JPS62146454A - Video tape player - Google Patents

Abstract

PURPOSE:To adjust rapidly tracking by providing a display means for displaying a delay time setting signal value, changing the contents of a counter over the whole variable range, and storing the position of the best reproducing image. CONSTITUTION:To adjust tracking by operating UP/DOWN switches 1, 2, a VTR is set to a normal reproducing mode, a mark 75 is moved to all positions in a range 72 and the position of the mark 75 indicating the best reproducing picture is stored. The mark 75 is moved to the stored position to end the tracking adjustment of normal reproducing. Then, the VTR is set up to a slow reproducing mode and similar operation is executed to execute tracking adjustment at the slow reproducing. Thus, the tracking adjustment can be rapidly executed by storing the position of the best reproducing image.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a videotape player having a playback function such as a videotape recorder (VTR), and which displays a tracking adjustment value.

(b) Conventional technology When a videotape is played back using a VTR, a tracking servo is applied. This tracking servo is performed based on the playback control signal, etc. However, when playing back video tapes recorded on other VTRs, or when playing back video tapes that have been expanded due to aging, the tracking may shift. . For this reason, VTRs vary the amount of delay (delay time) of the playback control signal or the reference signal corresponding to the rotation of the rotary head for tracking purposes.
Make adjustments.

An example of this tracking servo will be explained with reference to FIGS. 4 and 5.

During reproduction, this circuit uses the control signal reproduced by the control head (CTL head) (55) and the reference oscillation circuit (54) for driving the head motor (51).
Tracking correction is performed using the 30t (z reference signal) from ).

The correction method is to delay the reference signal in the tracking delay section (56), and to output the CTL pulse (58) in the comparator circuit (59).
) is compared and detected and fed back to control the speed and phase of the capstan motor (57).

The amount of correction can be adjusted by changing the time for which the base 4m signal is delayed in the tracking delay section (56).For this purpose, the VTR's operation section is provided with a tracking knob. There are rotating and sliding types of knobs. In order to delay the reference signal in this tracking delay section (56), a monomulti circuit is used, and the delay time is changed by using the C-R integral time constant and making the resistor R a variable resistor. ing.

FIG. 5 schematically shows a monomulti circuit forming the tracking delay section. In FIG. 5, (61) is a monomulti IC2 (63) is a variable resistor (trunking volume), and (64) is a capacitor.

In addition, (62), (63), and (64) constitute a time constant circuit,
The metastable period (delay time) in the mono multi-circuit 3b61> is determined.

The above operation will be explained. As can be seen from FIG. 4, the head motor (51) rotates in synchronization with the reference signal from the reference oscillation circuit (54). And the capstan motor (57
) rotation (tape running) is synchronized with the rotation of the video head using a reference signal. Therefore, the video head can always scan the center of the video track. Also, other V
A tracking delay section (56) is provided for compatibility with video tapes recorded with TR. When adjusting the tracking/y-king, the user should directly adjust the variable resistor (63) shown in Figure 5 while viewing the reproduced image so that the reproduced image becomes the best.
Arrange. Or, as shown in Utility Model Application No. 59-165009, Utility Model Application No. 59-139503, and JP-A-56-78282, directly connect the variable resistor (63) to maximize the playback envelope output! lt.

In the conventional example described above, the tracking 11 is performed by varying the amount of delay of the reference signal (signal corresponding to the rotational phase of the video head).
This may be done by adjusting the delay amount of the reproduction control signal from the CTL head (55). Further, tracking control is performed not only during normal playback but also during intermittent slow playback, for example.

Regarding this tracking servo, please refer to pages 136-141 of 1 Television Society Practical Book Series "Introduction to Home VTR" published by Corona Publishing, and 1 Human VTRJ (7) P 105P L18F 1 published by Tokyo University Press.
19P 192P 193, Jitsugan Sho 59-122148
No., JP-A No. 57-42278, the applicant of this case was filed in 1986.
This is a very well-known configuration that has been described in various documents such as the utility model registration application <10) filed on October 23, 2015.

As shown in the above-mentioned document, the tracking IT resistor for normal tracking adjustment is composed of a variable resistor.

However, as shown in utility model registration application (12) filed by the applicant on November 20, 1985, there is a VTR that performs tracking using up and down switches.

(・1> Problems to be solved by the invention By the way, when tracking is performed using the up and down switches, it is difficult to tell how much the tracking of the videotape being played back is off. In other words, when using the conventional variable resistor When adjusting the tracking with a device, the compatibility of the videotape and VTR can be determined by how much the variable resistor is rotated from the reference position where the center click is turned on when a good reproduced image is displayed.

However, when adjusting tracking using the up and down switches, the tracking deviation cannot be detected unless you consider how many times the up and down switches are pressed and how long they are pressed each time. .

Therefore, when tracking adjustment is performed using the up and down switches, it is difficult for the user to determine the degree of compatibility (tracking deviation amount) between the VTR and the videotape.

2) Means for Solving the Problems The present invention is a VTR equipped with a display means for displaying the amount of deviation of the tracking servo.

(e) Effects Since the present invention has the above-described configuration, the amount of tracking deviation is shown to the user by the display means, so the user can know the degree of compatibility between the videotape and the VTR.

(F) Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 to 3.

First, the tracking delay section is shown in Figure 2. In Figure 2, (3) is a 5-bit up/down counter.
It is preset to "15" by the initial setting circuit (4). (1) is an input switch for up counting, (2) is an input switch for down counting, b1 to b5 are the binary outputs of the 5-bit counter (3), and b1 is the lowest pit. (5) is a circuit that converts a digital value into a resistance value (hereinafter referred to as the D-R conversion circuit). This part consists of an analog switch (Sl) consisting of a relay or CMO8 IC.
(S5) and divided resistors (R1) to (R5). Each resistance value is R2-2・R1 with R1 as a reference.
, R3-4-R1, R4-8.R1, and R5-16R1. The embodiment selected R to be about 100 ohms. 6) is a capacitor. When the output of the counter (3) is "31", the resistor (7) is connected to (R1) to (R5).
) is short-circuited by the switches (Sl) to (S5) and the resistance component is prevented from becoming zero.

In general, it is sufficient for the tracking delay time to be ±10 milliseconds from the center value, and the range of variation is also about 1 millisecond, and if the intermediate value of the counter is "15", then ±15 milliseconds is sufficient.
A variable width of steps is obtained.

Therefore, it was designed to have a variation width of about 0.7 milliseconds per step. Further, when the counter (3) is "15", the delay time of the monomulti (8) is 33.3 milliseconds.

Note that 33.3 milliseconds corresponds to one period of the reproduction control signal. The input circuit of the counter (3) has a limiter circuit (not shown in Figure 2), which prohibits up-count input when the counter value reaches 31", and prohibits down-count input when the counter value reaches 0". do. In other words, this counter is configured to count up and down between "0" and "31".It is easier to use if the tracking delay amount is set to the middle in the standard state during playback, and V
When manufacturing the TR, it is necessary to be able to set the intermediate value immediately due to various adjustments, so the counter (3) uses a signal from the initial setting circuit (4) to set the intermediate value to the reference position, "15".
) can be preset.

The initial setting circuit (4) operates in the following cases.

B. If one source is input to the VTR, there will be six, and if a cassette tape is loaded or unloaded. C. Although not shown, this is a case where the reset circuit is activated.

The initial setting circuit 4) has an important role and allows the standard tracking position (reference position) to be easily set.
It is possible to save time during inspection at the manufacturing stage of VTRs.

The operation is as follows.

The counter <3) is set to "15" by the initial setting circuit (4).

When preset to , the output (bl) to (b4) is 1H''
level, and (b5) becomes "L" level. The analog switches (Sl) to (S5) are configured to close when the outputs b1 to b5 are at H level. For this reason, the analog switches (Sl) to (S4) close and the analog switch (S5
) opens, so the resistor (R5) acts as a time constant.
The combined resistance is (R5)+(7). For convenience of explanation, we will proceed without the resistor (7), and the tracking delay time will be [resistance (R5)].
) x value of capacitor (6) 1 second.

Next, when the up/down switches (1) and (2) are operated to raise or lower the counter (3), the output (bl
) to (b5) become 'H°゛ or "L" level depending on the content, so the series combined resistance value of resistors (R1) to (R5) that are not short-circuited by analog switches (Sl) to (35>) becomes the resistance component of the time constant.The system is such that the maximum resistance value is reached when the counter is "0", and the amount of delay is also the maximum.

Next, I will explain the first ward. FIG. 1 shows an example in which the circuit shown in FIG. 2 is incorporated into an actual VTR, and two counters (3a)<3b) are provided for slow playback and normal playback. Also, the mono multi is also 2 (8a> (ab) @).

The playback switch (11) and slow switch (12) are VT
This is the R operation switch. OR gate (13), (14
) is the up signal (34) from the remote control data (31).
>, input the down signal (35). OR gate (15
) and (16) input the reproduction signal <36) from the remote control data (31) and the slow signal (37).

(17) is a system controller (hereinafter referred to as system controller), which uses the reproduction signal from the OR gate (15) to
While setting the TR to the playback mode, the playback mode signal (Fl
) to enable tracking adjustment for normal playback. Further, the sysfun (17) puts the VTR in slow mode using the slow signal from the OR gate (16), outputs the slow mode signal (F2), and enables tracking adjustment for slow playback. Incidentally, this system controller (17) also receives a pause signal, fast forward number 18, stop signal, etc. to control the VTR, but these are not shown in the figure.

Limiter circuit (19) with playback mode signal (F 1 )
conducts and transmits the amplifier down signal to the normal reproduction counter (3a), whose output (23) passes through the output switching circuit (21), becomes the output (25), and outputs the D-R conversion circuit (
5) and is converted into a resistance value. In addition, the changeover switch (22) closes 5c-3a and inputs to the normal playback monomulti (8a), so as a result, the counter (3)
The tracking delay time will be determined by the contents of .

When the slow mode signal (F2) is generated, the limiter (20) becomes conductive, the slow counter (3b) is selected and becomes the output (24), and the output switching circuit (21)
The signal passes through the D-R conversion circuit (5) and is converted into a resistance value.The switch (22) between 5c and 3b is closed and input to the monomulti (8b) for intermittent slow playback.

The contents of the counters (3a) and (3b) can only be changed by the amplifier/down signal, except that they are preset to the intermediate value "15" by the initial setting circuit (4), so they are used for temporary tracking adjustment. Also, since the slow counter (3b) operates and the normal playback counter (3a) retains its contents, the previous tracking state can be reproduced even when the next normal playback is performed.

Next, we will discuss remote control operations.

Reference numeral (33) is an advance control device, and this part has push buttons necessary for operating the VTR as well as buttons for tracking adjustment, which are used for up-counting and down-counting, respectively.

The transmission system uses a pulse hood modulation method, which is well known in the art, but is not particularly limited to this method. After being amplified by an infrared light receiving section (32), it is decoded by a decoder circuit (31) and a necessary signal is output.

Next, a tracking display device, which is the gist of the present invention, will be described.

(41) is a microcomputer, and (42) is a TV screen character generation circuit, which has the function of creating a text information video signal (47) according to the content such as characters and figures to be displayed.
(43) is a synchronization separation circuit that converts the composite video signal (46) into horizontal synchronization (HS) and vertical synchronization (VS).
(44) is the original video signal (46
) and the text information video signal (47>) to produce a text multiplexed video signal (45).

In addition, there is a simple way to project characters and figures on the TV screen.
Many have been published. Further, since the character generation circuit is sold as an LSI, its explanation will be omitted.

The output (25) of the counter is input to the microcomputer (41). Also, although not shown in the figure, an OR gate (
13) The signal in (14) is input as the display start signal for tracking adjustment.

Usually, tracking information is not displayed on the TV screen. Decoder (31) or up/down switch (1)
, (2) gives an up/down signal, the microcontroller (4)
1) detects this and starts displaying information on the TV screen as a tracking adjustment start signal.

As shown in Figure 5, the display shows the text "TRACK I NG" (71) to indicate which operation is being performed, and a mark to show the range (72) that can be adjusted for tracking B to indicate its direction. Take out (73) and 74) to the left and right.

Next, the content of the counter (25) is calculated and a mark (75) indicating its position is displayed. These operations are performed quickly.

Since the mark (75) moves left and right according to the contents of the counter, its position can be sequentially indicated by performing tracking adjustment.

Also, if this display is constantly displayed on the TV screen, it will be an eyesore, so in this invention, if the input signal to the counter does not continue for about 5 seconds or more, the microcomputer (41 ).

As described above, in the present invention, the contents of the counters (3a) and (3b) are communicated to the user by the marks (75). Therefore, when the user operates the up/down switches (1) and (2) to perform tracking adjustment, the VTR is set to normal playback mode and first all position marks (75) within the range (72) are
move. At this time, the user may mark the mark (
75) Memorize the position. Then, after the mark 75) has been moved to all positions within this range (72),
The tracking adjustment during normal playback is completed by moving the mark 75) to the best position that has been memorized.

Next, set the VTR to slow playback mode and perform the same operation to perform tracking mt during slow playback. At this time, "Slow TRACK I NG" will be displayed on the TV screen.
is displayed.

In the embodiment shown in FIG. 1, the limiters (19) and (20) set the upper limit of the counters (3a) and (3b) to "31" and the lower limit to 0'.
The content of may change cyclically, such as "On→"31" or 31"→"O."In this case, the up/down switches (1) and (2) may change only on one of them. Tracking adjustments can be made.

In addition, in the above embodiment, the delay time is ±10 milliseconds 33.
Although it was possible to vary the time by 3, it may be made to vary by, for example, 3 milliseconds.

In addition, in the above embodiment, a counter (3a>(3) is displayed on the TV screen.
Although the value b) (corresponding to the amount of tracking deviation) is displayed, this may be displayed on, for example, an audio level meter of a VTR.

Furthermore, the playback envelope output may also be displayed.

(G) Effects of the Invention As described above, according to the present invention, the user can once change the content of counts (3a) and (3b) over the entire variable range, and at this time, the reproduction screen is the best. If you remember where to go, you can quickly adjust the tracking.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention. FIG. 2 is a diagram showing the tracking delay section, and FIG. 3 is a diagram showing the display state of the TV screen. FIG. 4 is a diagram showing an example of a conventional tracking servo, and FIG. 5 is a diagram showing a conventional tracking delay section. (bl) to (b5)...binary output delay time setting signal), (3a)...counter for normal playback (storage means), (
8a)...Monomulti (delay means), (1)...Switch for count up (adjustment means), (2)...Switch for countdown (adjustment means), (44)...
Mixing circuit (display means), (23) (25)...output (
delay time setting signal).

Claims (1)

[Claims] (1) Tracking servo is performed by comparing the phase of the playback control signal from the video tape and the reference signal, and
In a video tape player that performs tracking adjustment by varying the delay time of the playback control signal or the reference signal, the videotape player comprises: a storage means storing a delay time setting signal for determining the delay time; and a storage means storing a delay time setting signal for determining the delay time; delay means for delaying the playback control signal based on; adjustment means for increasing and/or decreasing the value of the delay time setting signal stored in the storage means; and adjusting means for displaying the value of the delay time setting signal. A videotape player comprising: a display means.