SU1095448A1 - Device for protecting crt against burn-through - Google Patents

Abstract

A DEVICE FOR PROTECTING THE ELECTRON-BEAM TUBE FROM A BURN, containing a series-connected clock generator and an AND element, a trigger and a character generator, characterized in that, in order to improve speed, two static registers, two comparison blocks, the OR element and an the counting input of which is connected to the output of the element And, the output is connected to the input of the installation in “1 flip-flop, a. the installation input in "O is combined with the installation input in" About the trigger and with the second input ele1) 1enta AND is connected to the output of the OR element, two inputs of which are connected respectively to the outputs of the corresponding comparison blocks, the first input of each of which is connected to the corresponding output of the character generator directly , a second input is through a static register whose recording input is connected to the output of a clock generator.

Description

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10 The invention relates to radio information display installations. The invention can be used in indicator channels containing cathode ray tubes (CRT). A device for protecting a cathode ray tube from a burn-through, containing the series-connected element I, the amplifier and the CRT 1, is known. The disadvantages of this device are the large inertia due to the presence of capacitors and the narrow range of variation of the velocity vector. The closest to the invention in its technical essence is a device for protecting a CRT from burning, containing a comparator, the first input of which is connected to the device input directly, the second input is connected through serially connected sampler and peak detector, and the output is connected through element I to the installation input "1 flip-flop, the output of which is connected to the control input of the switch, the first input of which is connected to the output of the block voltage source, the second input is the TV signal input, and the output The input of the sampling controller is connected to the first output of the clock generator, the second output of which is connected to the second input of the AND element, and the input is connected to the input of the setting “On the trigger,” and also the character generator 2. However, the known device with a linearly increasing deflection voltage of a CRT and is unable to function normally when using a deflection voltage of arbitrary shape. In addition, the use of a sync pulse trigger for resetting, in the event of an accidental failure of a device, leads to loss of information during the remaining part of the sweep period. The purpose of the invention is to increase speed. The goal is achieved by the fact that two static registers, two comparison blocks, an OR element and a counter, the counting input of which is connected to the output of the And element, are entered into the CRT protection device against a burn-through, containing a series-connected clock generator and an AND element, a trigger and a character generator. the output is connected to the installation input at “1 flip-flop”, and the installation input at “O” is combined with the installation input at “O flip-flop” and with the second input of the AND element and connected to the OR element stroke, whose two inputs are connected respectively to the outputs with The corresponding comparison blocks, the first input of each of which is connected to the corresponding output of the character generator directly, and the second input through a static register, the entry of which 1 82 is connected to the output of the clock frequency generator. The drawing shows a structural electrical circuit for protecting the CRT from burning. The device contains character generator 1, two static registers 2 and 3, two blocks 4 and 5 of comparison (horizontal and vertical deviation channels, respectively), element 6 OR, clock frequency generator 7, element 8 AND, counter 9 and trigger 10. The device works as follows in a way. During normal operation of the device, the velocity vector is different from zero, i.e., the coordinates of the beam are constantly changing. Current coordinates and coordinates, periodically recorded in both static registers 2 and 3, are different from each other. At the same time, at the output of at least one of the 4 or 5 comparison units there will be a logical unit, which, arriving at the input of element 6 OR, forms at its output a logical zero, which locks the element 8 AND, zeroed counter 9 and trigger 10. Logical unit removed from the zero arm of the trigger 10, is applied to the control electrode of the CRT and allows the beam to glow. In case of malfunction of the equipment for the formation of the sign information causing the stop of the beam, its coordinates, periodically recorded in both static registers 2 and 3, are equal to the current coordinates. In this case, logical zeros are formed at the outputs of blocks 4 and 5 of the comparison, at the output of element 6 OR there is a logical unit that removes the resetting of counter 9 and flip-flops 10. Element 8 AND opens, and pulses are received from the clock generator 7 at the counting input of counter 9. After a time equal to the period of the clock frequency multiplied by the digit of the counter 9, a logical ' I is formed at its output, which sets the trigger 10 into one state. Logical " 0 " formed by trigger 10, is applied to the control electrode of the CRT and locks it. The CRT protection device against burn-through allows the user to change the counter size any time from the moment the beam stops to the protection device, and using a different number of high-order bits from the output of the character generator 1 to the inputs of comparison units 4 and 5 and the inputs of static registers 2 and 3 , it is possible to set any value of the velocity vector of the deflection of a CRT beam at which the protection is triggered. In addition, the absence of inertial elements in the device makes it possible to avoid loss of the displayed information when the device is operating. Since the signals required

For operation of the device, taken directly from the output of symbol generator 1, shunt resistors connected in series to the coils of the deflecting system of a CRT are not needed. This reduces the inertia of the latter and increases the speed of the device as a whole.

The amount of burn-through of the phosphor in the CRT decreased by 80%, and the time required to turn on the beam after the device triggered decreased by 60%. The device is assembled on integrated circuits, occupies a small volume and consumes insignificant power, and with the above advantages it expands the scope of its application and allows to connect with a wide class of digital devices.

Claims (1)

DEVICE FOR PROTECTING AN ELECTRON BEAM TUBE FROM BURNING, containing a clock generator and an element And, a trigger and an oscillator, characterized in that, in order to improve performance, two static registers, two comparison blocks, an OR element and a counter are introduced into it, the counting input of which is connected to the output of the And element, the output is connected to the input of the installation in “1” of the trigger, a. the installation input at “0” is combined with the installation input at “0” of the trigger and the second input of the AND element and is connected to the output of the OR element, the two inputs of which are connected respectively to the outputs of the respective comparison units, the first input of each of which is connected directly to the corresponding output of the character generator and the second input is through a static register, the recording input of which is connected to the output of the clock generator. >