SU1538277A1 - Line scanning device - Google Patents

Abstract

The invention relates to television. The purpose of the invention is to increase reliability while increasing the linearity of the sweep. In the line scanner, from the frequency pulses of the lines having the shape of a meander, Mr. 1, the sawtooth voltage forms a linearly increasing voltage supplied to Comparators 2 and 3. They form line frequency pulses, the phase of which depends on the threshold of their triggering. After amplification, these pulses are fed through matching transformers 9 and 10 to transistors 11 and 14, controlling the operation of two series-connected switches made up respectively by transistors 11 and 14, diodes 12 and 15, and reverse capacitors 13 and 16. Increased reliability is achieved by restoring imbalance when unbalancing the keys. To obtain the linearity of the sweep, the voltage supplied to the upper output of the deflection coil 20 through the correction capacitor 19 is summed with the voltage supplied to the lower output of the coil 20 through the linear amplifier 21, whose input receives a correction voltage proportional to the difference between the required and the actual deflection current values. 1 il.

Description

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The invention relates to television technology and can be used in scanning circuits of information display devices with an increased standard of decomposition.

The purpose of the invention is to increase reliability while increasing the linearity of the sweep.

The drawing shows a structural electrical circuit of the horizontal scanning device.

The horizontal scanner contains a generator 1 sawtooth voltage (GTP), the first 1 and second 2 comparators, the differential amplifier 4, the first 5 and second 6 storage capacitors, the first 7 and second 8 preamplifiers, the first 9 and second 10 matching trans, formators, the first transistor 11, the first diode 12, the first capacitor 13, reverse, the second transistor 14, the second diode 15, the second capacitor 16, reverse, choke 17, the source 18 of the supply voltage, the correction capacitor 19, the bias coil 20, the linear amplifier 21 l, and the first 22 and second 23 capacitive voltage dividers.

The line scanner operates as follows.

Frequency pulses of the rows, having the form of a meander, are fed to the input of GTP 1, the output of which produces a linearly increasing voltage supplied to the non-inverting inputs of the first 2 and second 3 comparators. Their inverting inputs receive a reference voltage generated at the outputs of the differential amplifier 4 and smoothed by the first 5 and second 6 storage capacitors. At the outputs of the first 2 and second 3 comparators, line frequency pulses are generated, the phase of which depends on the response threshold of comparators 2 and 3, which, in turn, is determined by the voltage at their non-inverting inputs.

The output pulses of comparators 2 and 3 after amplification by the first and second preamplifiers 7 and 8 through matching transformers 9 and 10 are fed to the bases of the first 11 and second 14 transistors, controlling the operation of two successively included keys formed by elements 11-1, respectively. To collector transis

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The torch 11 of the upper key is connected to a circuit consisting of a series-connected correction capacitor 19 and a deflecting coil 20. The keys are powered from the source 18 of the power supply through a choke 17.

The successive switching on of two keys makes it possible to significantly simplify the operation of their elements — transistors, diodes, and reverse capacitors. However, this raises the problem of leveling the time of locking the first 11 and second 14 transistors and, consequently, the reverse voltage pulses at their collector-emitter transitions,

Dunng. The problem is solved by introducing feedback that operates as follows. At equal values of the reverse voltage pulses, pulses of the same amplitude act on the first and second inputs of the differential amplifier (due to the fact that the division factor of the first capacitive voltage divider 22 is twice as high as the division factor of the second capacitor divider 23). In this case, respectively, the first 5 and second 6 storage capacitors form voltages of the same value, therefore, the duration and phase of the pulses at the output of the first 2 and second 3 comparators are also the same.

When the keys are unbalanced, for example, due to the time difference between switching off the first 1 and second 14 transistors, the amplitudes of the pulses at the inputs of the differential amplifier 4 and the voltage on the first and second memory capacitors are also different. This, in turn, leads to a change in the pulse duration at the outputs of the first 2 and second 3 comparators, so that the imbalance is restored.

In order to increase the linearity of the sweep, the voltage supplied to the upper output of the deflecting coil 20 through the correction capacitor 19 is summed with the voltage supplied to the lower output of the deflecting coil 20 through the linear amplifier 21, to the input of which a correction voltage arrives proportional to the difference between the required and actual deflection current values. The latter could be EFFECT, for example, using a current sensor in the form of a resistor connected in series to the deviation circuit.

Claims (1)

5 claims The line scanner device containing the first preamplifier, the output of which through the primary winding of the first matching transformer is connected to the power supply source, the secondary winding of the first matching transformer is connected to the first and second terminals of the first transistor, the emitter which is connected to the anode of the first diode and the first output of the first return capacitor, the second output of which is connected to the collector of the first transistor, to the cathode of the first diode, from the first The terminals of the throttles and the correction capacitor, the second output of which is connected to the first output of the deflector, the second output of the throttles is connected to the power supply source, as well as the linear amplifier whose input is the input voltage of the correction, 30 different that, in order to increase reliability while improving the linearity of the sweep, a second preamplifier, a second matching transformer, a second 35 transistor, a second diode, a second flyback capacitor, a sawtooth generator were introduced variable voltage, differential amplifier, two capacitive a voltage divider, two storage capacitors and two comparators, the outputs of which are connected respectively to the inputs of the first and second preamplifiers, the output of the second preamplifier is connected via the primary winding of the second matching transformer to the voltage source, the secondary winding of the second matching transformer is connected to the first and second terminals with the base and emitter of the second transistor, the emitter of which is connected to the common bus, with the anode of the second diode and with the first output of the second end A backstop sensor, the second output of which is connected to the cathode of the second diode, the collector of the second transistor and the emitter of the first transistor, the direct inputs of the first and second comparators are connected to the output of the sawtooth generator, the input of which is the input of line frequency pulses, and the inverting inputs of the first and second The second comparators are connected respectively to the second and first outputs of the differential amplifier and to the first terminals of the first and second storage capacitors, the second terminals of which are connected The first and second inputs of the differential amplifier are connected via the first and second capacitive voltage dividers with the collectors of the first and second transistors, respectively, and the second output of the deflection coil is connected to the output of the linear amplifier.