SU803127A1 - Method of measuring discrepancy in time of brightness and colour signals in television channels - Google Patents

Description

(54) METHOD OF MEASUREMENT OF EXPANSION IN TIME

SIGNALS OF BRIGHTNESS AND COLOR

ON TV TRACKS

relative to a sinus quadratic radio pulse by one step of quantizing the interval of maximum time difference in the measured television path, while at the instants of coincidence in time on the transmitting side of the television path of the sinus quadratic radio pulse and the sinus quadratic video pulse a television pulse is mixed in the television signal, which determines the instant of the beginning of measurement the time difference between the luminance and chroma signals at the receiving side of the television path, and the end of reference is REPRESENTATIONS Time luminance and chrominance signals determined on the moment in time coincidence constituent luminance and chrominance.

FIG. 1 shows the transmitting (FIG. 1 a) and receiving (FIG. 1 b) sides of the device implementing this method; in fig. 2 shows voltage diagrams at various points in the device circuit.

The device contains on the transmitting side a test signal generating unit 20 T with an envelope, adder-reader 2, a unit of forming a video impulse that is periodically shifted in time, a coincidence element 4, an insertion device 5. On the receiving side of the device are a test signal extraction unit 6, a luminance and chrominance component separation unit 7, a comparison element 8, a marker pulse extraction unit E, a quantization pulse generator 10 and a measurement unit 11.

The device operates as follows. On the transmitting side, synchronization pulses (Fig. 2.6) from the synchronizer are fed to block 1 to form a test signal of 20 T from the envelope.

From the output of block 1, the synchronization clock cycles (Fig. 2, e), with a frequency equal to the frequency of the test signal following (the synchronization pulses follow the same frequency), go to block 3, where an additional video pulse periodically shifted in time is formed the same envelope shape gin2.x (c) (Fig. 2, h), as the test signal. This additional video pulse is periodically shifted in time in each transmission cycle or less often relative to the test signal by one quantization interval of the maximum possible distortion in the measured path, C of the test signal generating unit 1 of the test signal is applied to the adder-subtractor 2, to which the envelope (Fig. 2, e) from block 1 and envelope f d) from block 3 (Fig. 2, h) is also shifted in time; in adder-subtractor 2, where the test signal 20 T arrives compensate for his sinuskvadra ary moiety, then the resultant signal is added to the additional video pulse is shifted in time.

The resulting total test signal from the output of the adder-subtractor 2 (Fig. 2, and) is fed to an input device 5, to which another input receives a television signal. In addition, a marker pulse from the output of the coincidence element 4 (Fig. 2, k) is fed to the insertion device 5 for mixing into the television signal at the time of coincidence (on the transmission side) of the pulses generated in blocks 1 and 3. For the formation of marker pulses From the synchronizer to the coincidence element 4, the input cycles are applied (Fig. 2, a), following the same frequency as the test signal. In addition, from the output of block 1 to element 4, the strobe pulses of the test signal are shown (Fig. 2, c), and from the output of block 3, the strobe pulses of the displaced video impulse are formed (Fig. 2, g): the coincidence of these pulses at the output of the coincidence element 4 forms a marker pulse. Thus, at the output of the insertion device 5, a television signal is formed with a test signal of 20 T, the envelope of which is shifted in time, and a marker pulse replaced into a video signal only during those transmission cycles of a test signal of 20 T., in which its syngas pulse coincides in time with its radio pulse color subcarrier.

At the receiving side, the video signal from the output of the measured path is fed to the input of the meter (Fig. 2, l). From the input of the meter, the signal arrives at the test signal extraction unit 6, where a pulse of 20 T is extracted for its further processing. From the output of block 6 (Fig. 2m), it is fed to a separation block 7, where its capacitance component is shifted in time (Fig. 2, n) and the envelope of the chroma signal (Fig. 2, o). The luminance component and chrominance signal envelope by; are given on the comparison element 8, in which the moment of their coincidence in time is determined, to which corresponds the pulse at the output of block 8 (Fig. 2n).

In addition, the video signal from the device input also goes to the marker impulse extraction unit 9, where the selection of the marker impulse, which is mixed in the full television signal on the transmitting side, occurs. The marker pulse from the output of block 9 (Fig. 2p) is fed to the block 11 of measurement. To determine the magnitude of the difference in luminance and chrominance signals, a generator of 10 quantization pulses is used, from the output of which quantization pulses (Fig. 2, s) are fed to measuring unit 11, counting pulses, the number of which (in terms of nanoseconds) corresponds to the distortion value of PB .

Claims (1)

In this case, the origin is determined by the moment of the absence of mutual temporal divergence of the luminance and chrominance signals on the transmitting side defined by the marker pulse, and the end of the counting by the moment of the absence of mutual temporal discrepancies of the luminance and chroma signals on the receiving side, determined by the pulse coming from comparing element 8 . The accuracy of measuring the magnitude of the RV of the luminance and chromaticity signals mainly depends on the magnitude of the quantization step (on the transmitting side), which with modern digital technology can be reduced to very small values. In addition, the measurement of the magnitude of the distortion at the receiver side is greatly simplified. Claims The method of measuring the difference in luminance and chrominance signals in television paths, based on the formation of a test signal on the transmitting side of the television path; consisting of the sum of the sinusquadratic video pulse, the luminance signal and the sinuskvadratic radio pulse of the color subcarrier, the replacement of the test signal with the television signal, and on the receiving side of the television path from the TV Upon receiving a 1nSg guard signal, a test signal is separated, which is divided into brightness and color, the envelope of the chroma signal is measured, and the time and time difference between the luminance and chromaticity signals, characterized in that, in order to improve the measurement accuracy, the transmitting signal is measured. On the side of the television path, the sinusquadratic video impulse is periodically shifted in time in each transmission cycle, for example, from line to line relative to the sinuskadratic radio impulse by one step of quantizing the MAC interval the maximum difference in time in the measured television path, while at the moments of coincidence in time on the transmitting side of the television path of the sinuskadratichesky radio pulse and the sinuskvadratichesky video pulse in the television signal knead the marker pulse, which determines the time of the beginning of the reference of the measured difference of signals of luminance and chromaticity on the receiving side of the television path, and the end point of the difference in luminance and chrominance signals is determined by the moment of coincidence in time components of luminance and chromaticity. Sources of information taken into account in the examination 1. Creepy M. I. Basics of television measurements. M., “Holy, 1976, p. 317-329 side On the transmission side P BUT rm BUT BUT