SU573908A1 - Device for measuring subcarrier frequency in colour signal of"secam" system - Google Patents

Description

connected to the BTopo jy input gated unit.

FIG. 1 shows the structural, electrical scheme of the proposed meter; FIG. 2 gives time diagrams for his work.

Measure the subcarrier frequency in the chroma signal of the SEC AM system with the filter Ij connected by the input through a series-connected selector of 2 cimx pulses, the control unit 3 and the unit averaged 4 to the first input of the counting decade unit and the display 5, the second input of which is connected to the output of the selector 6 of pulses connected by the first input to the second output of the control unit 3, the second and third inputs of which are connected respectively to the output of the reference frequency generator 7 and to the second output of the averaging block 4. In addition, the meter contains u sequentially connected gating unit 8, connected to output fmpa 1, element OR 9, first delay 1O pinchr, compensation unit 11, connected to the second input of the selector 6 pulse id, second PSh1ShO delay 12, the output of which is {{shyuchen to the third input selector 6 imiynbCOB, the amplifier-limiter 13 and the element And 14, Output. The second delay line 3.2, through series-connected amplification, limits 13 and element 14, connected to the third output of control unit 3, is connected to the second input of element 9, and the fourth output of control unit 3 is connected to the second input of gating unit 8.

The meter works as follows.

The signal, encoded by the SECAM system (Fig. 2a), is fed simultaneously to the filter 1 and the selector 2 clock pulses. Using filter 1, a chroma signal is extracted and its amplitude modulation is eliminated. C; the output of the filter 1 ctirHan is fed to the first input of the gating unit 8 and passes to its output during the operating time of the control pulse 8 from the control side 3 (Fig; 2b). Thus, one (yboy) line of the television raster is selected for the measurement circuits., °

. The 8 gb skipped by the gating unit, the cash is fed by an element. OR 9 to the input of the first delay line 1O at the line time. From the output of the first delay line, the attenuated signal (Fig. 2c) is fed through the compensation unit 11 to the input of the second delay line 12 and to the first input of the selector 6. From the output of the delay line 12, the signal p. Zt-to the second input of the selector 6 ( Fig. 2d) and through the stop device 13 to the controllable input of the And 14 element. To the other input of the And 14 the pulse is generated, feedback loops (Fig. 2e) from the control unit 3. The signal from the output of the And 14 goes through the element OR 9 to the input of the delay line 1O, Thus, the signal of the selected line is stored It is not available for the duration of the control pulse (Fig. 2e) from the control unit 3,

those. for the time of one complete measurement cycle. It is obvious that no fluctuations in the frequency of the measured signal, the effect of which causes the appearance of additional errors in the statistical processing of the results of many individual measurements, in this case do not affect the final result of the measurements.

The signals at the inputs of the selector 6 are shifted relative to each other by the time of the row (Fig. 2c and 2d) and appear at the corresponding input through the row. In general, testing of the measured signal in the selector 6 with the help of strobe pulses (Fig. 2e) is performed every line during the whole measurement cycle.

The strobe pulses are generated in the control unit 3 from the high-frequency-frequency signal of the reference frequency generator 7.

The duration of the strobe pulse, which determines the time of a single measurement, and its location in the interval of the active part of the line are determined by the control unit 3, which allows the carrier frequency to be measured in a wide

class of test signals and images. The restructuring of the selection of the signal area for measurements can be carried out either manually or automatically by a predetermined program.

From the output of the selector 6 packets counting

The pulses (Fig. 2g) are fed to the input of the block of counting decades and of the display 5, where they are counted during the full measurement cycle time, which is determined by the

the equalizing signal coming from the control unit 3 through the averaging block 4 to the block of counting decades to the display 5. Po. At the end of the measuring time Tzsm (fig, 2d), a command is sent along the reverse FLAG circuit.

from the block; and averaging 4 to the control block 3, which breaks the feedback loop on the control input of the element 14, stops the flow of strobe pulses to the selector 6 and, consequently, the process

accounts in the block of counting decades and indications 5. The result obtained is displayed on the digital display for the duration of the indication or displayed on the digital printing. Then, the previous result is reset.

Claims (1)

and the device is being prepared for a new measurement cycle. With the appearance of the next control pulse (Fig. 26 /, the process of camera k is repeated). With the help of the selector 2 clock pulses, all processes of control of the operation of the device are synchronized. The described meter has an increased speed and accuracy of measurement Improving the accuracy of measurements contributes to improving the quality of television hanging in general. Claims of the invention A subcarrier frequency meter in the chroma signal of the SECAM system; containing a filter connected by an input through a series-connected clock selector, a control unit and a Neney block to the first input of the counting-decade block and display, the second input of which is connected to the output of an impulse selector connected to the second input of the second control unit, the second and third inputs of which are connected correspondingly to the output of the reference frequency generator to the second output of the averaging unit, characterized in that, in order to increase the measurement accuracy and the meter performance, in neg o successively inserted enabled gating unit connected to the filter output, OR element, first delay line, compensation unit connected to the second input of the pulse selector, second delay line, the output of which is connected to the third input of the pulse selector, limiting amplifier and element And the output of the second delay line through the series-connected limiting amplifier and the AND element connected by the second input to the TpeTbekfy output of the control unit is connected to the second input of the OR element, and the fourth to The output of the control unit is connected to the second input of the gating unit. Sources of information taken into account in the examination; 1. USSR author's certificate No. 447858, cl. H O4 IV 7 / O2, l971. figure 1