SU542212A1 - Graphic reading device - Google Patents

Description

A de-signal, then coming to the video loop and a 2, for amplification.

The video signal generated by the transmitting television tube 1 is a sequence of video stimuli, each of which corresponds to converting a single line of television image into an electrical signal,

From the output of video amplifier 2, the amplified video pulse is fed to the input of delay element 3, which delays the signal by a time equal to the duration of one line. At the same time, a video pulse is fed to the input of a spectrum analyzer 6, which performs a sequential spectral analysis of each line of the television image. At the output of the spectrum analyzer, a pulse signal is formed, which is the spectrum of the video pulse currently being analyzed, and the duration of the output signal is proportional to the width of the spectrum of the video pulse. The pulse signal from the output of the spectrum analyzer 6 is fed to the input of the demodulator 7, which converts the duration of the pulse signal to am or the output voltage.

As a result of the conversion, a signal is generated at the output of the demodulator 7, the amplitude of which is proportional to the width of the spectrum of the video pulse. The signal from the output of the demodulator 7 is fed to the control input of the frequency generator 8. The frequency of the oscillations generated by generator 8 is proportional to the amplitude of the control voltage applied to the offset input of the generator from the output of the demodulator 7 and is accordingly proportional to the width of the spectrum of the video pulse. The oscillations from the output of the generator 8 are fed to the amplitude limiting unit 9, which converts these oscillations into a sequence of pulses. The duration of the generated pulses is inversely proportional to the oscillation frequency. Thus, at the output of the amplitude limiting unit 9, a sequence of pulses is formed whose duration is inversely proportional to the width of the spectrum of the video pulse. The pulse sequence formed at the output of block 9 is fed to the second input of gating unit 4 and controls the gating of the video signal arriving at the first input of this block from the output of delay element 3. The delay element delays the video impulse during the formation of the sequence of gating pulses. By the time of arrival of the video impulse to the first input of block 4, a sequence of gating pulses arrives at its second input, the duration of which is inversely proportional to the width

video pulse spectrum. Gating unit 4 passes a sampled image of the line to the output. The sampling interval determined by the duration of the gating pulses corresponds to

the optimal sampling interval of a continuous signal in accordance with the sampling theorem. From the output of block 4, the discretized image of the line is fed to the interface block with the computational cleat 5, which performs coordination with the computer,

Each line of the television image is entered into the computer in a similar way. The introduction of new units has allowed the

to increase the accuracy of the device in 1.25 -1.4 times compared with the known devices.

Claims (2)

1.Patent of France No. 2153729.06 K 9/00, dated 04.O5.73 g, 2. The patent of England, No. 1264807, cl. G 4 D from 23.02.72, the (prototype).