RU2076324C1 - Oscillograph - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: oscillograph is related to radio measurement technology. It incorporates deviation unit 1, two commutators 2,3, cathode-ray tube 4, sweep unit 5, synchronization unit 6, two stroboscopic converters 9,10 and delay line 11 which output is connected to first inputs of first 9 and second 10 stroboscopic converters. Inputs of sweep unit 5 and delay line are connected to output of synchronization unit 6 which output is connected to synchronization bus. First output of sweep unit 5 is connected to first input of second commutator 3 and to second input of second stroboscopic converter 10. Second output of sweep unit 5 is connected to second inputs of first 2 and second 3 commutators. Output of second stroboscopic converter 10 is connected to third input of second commutator 3. First and second inputs of cathode-ray tube 4 are connected correspondingly to outputs of second 3 and first commutator 2. First input of first commutator 2 and second input of first stroboscopic converter 9 are connected to output of deviation unit 1 which first input is linked to bus of measured signal. Output of first stroboscopic converter 9 is connected to third input of first commutator 2. Oscillograph also has voltmeter 12 and integrator 13 which input is connected to output of first stroboscopic converter 9. Output of integrator is connected to input of voltmeter and second input of deviation unit 1. EFFECT: increased measurement accuracy. 1 dwg

Description

 The invention relates to radio measurement technology and can be used in oscillography.

 Known oscilloscope [1] However, this device is characterized by low measurement accuracy and high measurement complexity, due to the error and the complexity of the visual reference, nonlinearity of the vertical deviation.

 The closest technical solution to the invention is an oscilloscope [2] containing a deviation unit, two switches, a cathode ray tube, a scan unit, a synchronization unit, a voltmeter, two stroboscopic converters and a delay line, the output of which is connected to the first inputs of the first and second stroboscopic converters, the inputs of the scanner and the delay line are connected to the output of the synchronization unit, the input of which is connected to the synchronization bus, the first output of the scanner is connected to the first input of the second comm utoator and the second input of the second stroboscopic converter, and the second output of the scanner is connected to the second inputs of the first and second switches, the output of the second stroboscopic converter is connected to the third input of the second switch, the first and second inputs of the cathode ray tube are connected to the outputs of the second and first switches, the first input of the first switch and the second input of the first stroboscopic converter are connected to the output of the deviation unit, the first input of which is connected to the bus the measured signal, and the output of the first stroboscopic converter is connected to the third input of the first switch and to the input of the voltmeter. When measuring on the waveform line, a luminance mark is formed. The voltage of the measured signal at the point indicated by the brightness mark on the waveform is equal to the voltage measured by the voltmeter divided by the gain of the deviation unit. The prototype error is due to the calibration error of the gain of the deviation unit and the non-linearity of its transfer characteristic.

 The prototype does not provide the possibility of measuring the amplitude of the pulse, the magnitude of which exceeds the product of the deviation coefficient by the size H of the working part of the screen vertically, since the movement of the waveform vertically by the adjustment bodies of the deviation unit causes a change in the voltmeter; this limits the accuracy of masking measurements by the waveform line of the structure of the measured pulse if the waveform of this structure is commensurate with the wavelength of the waveform.

 The purpose of the invention is the improvement of measurement accuracy.

 The goal is achieved by the fact that in an oscilloscope containing a deviation unit, two switches, a cathode ray tube, a scan unit, a synchronization unit, two stroboscopic converters and a delay line, the output of which is connected to the first inputs of the first and second stroboscopic converters, the inputs of the scanner and line delays are connected to the output of the synchronization unit, the input of which is connected to the synchronization bus, the first output of the scanner is connected to the first input of the second switch and the second input of the second stroboscopic of the second converter, and the second output of the scanner is connected to the second inputs of the first and second switches, the output of the second stroboscopic converter is connected to the third input of the second switch, the first and second inputs of the cathode ray tube are connected to the outputs of the second and first switches, respectively, the first input of the first switch and the second input of the first stroboscopic converter is connected to the output of the deviation unit, the first input of which is connected to the bus of the measured signal, and the output of the first stroboscope Cesky converter connected to the third input of the first switch administered voltmeter and an integrator whose input is connected to the output of the first stroboscopic converter, and an output connected to the input of the integrator and a second input of the voltmeter deflection unit.

 The drawing shows a block diagram of an oscilloscope, where 1 block deviation; 2 and 3, respectively, the first and second switches; 4 cathode ray tube; 5 scanner; 6 block synchronization; 7 sync bus; 8 bus of the measured signal; 9 and 10, respectively, the first and second stroboscopic converters; 11 delay line; 12 voltmeter; 13 - integrator.

 The oscilloscope operates as follows.

где Ar сигнал на входе интегратора 13; S знак интеграла; T период следования измеряемых импульсов, поступающих с шины 8 измеряемого сигнала; t - время. Сигнал с выхода интегратора 13 поступает на вход вольтметра 12 и второй вход блока 1 отклонения. При поступлении импульса синхронизации на вход блока 5 синхронизации с его второго выхода на вторые входы первого 2 и второго 3 коммутаторов поступает импульс, который на время развертки подключает выходы первого 2 и второго 3 коммутаторов к их первым входам. Импульс развертки с первого выхода блока 5 развертки через второй 3 коммутатор поступает на первый вход электронно-лучевой 4 трубки. Измеряемые импульсы, поступившие с шины 8 измеряемого сигнала, усиливаются блоком 1 отклонения и через первый 2 коммутатор поступают на второй вход электронно-лучевой 2 трубки. В результате на экране электронно-лучевой 2 трубки формируется осциллограмма измеряемого импульса. В процессе формирования осциллограммы в момент Tg времени с выхода линии 11 задержки на первые входы первого 9 и второго 10 стробоскопических преобразователей поступает импульс, что вызывает удержание на выходах первого 9 и второго 10 стробоскопических преобразователей напряжения, которое имелось на втором входе соответственно первого 9 и второго 10 стробоскопических преобразователей момента времени Tg. После окончания формирования импульсов на выходах блока 5 развертки выход первого 2 и второго 3 коммутаторов подключается к третьему входу, что обеспечивает поступление на второй и первый входы электронно-лучевой 4 трубки тех же напряжений, которые подавались в момент времени Tg. В результате течение паузы между периодами формирования осциллограмм на экране будет формироваться яркостная метка, находящаяся в момент времени Tg. При изменении задержки линии 11 задержки яркостная метка перемещается по линии осциллограммы. После поступления в момент времени Tg на первый и второй входы блока 1 отклонения разных по значению сигналов, равных соответственно Ub и Uc, в интервале после момента времени Tg и до момента времени Tg+T на выходе первого 9 стробоскопического преобразователя будет удерживаться сигнал, равный величине K•(Ub-Uc). Согласно формуле (2), если на входе интегратора 13 в течение времени T от момента времени Tg до момента времени Tg+T поддерживается сигнал, равный K•(Ub-Uc), то в момент времени Tg+T сигнал на выходе интегратора 13 изменится на величину Ub-Uc. В момент времени Tg сигнал на выходе интегратора 13 равен Uc; в момент времени Tg+T сигнал на выходе интегратора 13 изменился на величину Ub-Uc и стал равным Ub. Учитывая, что период следования измеряемых импульсов равен T, в моменты времени Tg+N•T сигнал, поступающий на первый вход блока 1 отклонения, равен Ub; N целое положительное число, N>0. В момент времени Tg+T сигналы на первом и втором входах блока 1 отклонения равны Ub, а сигнал на выходе равен нулю. После прихода в момент времени Tg+T импульса на первый вход первого 9 стробического преобразователя сигнал на выходе первого 9 стробоскопического преобразователя станет равным нулю. При нулевом сигнале на входе интегратора 13 сигнал на его выходе, согласно формуле (2), не изменяется и остается равным значению Ub, которое измеряется вольтметром 12. В моменты времени Tg+N•T сигнал на выходе блока 1 отклонения равен нулю, поэтому осциллограмма измеряемого импульса в моменты времени Tg+N•T пересекает центральную горизонтальную риску на шкале экрана, причем в месте осциллограммы, формируемом в моменты времени Tg+N•T, располагается яркостная метка. Момент начала развертки опережает момент времени Tg на время Tз задержки линии 11 задержки, что обеспечивает расположение яркостной метки на осциллограмме через время Тз от момента начала развертки, причем вольтметр 12 регистрирует напряжение на первом входе блока 1 отклонения в моменты времени Tg и Tg+T•N.From the bus 8 of the measured signal, the measured pulses are fed to the first input of the deviation unit 1. The signal Aa at the output of the deviation unit 1 is determined by the formula
Aa = K • (Ab-Ac), (1)
where Ab and Ac are the signal values at the first and second inputs of the deviation unit 1, respectively; K gain of the deviation unit 1. The signal from the output of the deviation unit 1 is fed to the first input of the first 2 switches and to the second input of the first 9 stroboscopic converter. From the synchronization bus 7, either synchronizing pulses or measured pulses are received at the input of the synchronization unit 6. The synchronization unit generates synchronization pulses, which from the output of the synchronization unit 6 are supplied to the inputs of the scan unit 5 and the delay line 11. The pulses from the output of the delay line 11 are supplied to the first inputs of the first 9 and second 10 stroboscopic converters. After each pulse received at the first input of the first 9 and second 10 stroboscopic converters, the signal that was at the second input at the time the pulse arrived at the first input is held at their output. When a pulse arrives at the input of the sweep unit 5, a sawtooth sweep pulse and a rectangular pulse are formed respectively at its first and second outputs, and the pulses at the first and second outputs have the same duration, in addition, the pulse beginnings at the first and second outputs coincide. The sawtooth pulse from the first output of the scanner unit 5 is fed to the first input of the second 3 switch and to the second input of the second 10 stroboscopic converter. The pulse from the second output of the scan unit 5 is fed to the second inputs of the first 2 and second 3 switches. The signal from the output of the second 10 stroboscopic converter is fed to the third input of the second 3 switch. The signals from the outputs of the first 2 and second 3 switches are supplied to the second and first inputs of the cathode ray 4 tube, respectively. In the presence and absence of a pulse at the second input of the first 2 and second 3 switches, their output is connected to the first and third inputs, respectively. The signal from the output of the first 9 stroboscopic converter is fed to the input of the integrator 13 and the third input of the first 2 switch. The signal Ae at the output of the integrator 13 is equal to

where Ar is the signal at the input of the integrator 13; S sign of the integral; T is the period following the measured pulses coming from the bus 8 of the measured signal; t is time. The signal from the output of the integrator 13 is fed to the input of the voltmeter 12 and the second input of the deviation unit 1. When a synchronization pulse arrives at the input of the synchronization unit 5 from its second output to the second inputs of the first 2 and second 3 switches, an impulse arrives, which for the duration of the sweep connects the outputs of the first 2 and second 3 switches to their first inputs. The scan pulse from the first output of the scan unit 5 through the second 3 switch is fed to the first input of the cathode ray 4 tube. The measured pulses received from the bus 8 of the measured signal are amplified by the deviation unit 1 and through the first 2 commutator are fed to the second input of the cathode ray 2 tube. As a result, an oscillogram of the measured pulse is formed on the screen of the cathode ray 2 tube. In the process of generating an oscillogram at time Tg, a pulse is received from the output of the delay line 11 to the first inputs of the first 9 and second 10 stroboscopic transducers, which causes the outputs of the first 9 and second 10 stroboscopic voltage converters to be held, which was present at the second input of the first 9 and second 10 stroboscopic time transducers Tg. After the formation of pulses at the outputs of the scanner unit 5, the output of the first 2 and second 3 switches is connected to the third input, which ensures that the same voltages supplied to the second and first inputs of the cathode ray 4 tube are supplied at the time Tg. As a result, during the pause between the periods of oscillogram formation, a brightness mark will be formed on the screen at the moment of time Tg. When changing the delay of the delay line 11, the luminance mark moves along the waveform line. After the deviation of signals of different values equal to Ub and Uc, respectively, at the time Tg to the first and second inputs of block 1, a signal equal to the value of the output of the first 9 stroboscopic transducer will be held in the interval after time Tg and until time Tg + T K • (Ub-Uc). According to formula (2), if a signal equal to K • (Ub-Uc) is maintained at the input of integrator 13 during time T from time Tg to time Tg + T, then at time Tg + T the signal at the output of integrator 13 will change by the value of Ub-Uc. At time Tg, the signal at the output of the integrator 13 is equal to Uc; at time Tg + T, the signal at the output of the integrator 13 changed by the value Ub-Uc and became equal to Ub. Considering that the period of the measured pulses is T, at times Tg + N • T the signal supplied to the first input of the deviation unit 1 is equal to Ub; N is a positive integer, N> 0. At time Tg + T, the signals at the first and second inputs of deviation unit 1 are equal to Ub, and the output signal is zero. After the arrival at time Tg + T of the pulse at the first input of the first 9 strobic converter, the signal at the output of the first 9 stroboscopic converter will become equal to zero. When the signal at the input of the integrator 13 is zero, the signal at its output, according to formula (2), does not change and remains equal to the value of Ub, which is measured with a voltmeter 12. At times Tg + N • T, the signal at the output of the deviation unit 1 is zero, therefore, the oscillogram of the measured pulse at times Tg + N • T crosses the central horizontal risk on the screen scale, and in the place of the waveform generated at times Tg + N • T, there is a brightness mark. The start time of the sweep is ahead of the time Tg by the delay time T3 of the delay line 11, which ensures the location of the brightness mark on the waveform after the time T3 from the start of the sweep, and the voltmeter 12 registers the voltage at the first input of the deviation unit 1 at the times Tg and Tg + T • N.

 Measurements are made as follows.

 By adjusting the delay of the delay line 11, the sweep coefficient and the deviation coefficient, the waveform of the measured pulse is located within the working part of the screen. To measure the amplitude of the measured pulse, a brightness mark is set at the top and at the base of the waveform of the pulse, while the readings Um and Uo of the voltmeter 12 are determined. To increase the accuracy of measurements of the amplitude of the measured pulse, it is possible to establish a deviation coefficient smaller than the ratio of the amplitude of the measured pulse to H , which reduces the masking effect of the waveform line. The amplitude of the measured pulse is Um-Uo. To measure the duration of the measured pulse by adjusting the delay time of the delay line 11, the luminance mark is set at the recession and the front of the oscillogram of the measured pulse, where the readings of the voltmeter 12 are equal to Ds and DF, respectively. The duration of the measured pulse is Ds-Df.

 Improving the measurement accuracy of the proposed device is due to the exclusion of the influence of the non-linearity of the transfer characteristic and the calibration error of the gain of the deviation unit 1 on the measurement error. This is explained by the fact that the voltmeter 12 measures the voltage equal to the input signal at a time corresponding to a point on the waveform marked with a brightness mark. Improving the measurement accuracy by reducing the masking effect of the waveform line provides the ability to measure the amplitude of the signal with a deviation coefficient less than the ratio of the amplitude of the measured pulse to size H, which improves the accuracy of choosing the location of the base and top of the measured signal.

Sources of information
1. G. Ya. Mirsky. Radio-electronic measurements. Moscow. "Energy". 1975 p. 136, fig. 3-21.

 2. Decision of the State Scientific and Technical Expertise of Inventions of June 21, 89 N 4492503 / 24-21 (132460) on recognition of a technical solution as an invention.

Claims (1)

 An oscilloscope containing a voltmeter, a deviation unit, two switches, a cathode ray tube, a scan unit, a synchronization unit, two stroboscopic converters and a delay line, the output of which is connected to the first inputs of the first and second stroboscopic converters, the inputs of the scanner and delay lines are connected to the bus synchronization, the first output of the scanner is connected to the first input of the second switch and the second input of the second stroboscopic converter, and the second output of the scanner is connected to the second the inputs of the first and second switches, the output of the second stroboscopic converter is connected to the third input of the second switch, the first and second inputs of the cathode ray tube are connected to the outputs of the second and first switches, respectively, the first input of the first switch and the second input of the first stroboscopic converter are connected to the output of the deviation unit, the first input of which is connected to the bus of the measured signal, characterized in that, in order to improve the accuracy of combining the brightness mark with the oscillogram, sheniya complexity measurements, improving the accuracy of measurements, introduced an integrator whose input is connected to the output of the first stroboscopic converter, and an output connected to the input of the integrator and a second input of the voltmeter deflection unit.