FI67984B - SLAECKNINGSKRETS - Google Patents

Description

67984

Shut down, iri

This invention relates to an extinguishing circuit for use in a record player comprising a sensor device for reproducing a frequency modulated carrier having a particular frequency band from a disc in accordance with a combined video signal when the needle device is in the repeat position, and a frequency demulating device to said particular frequency band, and means for processing the demodulated signal output of the frequency demodulation device to generate a combined video output signal 15.

U.S. Patent 3,842,194 to Jon K. Clemens, issued October 15, 1974, discloses a video disc system for recording and playback in which recorded information occurs in the form of geometric variations at the bottom of a sprimal groove on the surface of a disc substrate coated with an electrically conductive coating and wherein the dielectric layer is located on top of the conductive coating. A repeat needle including a conductive electrode attached to the insulating bracket is placed in the groove of the 25 plates. This needle is supported by a support arm mounted on a housing portion which is moved radially (relative to the rotating disk plate on which the disk is placed) to facilitate successive rotations of the disk in the groove with the needle position substantially constant. This needle electrode cooperates with the coating of the plate, forming a variable capacitance when the plate is rotated according to the geometric variations of the bottom of the groove as they pass under the needle electrode. Suitable circuits connected to the needle electrode convert the capacitance variations into electrical signal variations representing the recorded information.

67984

In the preferred form of the capacitive video disc system described above, the recorded image information includes a certain carrier frequency modulated according to the combined video signals and takes the form of successive variations in the depth of the groove bottom between the maximum and minimum depths. According to a particular solution described in U.S. Patent No. 3,911,476 to Eugene O. Keizer, image information is most preferably associated with audio information including a second carrier 10 (substantially lower in frequency than the first mentioned carrier) frequency modulated according to its audio signals, occurring in the form of "duty cycle" modulation of groove depth variations.

In a player for video discs of the type described above, corresponding FM detectors with appropriate input filters are preferably installed so as to recover audio and video signals from the frequency modulated signals obtained when playing the disc.

With a video disc player of the type described above for capturing recorded video signals for displaying an image, there is a problem that may occur (if not compensated for) that the displayed image periodically interferes at random locations in the form of white and / or black dots and streaks. , which appear in addition to the relevant image information. These image defects may vary in length, thickness, and duration of visibility. Although they do not completely corrupt the image information, the intermittent occurrence of such image defects may be a significant distraction to the viewer.

An analysis of this problem has revealed that a number of different causes may lead to the formation of different, embarrassing image spots and streaks. Some of these reasons may be related to defects in the disc itself. Other reasons may be related to the conditions encountered during a particular play of a particular disc (e.g., the needle encounters 3,67984 different types of debris in different areas of the disc groove). Still other causes (e.g., scratches, notches, etc.) may be related to previous use or damage to the disc being played. Without further distinguishing the causes of image defects, it is clear that there are a number of different types of causes that lead to a significant lack of predictability of the problem and vary from disc to disc, from play to time, from track area to track area, etc.

U.S. Patent 4,001,496 describes a system 10 for effectively masking the effects of signal failures during video disc playback. In this arrangement, the detection of faults includes relying on the identification of situations in which the instantaneous input frequencies to the FM image detector of the player image fall outside the limits of the deviation range of the signal of the intended image FM-15. This fault detector output works to adjust the current information by replacing the line information of the preceding image. Because the information in successive image lines is generally redundant to mask the occurrence of a fault with the information in the preceding line, making it relatively invisible to the image viewer.

In video disc players of the type described above, there are a number of situations in which it may be desirable to prevent the input of signals to the outputs of the player due to the nature of the output of the sensor circuit of the support. Some of these situations may be related to transient or otherwise faulty sensor functions. Other situations may be related to various advantageous operating cases provided in the player for desired phenomena such as standby, start-up, search, shutdown, etc., but which do not involve the development of useful signals for the sensor circuits. To prevent output under the described conditions, it has previously been proposed to use the output of the deflection clock component separator in the video signal processing circuits in this player to determine the existence of situations suitable for turning off the player outputs, i.e. to monitor pulse is not present for a certain period of time and shutdown is terminated when the pacing pulses return.

5 One of the problems encountered in an extinguishing system based on monitoring the output of a synchronous signal separator is that in certain situations where maintenance of the extinguishing condition is desired, the input to the synchronous signal separator contains noise which is erroneously converted to a synchronous pulse. to end the situation.

The present invention is directed to an extinguishing system in which maintaining a desired extinguishing condition is made relatively immune to erroneous noise-induced terminations. In accordance with the principles of the present invention, the generation of the extinguishing signal is made dependent on devices that detect a deviation from the instantaneous frequency at the input of the FM detector of this player compared to a predetermined target carrier deviation range.

Instruments using a fault compensation system of the general type already described in the aforementioned U.S. Patent 4,001,496 already have such a fault detection device present in the fault detector Simena; under these conditions, the shutdown signal generator may be conveniently actuated based on the output of the fault detector. Most preferably, the output of the fault detector from which the extinguishing signal generator operates includes or is subjected to a "stretch" procedure as described in said patent publication, whereby the resulting fault detection pulse, once started, continues until a certain period of time has elapsed without the input frequency specified deviation range. The nature of the noise output 35 of the player's sensor circuits in the absence of usable signals is typically such that appropriate selection of "stretch" parameters 5 67984 ensures that a stretched fault detection pulse is maintained throughout the absence of a usable signal.

It is, of course, desirable that the extreme operation of shutting off the output does not occur, e.g., during those faults, whereby the fault compensation system as described above may provide effective fault covering. According to a further feature of the present invention, the initiation of the message signal does not occur as a result of the fault detection input 10 except and until the fault detection lasts for a certain period of time. This given period of time is most preferably long compared to the duration of the line, with the illustrative Example Selection being 50 milliseconds.

Although the aforementioned delay in turning off the operation 15 is desirable to avoid erroneous and / or premature shutdown during disc playback during disc playback failures, it presents a problem that when the needle is lifted from the disc for desirable player operations such as stopping, searching or shutting down 20, noise may occur. access the player's outputs for the duration of the delay period before turning off. This delay period is typically long enough to allow, for example, the repetition of an interfering audio frequency noise discharge. According to an additional feature of the present invention, this embarrassing phenomenon can be eliminated by further operating the shutdown signal generator based on the removal of the needle from its ringing position, whereby this additional response is not subject to a delay in operation. According to a particular embodiment of the present invention, where the removal of the needle from the feed position is controlled by a needle arm raising and lowering mechanism provided by the solenoid, additional input to the extinguishing signal generator is derived from these current control circuits of the needle solenoid.

In the video disc players described herein, the video signal processing system may include circuitry 67984 that requires a period of time to stabilize, which time follows the start of detection of the correct input signals before guaranteeing the development of displayable player output signals. mounted for jitter stabilization purposes and using a gate circuit that passes burst components of a chrominance signal, the signal being processed in a phase detector as described in U.S. Patent No. 10,872,497. It is an object of the present invention to provide an extinguishing circuit in which the moment of application is applied to video signal processing circuits. the above-mentioned moment of the burst start of the PLL system, as well as the start time of the timing-15 information controlling the development of the burst pulse, as a result of which the operation of the PLL system is not prevented by a shutdown and in which the return of the player to the non-shutdown state is delayed compared to the inputs to cause the shutdown to operate for a period of sufficient length (e.g. one second) 20 to allow stabilization of the PLL system.

These objects are realized in an extinguishing circuit of the preamble type of claim 1, characterized by player control means for optionally moving the sensor device out of the playback position, means connected to the player control means for initiating with respect to terminating the transfer of the sensor device from the playback position-30, means for using a shutdown signal to prevent the development of a combined video output signal.

Other advantages of the present invention will become apparent from the following detailed description with reference to the accompanying drawings, in which: Fig. 1 is a partially sectioned view of a portion of a video disc player with which the present invention may be practiced; Fig. 2 is a schematic and partially block diagram illustration. for a video disc player including a shutdown circuit according to an embodiment of the present invention, and Fig. 3 illustrates in a partially schematic and in part block diagram form a system that can be used to perform the functions of a player control circuit in connection with the player shown in Fig. 2.

FIG. A needle 11, the tip of which is placed in the groove of the plate, is connected 15 to one end of the detector arm 12. This detector arm 12, which in the case of illustration may be of the type disclosed in U.S. Pat. No. 3,956,581, is pivotally supported by a support (not shown) in the housing 9.

The housing part 9 is fixed to a lug 10 extending through a slot 8 in the motor part 7. Below the motor part 7 there is an apparatus (not shown) which optionally supplies the driving force to the housing 9 via the lug 10. In the illustrative case, the drive apparatus is of the form disclosed in U.S. Patent No. 3,870,320, which allows the following choices as functions: a) Radial forward operation (labeled "f" in the drawings) at a certain "playback" speed, thus dependent on the disk rotation speed; to allow subsequent successive turns of the needle on the plate with the needle in a substantially constant position, b) radial travel in the "f" direction of travel at a second "forward" speed greater than the "repeat" speed; and 35 c) radial drive in the return direction (marked "r" in the drawings); ) at a "retrieval search" speed comparable to a forward search speed.

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In addition, a rotor 15 is mounted in the housing 9, to which a hinge lever 14 is attached, a certain part of which extends below the sensor arm 12 at a point in the middle thereof. Rotation of the rotor 15 by a wire 16 attached thereto allows the articulation lever to move to the following positions: 1) a lowered position allowing the sensor arm 12 to be lowered to the call position where the needle tip protrudes through the opening 13 in the bottom of the housing 9 to such an extent that the needle 11 may in contact with the groove of the plate 4 and 2) a raised position where the needle is not in contact with the groove.

Figure 2 shows a circuit arrangement of a player which can be advantageously used in a video disc player which is in the form of Figure 1. In the arrangement of Figure 2, the recorded signal is reproduced during video disc playback by video disc detector circuits 21, which may be, for example, of the type described in U.S. Patent No. 3,872,240.

20 By way of illustration, the recording format of this disc is such that the reproduced signal includes: a) a frequency modulated image carrier whose instantaneous carrier frequency varies within a fixed range (e.g., 3.9 to 6.9 MHz) according to an amplitude combined with a color video signal that the signal is located in a certain frequency band (e.g. 0 ... 3 MHz) below the range and represents successive color images to be displayed; and b) a frequency modulated audio carrier whose instantaneous carrier frequency varies in a narrow band with a low frequency carrier value (e.g. 0.7 MHz) , which signal represents the desired portion of the sound associated with the image.

A bandpass filter 23, the passband of which includes a carrier range and associated sidebands, optionally passes a frequency modulated audio carrier signal to a limiter 25. The output of the limiter is input to an FM detector 27 to detect audio information stored in the FM detector 27. The output of the detector 27 is amplified by an amplifier 29 so as to generate an audio signal coming out of the player. When the signals of the player are to be fed to the antenna terminals of the television receiver, the output of the amplifier 29 may act as an input of audio information to the source equipment, as described, for example, in U.S. Pat. No. 3,775,555.

A bandpass filter 31, the passband of which includes 10 image carrier offset areas and associated sidebands, optionally passes frequency modulated image carrier components from the output of detector circuits 2.1 limited to 33. The output of this limiter is supplied by the 15 generating a fixed output pulse of amplitude, width and polarity as a result of each zero crossing of the limited FM input signal. The pulsed output from the zero crossing detector 35 is fed 20 to a low pass filter 37, the passband of which is substantially suitable for the band (e.g. 0 ... 3 MHz) in which the stored video signal information is located.

The zero crossing detector 35 and the low-pass filter 37 form a frequency modulation detector of the so-called pulse counter type, which provides an output in the form of a combined video signal corresponding to the modulation of the incoming FM signal. In the illustrative case, the video signal information recovered from the disc includes a combined color video signal encoded in the form of a "buried subcarrier" as disclosed in U.S. Patent No. 3,872,498.

For illustrative purposes, the following parameters may be assumed to illustrate the buried subcarrier shape of the recorded composite color video signal: 35 1) color subcarrier frequency (f ^) = 195/2 f ^, i.e., approximately 1.53 MHz when the line frequency (f ..) corresponds to the U.S. dard for color television broadcasts, 67984 2) chrominance signal: the sum of the corresponding quarterly subcarrier phases amplitude-modulated by a red and blue color difference signal (RY, B.-Y) with a bandwidth of 0 ... 509 kHz and a lower bandwidth (500 MHz) lower side band stored (and carrier attenuated), 3) luminance signal (Y) with a bandwidth of 0 ... 3 MHz, 4) color phase component: burst of oscillations at the buried subcarrier frequency (f ^) in the reference phase and 10 amplitudes in the "post-scan" of the horizontal quench. during (corresponding to the normal NTSC chromaticity component for all components except frequency).

Based on the output of the zero crossing detector 35, a fault detector 61 also operates, which in the event of a reset 15 may be of the type disclosed in the aforementioned U.S. Patent 4,001,496. The fault detection pulses generated by the fault detector 61 are fed via a pulse stretcher 62 control to a wave generator 67 which provides sig-20 signals for controlling the switching state of the electronic switching device 39. In this connection, reference may be made to U.S. Patent 3,909,518 for a detailed description of the operation of a pulse stretcher and a suitable device for implementing the functions of the generator 67 and the switch-25 device 39.

Alternatively, the function of the electronic switching device 39 is 1) to complete the signal path between the "normal" signal input switch terminal N and the switching device output switch terminal 0, or 2) to complete the signal path between the "replacement" signal input terminal S and the output switch terminal O. The switching between the respective "normal" and "replacement" states is controlled by the output of the switching control wave generator 67 35, which is fed to the input signal terminal P of the control signal in this switching device 39.

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The output switch terminal 0 of the switching device 39 is connected to the input switch terminal of the modulating signal of the amplitude modulator 41. The "normal" input signal of the switching device 39 (i.e., the signal applied to the switching terminal N, which is then transferred to the input switching terminal of the modulating signal of the modulator 41 during the normal operation of the video disc player) is the combined video signal output of the low-pass filter 37. The "replacement" input signal (i.e., the signal applied to the switch terminal S, which is transmitted from there to the input switch terminal of the modulating signal of the modulator 41 during fault masking, i.e., the "replacement" mode of operation of the player) is a delayed combined video signal obtained as described below.

The function of the amplitude modulator 41 is to modulate the amplitude of the carriers input from the voltage controlled oscillator 43 according to the signals obtained from the output switch terminal O of the switching device. The amplitude modulator 41 is most preferably of the once balanced type (balanced with respect to the modulating signal). The normal frequency (f) of the carriers-20 input from the oscillator 43 corresponds to the frequency (f,) of the buried subcarrier.

O D

and the sum of the desired subcarrier output frequency (f) and, in the case of illustration, corresponds to 325 f „or approximately 5.11 MHz (e.g. in the case where the desired subcarrier - 25 wave output frequency corresponds to the NTSC subcarrier frequency 455/2 f„, i.e. approximately 3.58 MHz). In the illustrative case, the oscillator 43 is a voltage controlled crystal oscillator as disclosed in U.S. Patent 3,965,482.

Most desirably, the frequency of the carriers 30 generated by the oscillator 43 varies around the aforementioned nominal frequency, corresponding to the "vibration" of the frequencies of the combined video signals that are reproduced during disc playback. For this purpose, the voltage-controlled oscillator 43 is connected to a control circuit in an arrangement which forms a phase-locked loop 35, as disclosed in the aforementioned U.S. Patent 3,872,497.

12 67984 In the video disc player control arrangement illustrated herein, the output frequency of the oscillator 43 is controlled by the output of a phase detector 49 which detects the phase of the color synchronous component obtained from the disc with the phase of the output of the comparator oscillator 5. The reference oscillator 48 operates at the desired subcarrier output frequency (fQ) and is most preferably of the crystal controlled type. The color synchronous component is fed from a burst mixer 47 which responds to the output of an amplitude modulator 41 fed through a suction filter 45. The suction filter 45 prevents the relatively high amplitude carrier component from passing to the output of the modulator.

Most preferably, the burst mixer 47 includes a bandpass filter circuit whose response is limited to frequencies in the chrominance output band around the subcarrier output frequency (fQ) 15. Controlled by appropriately timed line frequency gate pulses, the burst gate 47 optionally passes through the filtered output of the modulator 41, which occurs during the post-step interval of the color synchronous component. The output of the burst gate 47 includes periodic oscillation bursts 20 nominally located at the output frequency of the subcarrier, the synchronous bursts being located at the frequency of the lower sideband of the output of the modulator 41.

A closed loop formed just as described above keeps the output of the synchronous burst component modulator 25 in the lower sideband synchronous in frequency (and phase) with the very stable output of the reference oscillator 48. When there is vibration of the reproduced combined video signal that tends to cause deviations from such a synchronous situation, the control voltage output of the phase detector 49 develops a compensatory correction to the output frequency of the oscillator 43 to prevent such a deviation.

The amplitude-modulated carrier output of the modulator 41 is applied to the input of comb filter circuits 51, which in the illustrative case are of the type described in U.S. Patent Application 570,325. for input to a combined signal output shaping circuit 5 (consisting of an adder 57), b) a luminance signal component separated at the output switch terminal L, and c) a delayed combined video signal acting as a "replacement" signal input to the switch terminal S of the switching device 39.

The luminance signal provided at the switch terminal L is fed to an attenuation circuit 53 which provides a luminance component by means of high frequency attenuation suitably complementary to the pre-gain used for recording on the disc. The output of the attenuation circuit 53 is fed to the level locking circuit 55, which returns the DC component of the luminance signal. In the illustrative case, the level lock circuit 55 is of the keyed level lock type and is keyed by periodic, line frequency 20 keying pulses timed to coincide with the periodic reference amplitude intervals of the light density signal (e.g., during the occurrence of a horizontal clock peak).

The level-locked output of circuit 55 forms a luminance component input to adder 57, which adds such an input to the upper band of the chrominance component output at switch terminal C, outputing a combined Color Video signal in a form suitable for input to a color monitor. When such input is to be made to the antenna terminals of the receiver, the output of the adder 57 may act as a combined video signal input to the transmitter equipment, e.g. in the form disclosed in the aforementioned U.S. Patent 3,775,555.

The player of Figure 2 also includes a synchronous signal separator 58 disposed to operate based on the output of the attenuator circuit 53 and for separating the oscillation clock components from the signal component representing the image of the luminance comb filter output. The output of the clock signal separator 58 is fed to a level lock key pulse generator 59 to precisely schedule the generation of key pulses to be fed to the above keyed level lock circuit 55. with the output of modulator 41. The gate pulse output from the generator 60 provides a signal through-pass time slot to the discharge port 47 in the PLL system controlling the VCO oscillator 53. In this regard, reference may be made to U.S. Patent 4,057,826 entitled "Sync Responsive Systems for Video Disc Players" for illustrative purposes. performing the functions of separator 58 and generators 59 and 60.

In accordance with the principles of the present invention, the player of Figure 2 includes a shutdown control signal generator 70 that operates based on the output of a pulse stretcher 62. An illustrative circuit arrangement for the pulse stretcher 62 and generator 70 is schematically illustrated in Figure 2. As shown, the pulse stretcher 62 includes an NPN transistor having a collector connected to a positive voltage supply source and a base receiving positive direction fault detection pulses "d" out of print. Capacitor 64 is connected between the emitter of transistor 63 and a ground potential point. Capacitor 64 is bypassed on the signal-30 path, which consists of a series combination of a base emitter path in the NPN input transistor 72 of the resistor 71 and the generator 70. The additional bypass path past the capacitor 64 includes a resistor 65 and here an input circuit of the switch control wave generator 67 (not shown 35 schematically).

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When a fault detection pulse "d" is generated at the base of transistor 63, this transistor conducts and capacitor 64 is charged to a positive voltage, which causes transistor 72 to conduct current. When the fault detection pulse "d" 5 at the base of the transistor 63 ends, the transistor 63 turns off, but the transistor 72 continues to conduct current due to the charge maintained by the capacitor 64. Discharge of capacitor 64 is implemented along a path that includes a resistor 71 and a base emitter path of transistor 72 (as well as an additional bypass path consisting of resistor 65 and input circuit of generator 67). In the illustrative case, the discharge time constant is selected so that a time interval of approximately 3 microseconds must elapse after the end of the fault detection pulses (without the occurrence of a new fault detection 15 pulse) before the transistor 72 turns off.

The NPN transistor 74 is connected in its base to the collector of the transistor 72, from its emitter to the ground potential point, and from its collector through a series of resistors 75 and 76 to a positive voltage supply source. Resistor 73 20 is connected between the positive voltage supply source and the base of transistor 74, with transistor 74 normally biased to conduct. However, during the stretched fault detection pulse, the conduction state of transistor 72 keeps transistor 74 off.

Capacitor 77 is connected between the ground potential point and the connection point of resistors 75 and 76. Capacitor 77 is bypassed by a series combination of diode 78 and resistor 79, in addition to which the base emitter path of NPN transistor 80 is connected across resistor 79 so that base 30 of transistor 80 is connected to the cathode of diode 78. When transistor 74 is off, capacitor 77 is charged towards the voltage of the positive voltage supply source as the charging current passes through resistor 76. The charge time constant is selected so that the transistor 74 is turned off after a predetermined number of line time intervals (e.g., 50 milliseconds), whereby the voltage across the capacitor 77 becomes positive enough to bias the diode 77 and the transistor 80 to conduct current.

The collector of transistor 80 is connected to a positive voltage supply source through a series of resistors 81 and 82. Capacitor 83 is connected between the ground potential point and the connection point of resistors 81 and 82, in addition to which a series combination of resistors 84 and 85 is connected across resistor 82. The emitter of PNP transistor 86 is connected to a positive voltage supply, its base is connected to the connection point of resistors 84 and 85, and its collector is connected via resistor 87 to a negative voltage supply (bypassed by capacitance 88). The base of the NPN transistor 90 is connected through a resistor 89 to the collector of the transistor 86, its emitter is connected to a negative voltage terminal supply source, and its collector is connected through a resistor 91 to a positive voltage supply source.

If transistor 80 has not recently conducted current, the charging of capacitor 83 (via resistor 82 and resistor 84 and 85) is such as to prevent current from transistors 86 and 90 from conducting current. Under these conditions, the collector of transistor 90 is at a positive voltage. Resistant resistors 93 and 95 transmit this voltage as a supply voltage to a) the video signal output adder 25 connected to the shutdown input switch terminal SQ and b) the shutdown input switch terminal SQ 'in the audio channel limiter 25. information displayed.

However, each time the transistor 80 is made conductive, the capacitor 83 is quickly discharged, allowing the transistor 86 to turn on and forcing the transistor 90 to conduct current. The collector voltage 35 of the transistor drops the negative voltage to the input source, and transferring this voltage to the terminals SQ and SQ 'performs 67984 shutdown at the combined video signal output adder 57 and audio channel limiter 25, preventing access to video disk sensor circuits as audio and video signal outputs.

When transistor 72 turns off at the end of the stretched error pulse, transistor 74 begins to conduct again and capacitor 77 discharges sufficiently to turn off diode 78 and transistor 80. However, transistors 86 and 90 continue to conduct after transistor 80 turns off 10 until capacitor 83 is charged sufficiently to raise transistor 86. above the conductivity threshold potential of the stock. The transistors 86 and 90 are then switched off and the voltages to be applied are regenerated at the switch terminals SQ and SQ '. The charge time constant of capacitor 83 is selected so that the delay in turning off transistor 90 relative to turning off transistor 80 is long enough (e.g., one second) to allow a player circuit, such as a PLL system associated with VCO 43, to stabilize before the reproducible information reaches the player outputs. . It should be noted that the video shutdown signal input point (to the combined video signal adder 57) is located after the video signal processing circuit relative to the output points when adjusting the inputs to the burst mixer of this PLL system, as a result of which the desired system stabilization can occur during delayed shutdown.

Premature shutdown of the adder 57 (and restrictor 25) is substantially prevented in the system described above. The noise at the output at the output of the video circuit sensor circuits 21, if no usable signals are available, tends to maintain a stretched fault pulse output, whereby the generator 70 operates to maintain a shutdown condition for the audio and video outputs of the player.

It is not desirable for the player to be turned off 18 67984 each time a fault is detected in the detector 61. For faults encountered during disc playback of up to several lines in time interval, the player's fault compensation system (which uses the generator 67, the switching device 39 and other components) develops a very satisfactory fault masking phenomenon. For even longer faults, it should be preferred to continue the fault remediation, even if less than fully effective, rather than initiating shutdown due to the relatively long (e.g., one second) recovery time mentioned above, most preferably included in the shutdown control signal generator 70. the aforementioned 50 milliseconds are therefore suitably connected to the response of transistor 80 to turn off transistor 1574. Thus, the stretched fault pulse must withstand a considerable number (e.g., 800) of line time slots before the shutdown signal. is initiated.

However, as a result of the aforementioned delay in the response of the transistor 80 to turn off the transistor 74, there is a 20 delay in turning off when starting a player mode such as pause, search, or shutdown by removing the needle from the disc groove. The length of this delay is typically long enough to allow the embarrassing noise burst to be processed before extinguishing occurs. To avoid such a phenomenon, which is particularly embarrassing in terms of sound reproduction, the generator 70 is made to operate on the basis of an additional input obtained from the equipment involved in the placement of the needle.

The player arrangement of Fig. 2 is shown to include a solenoid-actuated player actuator 115 and a solenoid-actuated needle lowering device 119. A solenoid using a ring member to control the actuation of the player actuator 115 is schematically represented by a solenoid winding 113 while , the function of which controls the operation of the needle lowering apparatus 119 is schematically illustrated by a solenoid winding 117. Each of the windings 113 and 117 is connected between a positive voltage supply source and a collector of an NPN transistor 112. The emitter of transistor 112 is reconnected to the negative voltage supply source and the base of transistor 112 is connected to the output terminal PC of the player control circuits 111.

When the player control circuits 111 generate a voltage at the output switch terminal PC which biases the base emitter path of the transistor 112 in the line 10, current conduction occurs in the transistor 112, which lowers its clock voltage toward the negative supply voltage supply source voltage. Under these conditions, current flows through the solenoid windings 113 and 117 of a size sufficient to actuate the reproducing drive 115 and the needle lowering device 119. Consequently, referring to the illustrative structure in Figure 1, a) the rotor 15 and the articulated lever 14 begin to rotate downward turning in the needle arm 12 20 to a position allowing the groove of the plate to receive the tip of the needle 11; and b) the drive is actuated by the lug 10, providing radial forward movement of the housing portion 9 in the "f" direction at a substantially constant needle position.

Thus, during the normal "ringing" mode of operation of the illustrated player, when the position of the needle and the use of the housing portion are relevant for reproducing information stored in successive areas of the disc groove on the sensor circuits 21, the voltage 30 of the transistor 112 collector is substantially negative.

However, for other modes of operation of the player arrangement of Figure 2 (e.g., stop, search, etc.), the player control circuits 111 are arranged to supply an extinguishing voltage to the terminal PC of the switch-35, which stops conducting current to the transistor 112. When the transistor 112 is in a non-conductive state, the solenoid windings 113 and 117 no longer receive a current suitable for the operation of the player drive apparatus 115 and the needle lowering apparatus 119. Switching off these solenoids results in: 5 a) a rotor 15 in the opposite direction of rotation (Figure 1), which ensures that the needle current 12 is lifted up using the lever 14, removing the needle 11 from the plate groove, and b) the housing part 9 and lug 10 disengaging from the apparatus. radial-10 directional drive at normal ringing speed. In such conditions, when the position of the needle and the control of the housing part are not suitable for the sensor circuits 21 to display the recorded information, the voltage on the collector of the transistor 112 approaches the voltage of the positive voltage supply source.

The quench control signal generator 70 is operated based on the operating voltage on the collector of transistor 112 by connecting a series combination of resistor 120 and diode 121 between the collector of transistor 112 and the base of transistor 80. The polarity of this diode is oriented (with its cathode connected to the base of transistor 80) so that it is non-conductive during the "ring" mode of operation when transistor 112 conducts current.

Thus, during the "ring" mode of operation, the base of transistor 80 is isolated from transistor 112, and the control of transistor 80 depends on previously established situations related to charging capacitor 77. However, when the player is removed from the "ring" mode by generating a cut-off voltage at the switch terminal PC, a voltage rise across the transistor 30 collector biases the diode 121 and allows transistor 80 to be turned on immediately (if it has been in a non-conductive state before this time). to switch terminals SQ and 35 SQ '. Thus, it can be guaranteed that the lifting of the needle, which is effected by the control circuits 111 of the instruments, is associated with substantially immediate shutdown operation 21 67984 without having to wait for a fault indication of the delay time described above when charging capacitor 77.

Fig. 3 shows a partial and simplified view of a circuit arrangement which, in the case of illustration, can be used to perform some of the tasks performed by the control circuits 111 of the player of Fig. 2. Figure 3 shows a pair of AC inputs i and i1 connected to the input of the power supply 133 and on / off with the switch 131 set to the switch terminal "i". When the on / off switch 131 is closed, the power supply 133 receives the AC input and generates a positive DC voltage (output terminal labeled +20) and a negative DC voltage (output terminal terminal labeled -20).

Said power terminal 133 of the power supply 133 is connected to the second terminal of the resistor 136 by a cover lock switch 135 when the cover lock switch 135 is closed by closing the cover of the video disc player. The remaining switch terminal of the resistor 136 is connected to the input-input terminal "ring" of the down position switch 138 by switching 137 when the user of the player who wants to start the playback operation of the player closes the "ring" switch 137.

The lowering position switch 138 is, in the illustrative case, a single-pole two-position switch, where its position depends on the location of the motorized housing part 9 (Fig. 1). When the housing part 9 is detached from the disc plate 5 in its rest position, the position of the switch 138 (as illustrated by the solid line 30 in Fig. 3) is such that it connects the input of the input terminal of the switch 138 to the input of the apparatus 139. Thus, when the switches 131, 135 and 137 are all closed with the housing portion 9 in its rest position, a positive DC voltage is applied from the power supply 133 to the input of the dialing apparatus 139 via the switch 135, the resistor 136, the switch 137 and the switch 138.

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In the illustrating case, the call initiation apparatus 139 operates on the basis of the appearance of a positive DC input by switching on the motor drive to cause the disk 5 (Fig. 1) to rotate and 5 actuating the actuator for the housing part 9 previously mentioned call speed. When the movable housing part 9 arrives at a certain position which places the needle 11 on top of the outer layers of the plate groove containing the recorded information of this plate, the position switch 138 is turned to its second turning position (shown by a broken line in Fig. 3).

In the second inverted position of the switch 138, the input terminal of the switch 15 is connected via a series of resistors 141 and 143 to the base of the NPN transistor 145. The emitter of transistor 145 is connected to the terminal of power supply 133 which has a voltage of -20 by means of resistor 147 and the base of transistor 145 is connected to terminal of terminal -20 via resistor 144. A resistor 146 is connected between the collector of transistor 145 and the ground potential point.

When the switch 138 is in its first turning position, the transistor 145 is in a non-conductive state. Under such conditions, the emitter of the transistor 145 and the output switch terminal PC of the control circuit connected thereto are at the voltage of the negative voltage supply source. However, when the switch 138 is turned to its second position as the housing portion moves over the plate, a turn-on voltage is applied to the base of the transistor 145 +20 from the switch terminal 135, the switch 136, the switch 138, the switch 138 and the resistors 141 and 143. The resulting conduction state of transistor 145 thus causes a rise in the voltage of the output switch terminal PC per ground voltage. The effect of such a rise in the circuit of Figures 2 is to bring the transistor 112 into a conduction state resulting in the actuation of the ringing apparatus and the needle solenoids.

23 67 9 8 4

The simplified view of Fig. 3 does not show, for example, the devices mounted on the control circuits of the player to maintain the power of the disc motor when the switch 138 is in its second turning position. The simplified representation of Fig. 3 5 also does not show control circuits that provide such modes of operation of the player as stop or search. However, such additional circuitry may, in the illustrative case, include suitable components coupled to terminal D (at terminals 141 and 143 of resistors 10) to optionally prevent the development of a sufficient directional bias voltage across the base emitter path of transistor 145 to allow its conduction. When such additional circuitry is optionally enabled, the resulting transistor 145 is turned off by the transistor 112 from the arrangement of Figure 2, resulting in biasing the diode 121 in the line direction and initiating the shutdown operation as desired.

As an example, the following numeric values are shown for the circuit parameters of the schematic part 20 shown in Figure 2:

Resistance 65 2,200 ohms "71 33,000 ohms" 73 10,000 ohms "75 220 ohms 25" 76 100,000 ohms "79 15,000 ohms" 81 220 ohms "82 68,000 ohms" 84 68,000 ohms 30 "85 27,000 ohms" 87 68,000 ohms "89 15,000 ohms "91 2,700 ohms" 93,150,000 ohms 35 "95 10,000 ohms" 120 120,000 ohms 67984 24

Capacitor 64,470 picofarads "77 4.7 microfarads 83 10 microfarads" 88 0.1 microfarads 5 Diodes 78 and 121 types 1N914

Transistor 63 types 2N3904 "72,74,80,90 types MPSA20" 86 types MPSA70 "112 types MPSA06

Claims (3)

67984 A quenching circuit for use in a disc player comprising a sensor device for reproducing a frequency modulated carrier having a certain frequency band according to a combined video signal from a disk when the needle device is in the playback position, a frequency demodulation device (35) responsive to substantially to said 10 specific frequency bands, and means (51-57) for processing the demodulated output signal of the frequency demodulation device to generate a combined video output signal, characterized by player control means (111, 14, 15) for optionally moving the sensor device away from the playback position, is connected to the control means of the player for starting the generation of the shutdown signal from the start of the optional transfer of the sensor device from the repeat position by the control means of the player, the means (83) for delaying the termination of the shutdown signal with respect to deciding to move the sensor device from the repeat position, means (57) for using a shutdown signal to prevent the development of a combined video output signal. The apparatus of claim 1, wherein the combined video signal includes a deflection clock component, a color clock component, and image signal components comprising a luminance signal component having said particular frequency band and a chromaticity signal component sharing a portion of said particular frequency. here, and wherein the signal sensor comprises a needle supported by the sensor arm, characterized in that the player control means optionally includes energizable means (117, 119) for controlling the position of the sensor arm which the arm position control members, when energized, place in the repeater position, and that the signal processing means includes a first comb filter member (51) responsive to the demodulated output signal of the frequency demodulation device 26 67984 to generate a first comb-filtered signal output (L) including a deflection rate component and a luminance signal component for color synchronization. mponentin and värikkyyskomponen-5-acetate substantially in the absence of second kampasuodanelin (51) responsive to taajuusdemodulointilaitteen the demodulated output signal of the second comb filtered output signal (C) for generating said given frequency band above the frequency band and the output signal inclu-10 MPLIANCEWITH carried over from the color-stroke component and the chrominance frequency versions of the deflection stroke component and a luminance component, substantially, and summing means (57) responsive to the respective output signals of the first and second comb filter members to generate a combined video output signal, means (70) coupled to the arm position control means for generating a shutdown signal depending on the current signal of the arm position control means; (83) for delaying the termination of the generation of the extinguishing signal 20 relative to the power on of the position control means of the arm, and the means (57) to use a shutdown signal to prevent the development of a combined video output signal. The apparatus of claim 1, wherein the combined video signal includes a deflection synchronous component, a color synchronous component, and image signal components including a luminance signal component having said specific frequency band and a chromaticity signal component sharing a portion of said, certain frequency, said frequency. that the signal processing means comprises: a first comb filter member (51) responsive to the demodulated output signal of the frequency demodulation device for generating a first comb filtered output signal (L) 51 comprising reacting with the demodulated output signal of the frequency demodulator to generate a second comb-filtered output signal (C) for said frequency band above a certain frequency band, and the output signal includes the deviation of the color synchronous component and the chrominance component in the substantial absence of the synchronous component and the luminance component, and summing means (57) responsive to the respective output signals of the first and second comb filter elements for generating the combined output signal in order to disable them. 28 67984