JPS5853057A - Automatic measuring device for dynamic characteristics for stylus cartridge - Google Patents

Abstract

PURPOSE:To reduce and automize a measuring time, by changing a guide groove jump driving force per once through the measurement control of a microcomputer, and quickly making a stylus arrive near a minimum or maximum saturation groove. CONSTITUTION:An FF27 is reset with an output of a clock generator 25 and a compartor 26, and the pulse width of a pulse applied to kicker coils 2-1, 2-2 can arbitrarily be controlled in response to a data loaded to the comparator 26. The data to be loaded to the comparator 26 is changed with a program stored in an ROM of a CPU21, and the pulse width of a pulse is sufficiently taken larger until a stylus 1 reaches the vicinity of a minimum saturation groove of a video disc 4 from a neutral position and after reaching the minimum saturation groove until reaching the vicinity of the maximum saturation groove, and the pulse width is sufficiently taken smaller in other cases.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that automatically changes the dynamic characteristics of a stylus cartridge in a short time in a capacitance conversion type video disc player using a guide groove.

The style 2 cartridge of a video disc player (hereinafter simply referred to as VDP) has a certain level of hemorrhoid life, and must be replaced with a new cartridge at a specified time during use. Since it is undesirable for the characteristics of the stylus cartridges to change, it is necessary that the characteristics of the stylus cartridges be sufficiently matched, that is, that they be fully compatible.

Therefore, in order to obtain a stylus cartridge with such compatibility, it is necessary to quantitatively evaluate various characteristics.One of the characteristics is that when the VDP pickup arp stops feeding, the stylus of the cartridge There are so-called dynamic characteristics of a stylus cartridge that indicate to what extent it can follow the guide groove of a video disc (hereinafter simply referred to as VD) and perform F-race.

Conventionally, as a method to accurately evaluate this dynamic characteristic by grasping the capacity, a capacitance conversion type VDP using a guide groove, for example, a capacitive mechanism equipped in a VDP called a CIItD type, has been used. The following method was proposed.

That is, first, prepare a VDP for leakage current, and place the stylus cartridge to be measured on its pickup arm (hereinafter referred to as
It is installed in a PU (simply referred to as a PU) to play back video signals from a VD.

Next, in this state, the feeding of Pv is stopped, and a pulse current of -9 pulse width is sequentially supplied to the driving coil of the kicker mechanism at a rate of once per vertical interval while the reproduced image is being reproduced. , the stylus is sequentially moved from the guide groove at the neutral point position toward the outer center of the VD. Then, the field groove number when the reproduced image becomes a still image is taken from the reproduced video signal and saved. Next, the polarity of the pulse current is reversed, the stylus is sequentially jumped from that position in the VD guide groove toward the inner shoulder, and the field groove number when the monitor image becomes a still image is read and memorized. do.

Then, the field groove number when the monitor image becomes a still image in the outer circumferential direction of the VD that was originally stored, and the field groove number when the monitor image becomes a still image in the inner circumferential direction of the VD that has just been memorized. Find the difference between the numbers and add VD to that number.
The reason for this is as follows. That is, the feed of the PU is stopped and the stylus of the cartridge is moved from its neutral point position to VD.
If you kick the stylus toward the outside direction or toward the inside shoulder, and the monitor image becomes a still image as you look back, it means that the stylus no longer jumps even though the kicker mechanism is activated. It shows. In other words, this indicates that the stylus can no longer be moved in the outward direction or in the inward circumferential direction.

Therefore, the dynamic characteristic range of the stylus cartridge is determined using this method. At this time, the guide groove with the smallest field groove number obtained in the outer direction of the VD is called the minimum saturation groove, and the inner groove is called the minimum saturation groove. The guide groove with the maximum field groove number obtained in the direction is called the maximum saturation groove.

However, in this conventional measuring force method, after the stylus cartridge for nada determination is attached to the PU, the feeding of the PU is stopped, the driving pulse is supplied to the kitsker coil, the monitor image is monitored, and the minimum saturation groove is reached. When reading the field groove number, reversing the polarity of the drive pulse, monitoring the monitor image,
Reading the field groove number when the maximum saturation groove is reached,
Since it is necessary to sequentially calculate the dynamic characteristic range by numerical calculation, the operation is complicated and MtF cannot be easily performed.

In addition, if the amount of jump per stylus guide groove jump by the kicker mechanism, which is repeated once in each vertical scanning period, is too large, the still image that appears on the monitor image when the minimum or maximum saturation groove is reached. cannot be obtained stably.

Therefore, in order to find the field groove numbers of the above-mentioned minimum and maximum saturation grooves, it is necessary to move the stylus from the neutral point position to the minimum saturation groove and then to the maximum saturation groove. There is also the drawback that the measurement time is quite long because the guide groove has to be jumped little by little many times.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic dynamic characteristic measuring device for a stylus cartridge which is easy to operate and can automatically obtain measurement results in a short period of time, while eliminating the drawbacks of the prior art described above.

In order to achieve this object, the present invention provides a miter computer that automatically executes operations necessary for measurement one after another according to its program, and also provides a driving force for each guide groove jump given to the stylus by a kicker mechanism. is characterized in that the stylus quickly reaches the vicinity of the minimum or maximum saturation groove by changing the groove.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an automatic curve measuring device for dynamic characteristics of a stylus cartridge according to the present invention will be described with reference to the drawings.

Figure 111 shows an example of a stylus cartridge used in a CID type VDP, where 1 represents the entire stylus cartridge, 1-1 is a stylus holder, 1-2 is a stylus, 2 is a kicker mechanism, 2 -1
．． 2-2 is a kitsuka coil, 2-3 is a kitsuka! 3 is the kicker drive circuit.

A pulse current is sent from the kicker drive circuit 3 to the kicker coil 2.
When supplied to -1.2-2, KITSUKA! Gnet 2-
An electromagnetic force acts on the kicker drive circuit 3, and the stylus 1-2 is kicked in a direction determined by the polarity of the pulse current supplied from the kicker drive circuit 3, thereby functioning to jump the guide groove of the VD. The amount of jump at this time can be arbitrarily controlled by the magnitude and pulse width of the supplied pulse current. Incidentally, this locking mechanism 2 is originally activated when the tracking of the stylus 1-2 becomes unstable or when the VD
This is provided for use when performing trick play operations on the P.

Next, FIG. 2 is a block diagram showing an embodiment of the present invention.
Stylus cartridge 1-, hard coil 2-1.
2-2. The kicker drive circuit 3 is the same as that shown in FIG.

In this figure 2, 4 is the VD% used for measurement, 5 is the turntable, 6 is the turntable drive motor, and 7 is the turntable.
is a PU feed motor mechanism, 8 is a video playback section, 9 is a tuner, 10 is a video demodulation circuit, 11 is a monitor display, 12 is a vertical synchronization signal output, 13 is a four-way output, 14
is video signal output, 15 is DAXI decoder, 16-1
9 is a peripheral interface adapter (referred to as PiA), 20 is an internal bus, and 21 is a central processing unit (C
22 is a random access memory (RAM)
), 23 is a character display, 24 is a monostable multivibrator (referred to as MMV), 25 is a four-way generator, 26 is a converter/<lator, 27 is a seven-stage lip-flop (referred to as FF), 28 is a current direction control circuit, 29 is an AND gate, and 30 is an MMV.

Note that IS-&) is a data signal line to which field groove number data is output, 15-(b) is a control line to which a signal indicating data latch completion is output, and 17-(a) is a DAX line.
A control line for outputting a control signal (chip select signal, etc.) for the I decoder 15, 18-hi) is a data signal line for outputting comparison data to the comparator 26, and 18-(b) is a signal for activating the AND gate 29. This is a control line that is output.

FIG. 3 shows the vertical blanking period 31 of the signals distributed to each VD40 guide groove, and the vertical synchronization signal 32 and the DAXI code 33 are recorded during this period 31. Which indicates that. And this D
AXI code and Lt, Dif+taA AuxlAia
ryInformcLtion: This is an abbreviation for LD, and the field groove number data tJ- is stored in this.

Therefore, when the VD4 is placed on the turntable 5 and the stylus cartridge 1 is set and operated, the vertical synchronization signal is output from the output 12 of the video demodulation circuit 10 of the video playback section 8, and the 42 DAXI code is output from the output 13. A 153 MHz clock for extracting each bit is output, and a video signal into which a DAX■ code is inserted is output from the output 14. At the same time Sennita Days Play 11
The regenerated Goken is displayed.

The DAXI decoder 16 decodes and latches the field groove number from the signal taken in from the video demodulation circuit 10, provides the data to the piA 16 from the signal line 15-(2), and indicates the completion of latching from the control line 15-(b). A signal is supplied to the PiA16. Then, this latch completion signal causes the P1 module 17 to pass through the control line x'l-(w).
Sends a signal to the DAXI decoder IS to perform chip selector.

CPtJ21 is equipped with a ROM that stores Bridalam, and P
Input field groove number data and latch completion signal through IA16.17, and interrupt signal from signal line 24-k;
At the same time, the pulse intensity data is applied to the comparator 26 via ptAlB, and the activation signal is applied to the AND gate 29.
The PU feed motor mechanism 7 is controlled to stop feeding the PU via the current control circuit 28, and the current direction control circuit 28 is controlled to control the polarity of the pulses supplied to the kicker coil 2-112-2.

Next, the operation of this embodiment will be explained.

When the start of the Ill operation is input, the CPU 21 immediately sends a signal to the PU feed motor mechanism 7 via the P motor 19 to stop feeding the PU, and also sends a signal to the current direction control circuit 28. Nakatsuka coil 2-1. Set the polarity of the pulse current to be supplied to Goose-2 so that it is kicked in the direction of the stylus 1-2 of cartridge 1 (Fig. 1) and the external station of 6tvn4.O Tweet, CPIJ! 1 is PiA18+7) control line 18-
A signal is applied to AND gate 29 via (b) to enable it, and at the same time, comparison data is provided to comparator 26 via signal 1118-&).

On the other hand, the output of the MMV 30 is supplied to the other input of the AND gate 29, and this MMV 30 is triggered by the vertical synchronization signal supplied from the output 12 of the video demodulation circuit 10, Therefore, as shown at time 34 in FIG. 3, the output of this MMV 30 is delayed by the time TI from the vertical synchronization signal 32, and is generated once every vertical period. It will be included every time.

As a result, the FF 27 is set at time 34 in Figure 14 (c), and then reset at time 35 when the signal is supplied from the comparator 26, and the output Q is as shown in Figure 14 (c). The pulse 36 will be obtained at the same timing. FIG. , the same figure (c) shows the output signal of the VMV3G ◇ Since this pulse 36 is supplied to the kicker drive circuit 3 via the current direction control circuit 28, the CPU 21
To! Once the PiA18f)l[111118-(Antgame via ml) 29 is activated, the kitker coil 2-1.2- is activated continuously once every vertical shoulder phase from then on.
A pulse current is supplied to 2, and after the PU stops feeding, the stylus 1-2, which was near the neutral point position, is sequentially moved in the direction of the outer dove of VD4 by a jump amount determined by a pulse width T of 360 VD.
40 Jumping the guide groove. In addition, at this time, MM
The reason why the delay time T is given to V3Q is to remove the jump timing of the guide groove by the stylus 1-2 from the vertical blanking period 31 and to ensure the reading of the field groove number.

On the other hand, in parallel with this, this pulse 36 is supplied from the output of the FF 27 to the MMV 24, is waveform-shaped, becomes a predetermined interrupt pulse, and is input to the P1 module 17 from the signal line 24-P. Therefore, the CPU 21 loads the field groove number data latched by the D/^XI decoder 15 into the RAM 22 before and after this interrupt pulse, compares them, and monitors whether the same field groove number appears. are doing.

In this way, the pulse 36 is activated a predetermined number of times.
When the stylus 1-2 reaches the minimum saturation groove, the CPU 21 stores the groove number as the minimum groove number and determines whether the field groove numbers read out around pulse 360 are the same. , at that point it sends a signal to the current direction control circuit 28 via the P1 block 19 and the pulse 36 being supplied to the kicker coil 2-1.2-2.
Reverse the polarity of

Therefore, from this point on, the stylus 1-2 begins to jump the guide groove toward the inner station of VD4, and after jumping a predetermined number of times, it reaches the maximum saturation groove, and then pulses 36 The field groove numbers taken into the RAM 22 are the same before and after.

At step 9, the CPU 21 stores the field groove number at this time as the maximum saturation groove number. Then, the vicinity of the minimum saturated groove, which has already been memorized, is subtracted from the maximum saturated groove number, and the dynamic characteristic range is calculated by multiplying it by the groove pitch of VD4, and the dynamic characteristic range is displayed on the display 23 or printed out as necessary. I do things.

Therefore, dynamic characteristics can be automatically measured simply by attaching the stylus cartridge 1 and starting the apparatus.

Incidentally, the above description has been made assuming that the pulse width T of the pulse 36 given to the kicker coil 2-1, 2-2 is constant. Therefore, at this time, as already explained, since it is not possible to increase the amount of jump per jump by changing the pulse width of the pulse 36, the stylus 1-2 is moved from its neutral point position to the minimum saturation. The pulse 36 must be supplied at least 900 times until the measurement is completed, and the measurement takes a long time. It becomes k.

Therefore, in the above-mentioned embodiment, the trigger generator 25 and the comparator 26 are provided, and the FF 27 wo!
j is set so that the pulse width T of the pulse 36 can be arbitrarily controlled according to the data loaded into the comparator 26. Then, the data to be loaded into the fan plater 26 is changed by a program stored in the ROM of the CPU 21, and the stylus 1-2 is changed from the neutral point position until it reaches the vicinity of the minimum saturation groove, and after it reaches the minimum saturation groove. The pulse width (9) of the pulse 36 is made sufficiently large during the period until reaching the vicinity of the maximum saturation groove, and the pulse width (9) is made sufficiently small at other times.

As a result, the stylus 1-2 moves quickly from the neutral point position to the vicinity of the minimum saturation groove and from the minimum saturation groove to the vicinity of the maximum saturation groove with a large jump amount by pulses with a sufficiently large pulse width. Since the guide grooves are jumped, the time required to reach the minimum and maximum saturation grooves is sufficiently shortened.
Moreover, when the minimum and maximum saturation grooves are reached, the amount of jump is sufficiently small, so the reproduction of the video signal near the saturation groove becomes unstable, making it difficult to detect that the minimum or maximum saturation grooves have been reached. This will be explained with reference to FIG. 5.

In the figure, the characteristic curve 40 is the Kitzker coil 2-1.2-
The pulse width T of the pulse 36 supplied to 2.

is constant, and in order to stably read the video signal near the saturation groove, the pulse width T cannot be made too large. It takes a long time to reach the vicinity of the large saturation groove from the minimum saturation groove.

On the other hand, the characteristic curve 41 is obtained by loading data into the comparator 26 and changing the pulse width of the pulse 36 supplied to the kicker coil 2-1, 2-2, from the neutral point position to the vicinity of the minimum saturation groove. It can be seen that the moving time (number of jumps) of the stylus 1-2 from the minimum saturation groove to the vicinity of the maximum saturation groove is extremely short.

Furthermore, regarding the value of the pulse width Tt of this pulse 36,
Measure several stylus cartridges with average characteristics in advance, find a pulse width that can shorten the measurement time sufficiently, and obtain stable and accurate measurement results, and set it in the program of the CPU 21. Just do it.

As explained above, according to the present invention, the dynamic characteristics of the VDP stylus cartridge can be measured stably and accurately in a short time, thereby eliminating the drawbacks of the conventional technology and improving the quality control and performance of the stylus cartridge. A useful automatic measuring device for dynamic properties can be provided.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of a stylus cartridge for a video disc player equipped with a kicker mechanism, FIG. 2 is a block diagram showing an example of an automatic measuring device for dynamic characteristics of a stylus cartridge according to the present invention, and FIG. An explanatory diagram showing the contents of a signal recorded on a video disk per revolution, Figures 4 (a) to (c) are time charts for explaining operation 1 of the embodiment shown in the wcz diagram, and Figure 5 The figure is also a characteristic curve diagram to clarify the effect. l...Stylus cartridge, 2...
・Kitsuka mechanism, 3...Kitsuka drive circuit, 8
...Video playback section, 15...DAXI
Decoder, 25... Clock generator, 26...
...Comparator, Figure 1

Claims (1)

[Claims] For video disc players that have a kicker mechanism that allows the stylus of the cartridge to jump arbitrarily between the guide grooves of the disc, and that evaluates the dynamic characteristics of the stylus cartridge based on the range in which the stylus guide groove can jump from the neutral point position. In a dynamic characteristic measuring device for a stylus cartridge, there is provided a drive pulse generating means for supplying a drive pulse of an arbitrary pulse width to the above-mentioned kicker mechanism every time a reproduction video signal is directly scanned, and a field number of the reproduction video signal. A miter combinator is provided for detecting and sequentially comparing the values, and a miter combinator for controlling these means to automatically carry out measurement operations. An automatic measuring device for dynamic characteristics of a stylus cartridge, characterized in that it is configured to be able to measure dynamic characteristics in a short time by supplying changing drive pulses to the kicker mechanism.