SU1223409A1 - Meter of differential distortons - Google Patents

Abstract

 The invention relates to a television technique. Measurement accuracy is improved while reducing measurement time. A color subcarrier is extracted from a television measurement signal affected by noise and distortion, using a bandpass filter 1, and a horizontal sync pulse that is fed to the first pulse shaper (PI) 9 via the sync selector 8 via the automatic gain control unit 2 , calibrator 3 differential amplification, amplitude detector 4, the second block is gated with 4 O co (Pi / r. i

Description

Neither (BS) 19 and amplifier 6 is fed to a synchronous filter (SF) 7. At one output of the SF 7, a differential gain signal is generated, and at the other output six constant voltages. From the output of the amplitude detector 4, the signal arrives at the second FI 10, where the pulses from the first FI 9 are also supplied. Both FI 9 and 0 and the driver 12 of the control pulses, which receive the pulses from the clock generator II, generate control signals for the differential meter units distortions. The elimination of parasitic amplitude modulation of the color subcarrier from the automatic gain control unit 2 and the differential gain signal from the SF 7 are sent to the amplitude modulator 13. From its output, the compensation I.

The invention relates to a technique of television and can be used to measure the differential phase and differential amplification of video recorders.

The purpose of the invention is to improve the measurement accuracy while reducing the measurement time.

FIG. a structural electrical circuit for measuring the potential distortion; in fig. 2 and 3 - signal plots.

The differential distortion meter includes a band-pass filter I, an automatic gain control unit 2, a differential gain calibrator 3, an amplitude detector 4, a first gating unit 5, usi;:: itel 6, a first synchronous filter 7, an sig- nal collector 8, the first and second drivers 9 and 10 pulses, clock generator 11, driver of control pulses 12, amplitude modulator 13, amplitude limiter 14, differential phase calibrator 15, phase detector 16, delay element 17, phase shifter 18, second gating unit 19 , the switching noise suppression unit 20 innarly in the amplitude of the color of the air is supplied to the amplitude limiter 14 to eliminate the bursts, and then through the calibrator 15 and through the delay element 17 and the phase shifter 18 to the phase detector 16. From its output, the signal detected by the phase subnet is gated in the first BS 5, passes through the switching noise suppression unit 20, integrates into the integrator 21 and arrives at the second SF 22. At one output of the second SF 22 a differential phase signal is generated, and at the other six constant voltages corresponding to the differential phase. The constant voltages at the outputs of the SFs 7 and 22 are used by the digital indication of the magnitude of the differential distortion. 3 il.

2

Tegrator 21 and the second synchronous filter 22.

The device works as follows.

A television measurement signal A (FIG. 2) arrives at the input of the differential distortion meter, which is affected by impulse noise, fluctuation noise, close to white, temporal, differential phase and differential amplitude distortions. From the signal A, the color subcarrier B is selected using a bandpass filter 1 having a central

a frequency equal to the frequency of the color subcarrier B, and a passband that is not passed around for undistorted transmission of all components of the differential gain signal (M) and the signal X

(fig.Z) differential phase (DF). Further, the color subcarrier B arrives at block 2, where it acquires a strictly normal span of the first zero burst, independent of the amplitude modulation of the color subcarrier. Block 2 is controlled by pulses B. The first driver of 9 pulses is triggered by horizontal sync pulses received from sync selector 8, which extracts them from signal A. Using calibrator 3, signal B is entered (in calibration mode) with additional amplification according to the pulses G, coming from the first shaper 9 pulses. The difference in gain is set to 10%. The amplitude-calibrated signal D is fed to an amplitude detector 4, at the output of which a signal E is generated, which is fed to the second driver 10 pulses. This also comes pulses W, formed by the first shaper 9 pulses. In block 19, the signal E is gated by pulses W and the level U is tied to the level u. At the output of amplifier 6, a signal .3 is extracted, in which and | UQ and u is below the UQ level by an amount (U - U) corresponding to 10% of the amplitude difference between adjacent lines. The pulses AND are produced by the clock generator 11, which is triggered by pulses from the output of the driver 10 and is fed to the driver 12 of the control: the pulse of pulses. As a result of processing the signal 3 by the first synchronous filter 7 with the help of control pulses K, L, arriving at its second input on. its second output generates a differential amplification signal M. At the first output of the synchronous filter 7, six constant voltages are allocated corresponding to the amplitudes of the A signal bursts. The described part of the circuit is intended to separate the differential amplification signal M from the input signal A and then use it elimination of the parasitic amplitude modulation of the signal B. In addition, this part of the scheme makes it possible to measure the magnitude of the distortion of the type and the differential gain, measured in percent according to calibration. To eliminate the parasitic amplitude modulation of the colorless, the existing B is fed to the amplitude modulator 13, the second input of which receives the differential amplification signal M. From the output of the amplitude modulator 13, the amplitude-compensated color subcarrier H is fed to the limiter 14 of amplitude to eliminate the saved bursts. Further, the phase modulated color subcarrier C arrives at

223409

Calibrator 5 and delay element 17.

The first input of the phase detector 16 receives a delayed signal P from the output of the phase shifter 18. In the calibrator 15, the phase 10 K is added (in the calibration mode) (f in the section corresponding to the duration of the calibration pulse P that arrives at the other input of the calibrator d 15 from the first generator 9 pulses. The accuracy of calibration in this way does not depend on the differential phase distortions present in signal A. Thus, the calibrated out of phase color subcarrier C arrives at the second input of phase detector 16, delayed and relative color subcarrier n on half the length of packets from the first to fifth phase shift Wed 90 exhibited emym phase shifter 18. The signal detected by the color subcarrier phase T is strobed in the first block 5 gating pulses F and pref binds level (cfo G) to the level of

five

20

. At the output of switching interference suppression unit 20, there are no interferences j,, y in the signal-y, which is then integrated into

integrator 21 over positive30 ","

NOOs of the length J, which is also fed to the integrator 21.

The integrated DF signal (Fig. 3) is processed by the second synchronous filter 22, to the other inputs of which 35 control pulses X and L are sent from the control driver 12 pulses triggered by pulses I. Signal differential 4) of the potential phase C at the second output of the second synchronous signal

 Filter 22 and the signal F at the output of the integrator 2 are shown in the calibration mode, since in the measurement mode they will have a different shape and span Uaip. The magnitude of the level U, corresponding to the reference voltage (| n 10 is set in volts by adjusting the transfer ratio of the integrator 21. On the first run of the second synchronous filter 22, there are six constant voltages corresponding to the differential phase of the signal A bursts. Hojp phase distortions are measured in degrees in accordance with the calibration carried out when adjusting the meter. The constant voltages at the first outputs of the first and second synchronous filters 7 and 22 can be used

for digital indication of the magnitude of the differential distortion.

Claims (1)

Invention Formula A differential distortion meter comprising a bandpass filter, a sync selector, an integrator and a serially connected delay element, a phase shifter, a phase detector and a first gating unit, the input of the bandpass filter combined with the input of the sync selector and is: In order to improve the measurement accuracy while simultaneously reducing the measurement time, an automatic gain control unit, a differential gain calibrator, and an amplitude detector are introduced. p, amplifier, first and second synchronous filters, first and second pulse shapers, clock generator, control pulse shaper, amplitude modulator, amplitude limiter, differential phase calibrator, second gating unit and switching noise suppression unit that is connected between the output of the first unit the gate and the integrator input, while the automatic gain control unit, the differential gain calibrator, the amplitude detector, the second strobe unit, the amplifier, the first Chron filter, an amplitude modulator of the amplitude limiter and the differential phase calibrator connected in series a band pass filter output and the second input of the phase detector, Yu-controlled,. The inputs of the automatic gain control unit, the differential gain calibrator, the differential phase calibrator, and the first input of the second coi pulse generator (3 dinene with the corresponding outputs of the first pulse former, whose input is connected to the output of the sync selector, the control inputs of the first and second gating blocks 3 blocks 5 switching: interference and integrator combined with the input of the clock generator and connected to the output of the second pulse generator e whose second input is connected to the output of the amplitude detector, output. the clock generator is connected to the input of the control pulse generator, the first output of which is connected to the control inputs of the first and second synchronous filters, the second output of the control pulse generator is connected to the second (secondary control input of the second synchronous filter, whose information input is connected to the output the integrator, the second input of the amplitude modulator is connected to the output of the automatic gain control unit, the output of the amplitude limiter is connected to the input 5, and the outputs of the first and second synchronous filters are outputs of a differential distortion meter. Ui f / 1 --VHiHi g lllll LLLLLLL- 1 Ug, .4, У5 / VV / "V & Shhhhh 0-i- Mr. Chin IMIMMlLllillii MS Ch.  .- {y shddinishshish t. vvk J  ". y / y J and uv Compiled by A. Prozorovsky Editor T. Kugrpeva Tehred I. Veres Proofreader V. Sinitska Order 1727/61 Circulation 62A Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab, d. A / 5 Filial mm Patent, g, Uzhgorod, st. Project, 4