SU1734238A1 - Method of determination of time divergence of brightness and chromaticity signals - Google Patents

Abstract

The invention relates to a television measurement technique and can be used to measure the time difference between luminance and chroma signals. The purpose of the invention is to improve accuracy. The method consists in that they generate low-frequency - A (t) and radio-pulse - B (:) sin al: components of the measuring signal, where B (m) is the envelope of the p-pulse signal; t - time, si - angular frequency, form the measuring signal in the form U0 (t) A (t) + B (t) sin cot, additionally form the measuring signals in the form Uk (t) A (t) - B (t) sin W t + kTT / 2, k 1.3, pass the signals Uk (t) k 0.3 through the television path, the instantaneous values of each of the four measurement signals are measured at the output of the path, the instantaneous values of the radio pulse envelope are determined at each moment time g according to the formula "0), HgO) () -w (Oi2 and the instantaneous values of the low-frequency signal at each moment of time t - according to the formula: A (t) 1 / (t) - Ui (t) + U (t) + Uaw ayut signal B (t) no relation to the signal A (t) at time T Browse // A (t) -. B (t-T) min, where the time offset value T corresponds to the sought parameter SP C 8 yl.

Description

The invention relates to a television measurement technique and can be used to measure the difference in time between luminance and complement signals.

The purpose of the invention is to improve accuracy.

FIG. Figure 1 shows a generalized structural electrical circuit of the device that implements a method for determining the difference in time between the signals and the brightness and chromaticity of the television path; in fig. 2 - structural electrical sem of the output block of synchronization and conjugation with

TV path; in fig. 3 is a structural electrical circuit of the input unit for synchronization and interfacing with a TV; in fig. 4-7 - time diagrams of signals, respectively; in fig. 8 is a timing diagram of the reconstructed low-frequency envelopes and the radio impedance component of the measurement signal. These models simulate the luminance and chromaticity signals, respectively, as part of the full color video signal.

A device that implements the proposed method, contains the IT unit 1 calculating the component of the television measuring

h

: with you

00

signals, the first multiplexer 2. the first to fourth memory blocks 3-6, the output block 7 of synchronization and interface, the television path 8, the input block 9 of synchronization and coupling, the generator 10 zones, the second multiplexer 11, the fifth - eighth blocks 12 - 15 memories, computing unit 16, control block 17.

The output block of synchronization and conjugation (FIG. 2) contains an address counter 18, a pulse shaper 19, a digital-to-analog converter 20, a clock generator 21, a first spectrum conversion unit 22.

The synchronization and coupling input unit (FIG. 3) contains a second spectrum conversion unit 23, an analog-to-digital converter 24.

The method for determining the difference in luminance and chroma signals is that they generate low-frequency (A (t) and radio-pulse (B (t) s); n al components of the measurement signal, where B (t) is the envelope of the radio-pulse component; t is time; W- angular frequency, form the measuring signal in the form

U0 (t) A (t) - B (t) sin wt

additionally form the measuring signals in the form

Uk (t) A (t) + B (t) sm al + K „t / 2. k - 1 3 (1)

signals Uk (t), k 0.3 are passed through the television path, the instantaneous values of each of the four measuring signals are measured at the output of the path, the instantaneous values of the envelope of the radio pulse component are determined at each time instant t by the formula

in (t)

 1/2 U0 ((t) (t) -U3 (i) 2

(2)

and the instantaneous values of the low-frequency signal at each time instant t are given by the formula

A (t) 1 (t) + Ui (t) + U2 (t) + U3 (t) (3)

then shift the signal B (t) with respect to the signal A (t) at time T according to the criterion:

|| A (t) -B (t) -T) (4)

wherein the value of T is the desired parameter.

The device implementation method works as follows.

Block. 1, the components of the TV measuring signals (Fig. 1) calculate the values of the samples of the four phases of the measuring signal (Fig. 4-7) with a sampling interval satisfying the conditions of the Kotelnikov theorem and write them into blocks 3-6 of memory. Address code, as well as other signals,

0 required for control of the memory blocks are generated synchronously with the calculated signal samples by the calculation unit 1 of the component IT of the measurement signals and, through the first multiplexer 2, they determine the cell number and the memory block number where the value of the corresponding sample is written, and control the operation of the blocks Memory 3-6 Sampling values of other components in a single number / signal

0 synchronization are calculated by block 1 for calculating the components of the TV measuring signals and recording the B blocks of memory in the same way. The state of the first multiplexer 2 is set from the output of block 1 for the calculating 5 components of the TV measuring signals. After recording the signals in memory blocks 3-6, the first multiplexer 2 switches to a hook, that the code of the current address starts to arrive at the inputs of memory blocks 3-6.

0 TV metering signal and other signals necessary for control of memory blocks from the output block 7 of synchronization and interface with the TV path In re / lotta at the input of this block alternately signals that form together with the synchronization signals and other components The TV measurement signals read from the same memory blocks 3-6, the digital equivalent of the TV measurement signal that comes from the output of block 7 is fed to the TV-tract input in the form suitable for transmission, the output signal from the TV path output at the entrance Noah block 9 synchronization and interface with the TV path, with

5 outputs of which the received signals are alternately recorded in memory blocks 12-15. The code for the current address of these signals and other signals necessary for controlling the memory blocks are generated in the generator.

0 zones 10 and are fed to memory blocks 12-15 through the second multiplexer 11, which is set to this state by a signal from the output of control block 17. This signal is generated as follows.

5 Parallel binary code current

the addresses of the TV measurement signal from the generator output of zones 10 are fed to control block 17, where codes are output from the output of computing block 16 that determine the numbers of the first and last samples of the region

TV measurement signal, on which the measured component is located. When the code of the current address coincides with the codes of the selected first and last samples, two pulses are successively formed, which are used to form a square pulse corresponding to the boundaries of the analyzed portion of the TV measuring signal in the frame. At the end of this pulse, the second multiplexer 11 enters a state where the address code and other signals necessary for controlling the memory blocks are output from the computing unit 16 through the block 11 to the inputs of the memory blocks 12-15, while the computing unit 16 receives a sample of the measuring signal at the address given to it.

When calculating by expressions (2) and (3) for every four samples from blocks 12-15, corresponding to each value of the address, i.e. time t, the values of the low frequency component and the amplitude envelope of the radio-frequency component of the TV measuring signal (Fig. 8) are obtained, which are recorded in the operational memory of the computing unit 16. The magnitude of the distortion — the time difference between the luminance and chromaticity signals — is determined in FIG. 8 and criterion (4), if necessary, both averaging of data recorded in memory blocks 12-15 and digital processing of the results of calculating the low-frequency and radio pulse amplitudes of a TV measuring signal (filtration, analysis of signal sections, etc.) can be used. ) and averaging the results of calculating the parameter of the difference in luminance and chrominance signals.

Depending on the type of TV path, the structure of the input and output blocks 7 and 9 of the synchronization and conjugations vary as follows.

In the case when the TV path is analog, low-frequency (0 ... 6 MHz), the input synchronization and conjugation block (Fig. 2) contains a clock generator 21 generating two sequences of clock pulses PT and T2 whose repetition frequencies satisfy the condition of the Kotel'nikov theorem and correspond to the sampling frequency of the TV measuring signals. The pulses Tm are counted by the address counter 18, which produces the address code, the pulse generator 19 converts the address code to the signals necessary to control the DAC 20, which receives both clock sequences from block 21. The DAC 20 converts the sequence of samples in the form of codes to analog samples The TV signal, spectrum conversion unit 22, performs the function of a low-pass filter, which transmits frequencies up to 6 MHz and, if necessary, power amplification. An analogue TV signal is generated at its output. The input unit 9 of synchronization and interface with the TV path (FIG. 3) thus contains a block

0 23 spectrum conversions that filter low frequencies in the 0-6 MHz band, the output of which goes to the parallel A / D converter 24, the zone 10 generator extracts horizontal and vertical sync pulses from the TV signal and, using the phase-locked loop system, produces a parallel binary signal. the code of the current zone corresponding to the sample number in the row, the line number in the frame, and the phase number of the radio pulse component of the measurement signal. Here, also, two sequences of clock pulses are produced, the frequencies of which are equal to the sampling frequency of the TV measuring signal, and the phases coincide, respectively, with the beginning and middle time of each sampling code. These clocks control the operation of the ADC 24, which provides analog conversion

0 signal to the digital code, which is the output signal of the block 9 synchronization and conjugation.

In the case where the TV path is analog, the radio frequency first block

5 22 spectrum conversions provide the necessary spectrum conversions (modulation, filtering, etc.) in accordance with the selected TV system 6, as well as power amplification. The second spectrum converting unit 23 performs the inverse transformations.

In the case of a digital TV path, the input and output blocks 7 and 9 perform the following functions:

5, synchronizing the reading from blocks 36 and writing data blocks to blocks 12-15;

digital coding at the transmitting side and decoding at the receiving side (7); power and signal level coupling.

In the case of a hybrid (analog-digital TV path), depending on whether the input, the output of the TV path, or both, are digital, versions are used

5 input and output blocks 7 and 9.

Implementation of the main units and their nodes. The functions of calculating component 1 of the TV measurement signals can be performed by a computer, such as a personal computer. Shaper 19 pulses

can be made on the basis of standard digital integrated circuits that provide the necessary decoding and pulse generation using triggers. Unit 16 provides an indication of the measurement results.

The proposed method, by forming a new type of TV measuring signals and calculating by formulas (2), (3) and (4), provides the definition of the law of the envelope amplitude for each sample of the TV measuring signal without the use of detection and limiting the spectrum. the errors introduced by these transformations, as well as the additional error caused by the instability in time or when measuring the ambient temperature, the delay time introduced during these transformations. In addition, when determining the discrepancy in time of the luminance and chroma signals, the whole A (t) and B (t) signals are used, not their individual values at characteristic points, which improves the signal ratio (noise in the measured value).

The invention improves the accuracy of measuring the difference in luminance and chrominance signals.

Claims (1)

Invention Formula The method of determining the difference in time between the luminance and chroma signals in the television path, in accordance with which the low-frequency (A) (t) and radio-pulse (B (t) sin with t) components of the measurement signal are generated, where B (t) is the radio-frequency pulse component voy; t - time; a) - angular frequency, form the measuring signal in the form Uo (t) A (t) + B (t) sinon pass it through the controlled television path, shift the signal B (t) relative to the signal A (t) by time T according to the criterion || A (t) -B (t) -T / lh min moreover, the value of T is the desired parameter, characterized in that, in order to increase the measurement accuracy, the measurement signals are additionally formed as Uk (t) A (t) + B (t) sin a) t + k / 2, k 1,3 they are passed through the television path, the instantaneous values of each of the four measurement signals are measured at the output of the path, the instantaneous values of the envelope of the radio pulse component are determined at each time instant t using the formula in (t)  1/2 U0 ((t) ((t) 2 and the instantaneous values of the low-frequency signal at each time instant t are given by the formula A (t) 1 (t) + U i (t) + U2 (t) + U3 (t). Have F ABOUT -five 10 -I Cro tf 23 Fie.2 - g Fig.Z  good ns | -tX 91  | UrN , yr SL -t - t-