially performed until the count value of the counter 2 becomes "0", and if good reproduction is obtained before the count value becomes "0", the operation of the count-up button 11 is terminated ( By performing step S25), a good reproduced image can be viewed.

When the count value of the counter 2 reaches "0", the timer circuit operates (step S18), and the time during which the count-up button is operated measures, for example, 1 second (step S19, S20), memory circuit 1
The count value stored in 5 is set in the counter 2 again (step S21).

The above operation can be repeated, but when a good reproduced image cannot be obtained, the operation of the count-up button 11 is terminated when an appropriate reproduced image is obtained.

In the flow chart of this embodiment, the case where the count-up button 11 is operated has been described. However, when the count-down button 12 is operated, steps S1, S3,
The count-up button in S12, S14, S19, and S23 is changed to a count-down button, and the description of 1 step up in step S4 is changed to 1 step down, and step S1 is changed.
Change 1 step down description in 5 to 1 step up. Further, the upper limit value “31” in step S6 is set to the lower limit value “0”, and the lower limit value “0” in step S17 is set to the upper limit value “3”.
You can change it to 1 ”.

Further, in this embodiment, the count-up button 11
Although the countdown button 12 is provided, it may be controlled by one countup button or one countdown button.

[0031]

According to the present invention, the delay time set value can be adjusted by operating either the count-up button or the count-down button, so that the tracking adjustment can be performed quickly and the operability is improved.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part of a tracking adjustment device embodying the present invention.

FIG. 2 is a flow chart when the operation of the present invention and a count-up button are operated.

FIG. 3 is a flow chart when the operation of the present invention and a count-up button are operated.

FIG. 4 is a diagram showing a D / R conversion circuit.

FIG. 5 is a block diagram of a main part of a conventional tracking adjustment device.

FIG. 6 is a diagram showing a tracking value display screen of a conventional device.

[Explanation of symbols]

 11 Count-up Button 12 Count-down Button 15 Storage Circuit (Delay Time Storage Means) 16 Control Circuit 2 Counter (Delay Time Setting Means) 3 D / R Conversion Circuit 5 Mono Multi

Claims (1)

[Claims] 1. A device for performing tracking servo by phase comparing a reproduction control signal from a video tape and a reference signal and performing tracking adjustment by changing a delay time of the reproduction control signal or the reference signal by operating a button. And a delay time setting means for changing the delay time set value in one direction based on the button operation, and a delay time storage means for storing the delay time set value at the time when the button operation is started. And a means for detecting that the delay time set value has reached a predetermined adjustment range, and when it is detected that the delay time set value has reached a predetermined adjustment range, the delay time storage means A tracking adjustment device comprising a control means for returning to the stored delay time setting value and changing the delay time setting value in the other direction.