SU123197A1 - The method of narrowing the spectrum of the television signal - Google Patents

Description

Methods are known for narrowing the spectrum of a television signal based on the transmission of quantized differences in luminance and coordinates of image elements, the brightness of which differs from the brightness of surrounding elements, using two groups of signals using memory devices for rewriting the message transfer rate. The disadvantages of such methods are their low noise immunity and the continuous accumulation of errors in the transmission process.

In the described method, these shortcomings are eliminated by the fact that the coordinates of the transmitted elements are determined not relative to the previous element, but relative to the beginning of the line, which eliminates the impact of the accumulation of errors along the line, and they are transmitted in the form of discrete numbers using pulse-code modulation, which increases the noise immunity of the system .

A flowchart illustrating the described method is shown in the drawing.

The signal from sensor 1 of the television signal, the sweeps of which are synchronized by the synchronizing generator 2, enters the conversion unit 3, in which one of the known methods produces a discrete unipolar difference image signal, quantized on the parameter op 11 en1 () with the number poBHCii. The signals received at the output of the block o are fed to the control pulse shaping unit 4 and the luminance signal recording and reading unit 5.

In block 4, each of the discrete signals, other than the "zero signal of a uniform background," transforms the control pulses of the luminance signals and coordinates by converting and amplifying. In block 5, a recording of the luminance signal is recorded in the corresponding cell of the memory device (for example, storage cathode ray tubes). Simultaneously from the output of block 4 to block 5, the control impulses are fed, which are fed to the deflecting beam recorder's deflecting beam system, the latter is ready to record a new luminance signal on the neighboring memory cell. In block 6 of the formation of the coordinate code signals, to which the control pulses arrive, and from block 4 II are synchronized pulses from the generator generator 2, are formed

 123197

quantized code group pulses determining the position of the recorded element on the line (relative to the beginning of the line).

The code signals are recorded in the corresponding memory locations of several storage devices 7 and 5 (for example, storage cathode ray tubes). The deflecting devices of these tubes are controlled by pulses from block 4. A horizontal sync pulse is fed through a separate channel to blocks 4, 5, 7, 8 and recorded in memory devices after giving it the appropriate shape, which it can be further highlighted among other recorded pulses. After the recording is finished, a read cycle follows, in which the signal recorded on all storage devices is read synchronously and in phase with linear sweeps during a television frame. The signals obtained when reading from the output of blocks 5, 7 and 8 are transmitted through a channel with a narrowed bandwidth to the input of the receiving device. At the receiving device, the signals are quantized and recorded in the corresponding ' devices.

After the end of the write cycle, synchronous and in-phase reading of the signals is made and they are overwritten by means of a potentialoscope, the modulator of which is given a luminance signal, and the corresponding position signals are sent to the deflecting device. In the image recorded on the target, the initial distribution of image elements on a uniform background will be restored. When transmitting low-detail black-and-white images without halftones, such as black images on a white background, recording and transmission of luminance signals is eliminated, and positional pulses are transmitted. The number of pulses in a code group is determined by the number of discrete positions of the elements that must be resolved and, from the noise immunity point of view, desirable by the dynamic range.

Subject invention

A method of narrowing the spectrum of a television signal by transmitting quantized differences in luminance and coordinates of image elements, the brightness of which differs from the brightness of surrounding elements, characterized in that, in order to improve noise immunity, the coordinates of the image elements are transmitted as cudo groups recorded by storage devices.