SU946010A1 - Device for measuring parameters of colour television channels - Google Patents

Description

(54) DEVICE FOR MEASURING TRACT PARAMETERS

COLOR TELEVISION

one

I The invention relates to television, and can measure the characteristics of individual sections of radio-relay, cable peaks, on transmitting television stations and earth stations of satellite peaks associated with the transmission of a full-color video television signal.

A device is known for measuring the parameters of the color television paths, containing a bpok of separating sip and chrominance signals, the first output of which is connected to the first, second and third inputs of a switch of the type, 5 scientific research institutes through serially connected attenuator and bpok of analog processing, luminance signals and the second output of the luminance and chrominance separation unit is connected to the fourth input of the switch of the measurement type via the delay line, to the fifth input of the switch of the measurement type directly o, and the first and second outputs of the measurement switch ida are connected to the adder, and the indicator Cl.

However, the known device does not provide sufficient measurement accuracy.

The circuit of the invention is an increase in measurement accuracy.

The goal is achieved in that a device for measuring parameters of color television paths, comprising a luminance and chrominance separation unit, the first output of which is connected to the first, second and third inputs of the measurement type switch via serially connected attenuator and analog processing unit chrominance, and the second output of the luminance and chrominance separation unit is connected to the fourth switch of the type of measurement through a delay line, and to n m (at the input of the switch and the measurements are directly, and the first and second outputs to (1 switch of the type of measurements are connected to the adder, and the indicator, the driver of the pulse generator, the coincidence unit, the OR element, the driver of control pulses and the noise suppression block, are entered, while the driver of the pulse generator is connected to the nepBONTy input of the control pulse generator through the series-connected coincidence block, the OR element, and the second output of the analog signal processing unit and the central signal amplifier is connected to the second input of the control pulse generator etnosti, and the first, second and third output of the control pulses are respectively connected to the first input interference cancellation unit and to second inputs of the block matcher and rsi element and the adder output is connected to the second input of the fur suppressing unit 5 whose output is connected to the indicator. FIG. 1 shows a structural electrical circuit of the proposed device; in fig. 2 - voltage diagrams for his work. The device comprises a block of luminance and chrominance signals, a delay line 2, an attenuator 3, a block 4 of analog processing of luminance and chrominance signals, a switch 5, an adder 6, a pulse shaper 7, a coincidence block 8, an OR element 9, a shaper control pulses 11 noise suppression indicator 12. Block 4 of analog processing of luminance and chroma signals consists of an amplitude detector (BP) 13, a phase detector (PD) 14, a reference frequency generator 15, a delay line 16, and a limiter amplifier 17. The device works as follows way. The test signal distorted in the television path (Fig. 2a), containing a complex synus-quadratic pulse, is fed to the input of block 1, in which the separation is performed using filters on the high-frequency (Fig. 26) component (chrominance signal) and low-frequency (Fig. 2c) component; (luminance signal) In the case of measuring the difference in luminance and chroma signals (PB) in time, the chrominance signal from the output of block 1 is fed to the input of attenuator 3, which in this case has zero attenuation. From the output of the attenuator 3, the signal is fed to the input of the amplitude detector 13 of block 4, at the output of which a color envelope is selected. Dale, the selected signal is fed to the input of the US0 limiting block 17 of block 4 from the output of the limiting amplifier 17, the signal limited to half its full span, through the switch 5 is fed to one of the inputs of the adder 6, and to the other its input from the other output of the unit 1 through the delay line 2 and the switch 5. As a result, the output of the adder 6 generates a voltage representing a signal with two maxima (Fig.). By varying the delay time of the luminance signal (Fig. 2c) using the delay line 2, the equal amplitudes of the signals (Fig. 2d, d), which can be observed, are achieved; On the display 12. The delay switch 2 readings represent the divergence of the luminance signals and chromaticity in not. In the case of measuring the difference in amplification of the luminance and chrominance (RF) signals, the chrominance signal through the attenuator 3 and the amplitude detector 13 of block 4 is fed to the delay line 16, which provides a delay of more than or equal to the duration of the test signal, measured at its base. The chrominance signal envelope thus delayed is fed to the input of the switch 5 from the output of which the signal goes to one of the inputs of the adder 6, and to the other input it is given a luminance signal from the other output of block 1 through the pin 2 delay, having in this case a delay equal to O, and switch 5. At the output of the adder 6, a signal is generated (Fig. 2e, g) consisting of luminance signals and a chrominance signal envelope sequentially arranged in time. The attenuation change introduced by attenuator 3 ensures that the amplitudes of these signals are equal, which can be seen on indicator 12. In this case, the indications of attenuator switch 3 represent the difference in amplification of luminance and chrominance signals in dB. In the mode of measuring the differential phase (DF) and differential amplification (DU), a test signal is supplied to the input of unit 1 containing a sawtooth signal with a high-frequency tip (Fig. 2h). In the case of measuring the DU, a sinusoidal voltage of 4.43 MHz allocated to the first output in block 1, through attenuator 3 is fed to the input of the amplitude detector 13 of block 4, the output of which includes the envelope sinusoidal voltage (Fig. 2i). From the output of the amplitude detector signal 13

; delay time 16, which in this case has Ja epjy equal to zero, switch 5, adder 6, is fed to the input of indicator 12, i.e. to determine the remote control, i.e. A / B1OO ratios, using an attenuator, set the 3 span of a V to 1 V. At the same time, the value of the control in percentage is A 100%.

In the case of measuring the DF, the separated signal from the output of block 1 through attenuator 3, which in this case has zero attenuation, is fed to one of the inputs of the phase detector 14 of block 4, with which the test signal is compared with the reference frequency signal supplied from the output of generator 15 the reference frequency to the other input of the phase detector 14. A signal is generated at the output of the phase detector 14 (FIG. 2k) proportional to the phase difference of the signals (the gaming frequency t of the test signal. The received signal from the output of the phase detector Ora 14 through the switch 5 and the adder 6 is fed to the indicator 12. To determine the DF is necessary on the waveform (Fig. 2k)

measure its maximum f uiah minimum value,

In the measurement mode of cross-distortion chromaticity-brightness (D-J) to the input of block 1 A three-level test signal is supplied (FIG, 2L). The selected low-frequency component of this signal has the form (FIG. 2m) in the presence of distortion, from the output of the block 1 through the switch 5 and the adder 6 is fed to the input of the indicator 12. To determine the magnitude of the distortion, the ratio .A1L-1BO% is measured,

In the presence of fluctuating noise in the measured channel, it is possible to connect the interference suppression unit 11, controlled by the control pulse shaper 10, which is triggered when a selected signal appears at the output of the amplitude Detector 13 unit 4.

In order to expand the applicability of the proposed device both on the communication lines and on television centers, it is necessary that this device work both with and without a personnel extinguishing pulse. For this purpose, the device provides for kick extraction of a frame extinguishing pulse from the synchro mix and its formation in the absence of a synchro mix. In the presence of a frame extinguishing pulse, an internal frame former of a damping impulse, containing the 13 Hz pulse shaping unit 50, the OR element 9 and a match block 18, which operates as follows.

If there is a frame damping pulse in the synchro mix in the former 10, a frame damping pulse occurs at the output, and a voltage blocking block 8 is located at the other end of the block.

this impulse through the element OR 9 is fed to the input of the imaging unit 10, in which impulses are formed, ensuring the normal operation of block 11,

In the absence of personnel extinguishing

impulse in synchro mix from the output of the forlli, the rotator 10 to the block 8 receives a voltage that opens it. In this case, the rectangular pulses formed by the output of the driver 7, to the input of which a sinusoidal voltage of 50 Hz is applied (for example, from an alternating current network), are fed to the output of the block 8, and then through the element OR 9 - also to the input of the generator Yu .

The use of new elements and connections significantly distinguishes the proposed meter from the new known ability to measure additionally DF, DU, C-I, i.e., the parameters necessary for evaluating the quality indicators of the paths intended for transmission of color television. The device allows panoramic observation of measured characteristics, for example, on an oscilloscope, which will allow the most

precisely adjust the path for color television transmission.

Claims (1)

Invention Formula 40 A device for measuring color television path parameters containing a chrominance luminance signal separation unit, the first output of which is connected to the first (lu, second and third inputs of the measurement type switch via serially connected attenuator and analog signal processing unit of chrominance and chrominance, and the second output of the block the separation of luminance and chroma signals is connected to the fourth input of the switch of the measurement type via the delay pin and to the fifth input to the 1 switch of the measurement type directly, and the first to the second switch output of the measurement type is connected to the adder, and the indicator that, with the accuracy measurement circuit {Ni, a pulse former was introduced. The match block, the OR element, the control pulse generator and the noise pressure block; the output of the pulse generator is connected to the first input of the control pulse generator via the serially connected match block, the OR element, and the fourth output of the control pulse generator is connected to the fourth output the analog processing unit of the luminance and chrominance signals, and the first, second and third outputs of the control pulse driver are connected respectively to the first input of the interference suppression unit and to the second m inputs of the coincidence unit and the element AND LI, and the output of the adder is connected to the second input of the interference suppression unit, the output of which is connected to the indicator. Sources of information taken into account in the examination 1. USSR Author's Certificate (N9 399О8О, class H 04 B 7/02, 1971 (prototype).  -AA where SP l FIG. 2 m