SU760483A1 - Device for compensating for pick-up tube raster variations - Google Patents

Description

The invention relates to radio engineering and can be used in television.

A device is known for compensating for a change in the raster of a transmitting television (TV) tube containing an optical unit located in front of the optical input of the transducer unit. a television tube, the first and second inputs of which are connected respectively to the output of the focus current generator and to a high-voltage power supply; the output of the transmitting television tube unit is connected to the input of the video amplifier, and to the third. and the fourth inputs of the transmitting television tube unit are respectively connected to the output of a digital-to-analog frame converter and the output of a digital-to-line horizontal converter, the input of each of which is connected respectively to the output of the frame scan counter and the output of the horizontal scan counter, to the input of which the clock generator is output m ·

However, the known device has a low accuracy of compensation of raster changes.

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The aim of the invention is to improve the accuracy of compensation for changes in raster ..

To do this, the inverter, the first, digital-to-analog converter and the first low-pass filter, as well as the second digital-to-analog converter and the second low-pass filter are serially connected to the known device to compensate for the raster of the transmitting TV tube, and the second digital-to-analog converter and the second low-pass filter are connected in series to to the first inputs of the first and second digital-to-analog converters, and the output of the first low-pass filter and the output of the second low-pass filter They are respectively connected to the second input of the line-to-analog digital converter and to the second input of the digital scanning frame converter, the output of the line scanning counter is connected to the second input of the first digital-analog converter, and the output of the frame scanning counter is connected to the second input of the second digital-analog converter, while the third input the inputs of the first and the second

760483

The south digital-to-analog converter is connected to the output of the inverter.

FIG. 1 shows the structural electrical circuit of the proposed device; 2 shows the signal form at various points in the circuit.

A device for compensating a raster change of the Transmitting TV tube contains an optical unit 1 located in front of the optical input of the unit 2 of the transmitting TV tube, a high-voltage power source 3, a focus current generator 4, a video amplifier 5, a digital-to-analog converter. (DAC). 6 frame scanning *, D / A 7 horizontal scanning, counters 8 and 9 of vertical and horizontal scanning, respectively, clock generator 10 ,. an inverter 11, first and second D / A converters 12 and 13, first and second low-pass filters (LPF) 14 and 15.

The device works as follows. ..... ·

The video signal from the output of video amplifier 5 is fed to the inputs of the negative reference voltage of the DAC 12 and 13, and the video signal inverted by the inverter 11 is connected to the inputs of the positive reference voltage. The bits that control the sign of the output voltage of the DAC 12 and 13 are connected to the higher bits of counters 9 and 8, and the amplitude control bits to the remaining bits. With such a connection, a pulse appears at the output of the DAC 12 and 13, which coincides in shape with the video pulse of the output of the video amplifier 5. The pulse has negative polarity (Fig. 2a, curve A), if the image of the luminous point is in the first half of the television raster along the corresponding coordinate , and positive polarity (fig. 26, curve B) - if in the second half; the amplitude of the signal increases linearly with the distance along the corresponding coordinate. images of luminous: point from the center of the television raster. Voltages from the outputs of LPF 14 and 15 (Fig. 2a, curve B and Fig. 2b, curve D ^ supplied to the inputs of the DAC b and 7, correct the television raster. In fact, the circuit of the video amplifier 5 - inverter 11 - DAC 12 and 13 - LPF 14 and 15 - D / A converter 7 and 6 - block 2 - video amplifier 5 is a feedback circuit, coupling along both X and Y coordinates to compensate for the change in the size of the television raster due to the Change in voltage on the electrodes of the transmitting TV tube of unit 2 as the signal amplitude increases LPF 14 and 15 simulate transient processes in the high-voltage circuit. supply point 3 *. ·····

The proposed device allows? - · em to increase the short-term stable1

TV raster and thereby improve the accuracy of measuring the coordinates of luminous sources.

Claims (1)

Claim A device to compensate for changes in the transmitting television tube raster, containing optical 10 unit located in front of the optical input of the transmitting television tube unit, the first and second inputs of which are connected respectively to the output of the focus current generator and 55 to a high-voltage power source, while the output of the transmitting television tube unit is connected to the input of the video amplifier, while the third and fourth inputs of the transmitting television tube unit are connected respectively. the output of the digital-to-analog converter of the frame sweep and the output of the digital-analogue transducer of the horizontal scan, the input of each of which is connected respectively to the output of the frame scan counter and the output of the horizontal scan counter, the input of which is connected to the output of the clock generator, which is , with In order to improve the accuracy of compensation of · raster changes, an inverter is introduced in series, the first digital-to-analog converter, the first low-pass filter, and 35 serially connected second digital-to-analog converter and \ second low pass filter, while the output of the video amplifier is connected respectively to the input of the inverter and to dd 'to the first inputs of the first and second digital-to-analog converters, and the output of the first low-pass filter and the output of the second low-pass filter ... that are connected respectively to. the second input of the digital-to-analog line scan converter and to the second input of the digital-analog frame-scan converter; the output of the horizontal scan counter is connected to the second input 50 of the first digital-to-analog converter, and the output of the frame scan counter is connected to the second input of the second digital-to-analog converter, and to the third inputs 55 of the first and second digital-to-analog converters are connected to the output of the inverter.