RU2010239C1 - Digital stroboscopic oscillograph - Google Patents

Abstract

FIELD: radio measurement technology. SUBSTANCE: digital stroboscopic oscillograph has synchronization unit 1, synchronized generator 3 of trains of pulses, pulse counter 4, analog delay unit 5, former 6 of strobe pulses, stroboscopic converter 7 of studied signal, analog-to-digital converter 9, three digital-to-analog converters 11, 13, 15, first register 16, indication controller 18, processor 19, CRT 20, interface wire 10. Novelty of oscillograph lies in insertion into it of quartz generator 21, frequency multiplier 22, stroboscopic converter 23 of calibrator, two commutator 2, 8, fourth and fifth digital-to-analog converters 12 and 14 and second register 17. Period of synchronized generator 3 of train of pulses is stabilized by signal which stability is determined by quartz generator 21. This leads to realization of higher accuracy of time-base sweep of signals. EFFECT: suppression of nonlinearity of delay in unit 5 with period of synchronized generator 3 of train of pulses. 4 cl, 15 dwg

Description

 The invention relates to radio engineering and is intended for registration, research and measurement of repetitive radio signals.

 Known stroboscopic oscilloscope with digital storage of instantaneous signal values, containing a synchronization unit, a synchronized pulse series generator, a stroboscopic converter, two pulse counters, two code comparators, two registers, a selector, a pulse number divider, an analog-to-digital converter (ADC), a digital storage unit , digital-to-analog converter (DAC), vertical deviation amplifier, cathode ray tube (CRT) [1].

 The disadvantage of this oscilloscope is that it is impossible to obtain a gating step of units and tens of picoseconds, since it is determined by the pulse period of the series. Modern counters and comparators allow you to work in the frequency range up to 1 GHz, so the described device can provide a step of approximately 1 gs and can be used to register signals with a maximum frequency of 500 MHz.

 The closest in technical essence to the claimed device is a 54120T digital stroboscopic oscilloscope of the Hewlett-Packard company [2] selected as a prototype, containing a synchronization block, a synchronized pulse series generator, two pulse counters, a register, a strobe pulse shaper, an analog delay block (BAZ) ), ADC, stroboscopic converter, three DACs, CRT, controller, processor, integrator, interface bus. The clock pulses from the output of the synchronization block are sent to the BAZ. The duration of the signal delay in the BAZ is determined by the corresponding DAC. The signal from the BAZ output starts the synchronized generator. In the initial state, using the register, the counters are set to the set value. After starting the pulse series generator, the counters count the number of pulses specified in the register and give out signals that allow the strobe pulse generator to start. At the output of the stroboscopic converter, a signal is generated proportional to the values of the signal under study at the time of the action of strobe pulses. This signal is encoded by the ADC and transmitted through the interface bus to the CRT controller, which converts the information into a form convenient for observation on the CRT screen. For each repetition period of the investigated signal, one of its values is encoded. To change the gating moment, the processor through the interface bus loads the new delay code value into the register and DAC, after which the process of sampling the signal is repeated.

The disadvantage of the prototype is the significant nonlinearity of the time base of the signals, especially in the picosecond range of duration. This is due to the fact that it is impossible to produce a BAZ with an ideal linear code-delay characteristic. In addition, the periods of the synchronized pulse series generator are unstable. The first period is especially different from the stationary value, since transients in the generator have not yet been established. As a result of this, the error analysis signal of the 54120T oscilloscope is 10 ^-3 T _x + 10ps (T _x is the duration of the measured interval).

 The technical problem that is solved by the invention is to reduce the error in the analysis of the studied signals due to the automatic adjustment of the frequency of the synchronized pulse series generator and the delay time in the BAZ according to the signal with a stable period obtained by using a frequency multiplier of the crystal oscillator.

 The distinguishing features of the inventive digital stroboscopic oscilloscope (ЦСО), containing a synchronization unit, the first input of which is an input of a clock signal, a synchronized series of pulses, the output of which is connected to a counting input of a pulse counter, BAZ, a strobe generator, the first output of which is connected to a trigger input of a stroboscopic converter of the studied signal, the first input of which is the input of the oscilloscope, while the control inputs of the synchronization unit, BAZ, stroboscopic the converter of the signal under study and the pulse counter are connected respectively to the outputs of the first, second and third DACs and the first output of the first register, the inputs of which are connected to the interface bus, also connected to the ADC output and the inputs of the processor and display controller, the output of which is connected to the CRT, are the introduction a quartz oscillator, a frequency multiplier, a stroboscopic converter of the calibrator, the first and second switches, the second register, the fourth and fifth DACs, and the special implementation of the BAZ is formed a strobe pulse generator, a synchronized pulse series generator.

 In FIG. 1 presents a block diagram of the inventive CSO; in FIG. 2 - BAS; in FIG. 3 - shaper strobe pulses; in FIG. 4 - synchronized generator; in FIG. 5 - switch; in FIG. 6 shows the algorithm of the processor; in FIG. 7 - a control algorithm for the "level" of synchronization at the command of the operator; in FIG. 8 - algorithm for controlling the "offset" of the strobe converter of the signal under investigation; in FIG. 9 - algorithm for recording the implementation of the investigated signal; in FIG. 10 - algorithm for sampling the signal with number i; in FIG. 11 is an algorithm for taking a reference sample of a signal; in FIG. 12 is an algorithm for identifying non-linearity of BAS and determining coordinates (delay codes) of reference samples; in FIG. 13 is an algorithm for computing arrays of scan codes; in FIG. 14 is a correction algorithm for a period of a synchronized pulse series generator; in FIG. 15 is an algorithm for adjusting the magnitude of the maximum delay BAZ.

 DSS (Fig. 1) contains a serially connected synchronization unit 1, a first switch 2, a synchronized generator 3 series of pulses, a counter 4 pulses, a BAZ 5, a shaper 6 strobe pulses, a stroboscopic converter 7 of the signal under study, the second switch 8, ADC 9. Input the start of the ADC is connected to the second output of the strobe pulse shaper 6, and the output to the interface bus 10 connected to the digital inputs of the DAC 11 (third), 12 (fourth), 13 (second), 14 (fifth), 15 (first), registers 16 (first), 17 (second), display controller 18 and rotsessora TSAP11 19. Outputs 13 and 15 are respectively connected to the stroboscopic converter control inputs 7, BAZ 5 and 1 sync block. The outputs of the DACs 12 and 14 are connected respectively to the input of the adjustment of the reference voltage of the second DAC 13 and to the input of the adjustment of the synchronized generator 3 series of pulses. The outputs of the first register 16 are connected first to the control input of the counter 4 pulses, the second to the stop input of the synchronized generator 3 series of pulses. The output of the second register 17 is connected to the control inputs of the switches 2 and 8. The output of the display controller 18 is connected to the CRT 20. The second output of the crystal oscillator 21 is connected to the first input of the switch 2, and its first output is connected to the input of the frequency multiplier 22. The output of the frequency multiplier is connected to the signal input of the stroboscopic converter 23 of the calibrator, the start input of which is connected to the third output of the shaper 6 of the strobe pulses, and the output to the first input of the switch 8.

 BAZ 5 (Fig. 2) contains a buffer stage 24, the input of which is the start input of the BAZ 5, and the output is connected to the inputs of the driver 25 of the start pulses, the output of which is the second input of the BAZ 5, and the limiter 26. The output of the limiter 26 through a resistor 27 is connected to the output of the controlled current source 28, the input of which is the control input of the BAZ 5, and with the anode of the diode 29, which is the first output of the BAZ 5. The cathode of the diode 29 is grounded.

 The strobe pulse generator 6 (Fig. 3) contains a serially connected latch 30, a buffer cascade 31, and an end driver 32. The output of each of these cascades are the first, second, and third outputs of the former 6, respectively.

 The synchronized generator 3 series of pulses (Fig. 4) contains a series-connected D-flip-flop 33, OR gate 34, capacitor 35 and varicap 36, the cathode of which is grounded, and the anode is the tuning input of generator 3. Between the first input of OR gate 34 and its output included line 37 delay. The C-input of the D-flip-flop 33 is the input of the start of the generator 3, the D-input is the input of the logic level “1”, and the R-input is the input of the stop. The output of the OR gate 34 is the output of the generator 3.

 Switches 2 and 8 (Fig. 5) can be made on the relay REC-11 according to the attached circuit diagram.

 As DACs 11, 12, 13, 14, 15, microchips of the KR572PA2A type were used in a typical inclusion, as shown in Fig. 6.83 in [6], and registers 16, 17 on 533IR22 microcircuits. A crystal oscillator 21 and a frequency multiplier 22 are described in [5]. Functional circuits of synchronization unit 1 and stroboscopic transducers 7, 23 are described in [3] in Fig. 5.1 and 3.3. CRT 20, 4 pulse counter, ADC9, interface bus 10, processor 19, display controller 18 are similar to the prototype and are presented in [2] on pages 6B-25-6B-30.

 CSO works as follows.

When registering the signals, the switches 2 and 8 are turned on so that the signal from the synchronization unit 1 is fed to the input of the synchronized generator 3 series of pulses, and the signal from the output of the strobe converter 7 of the signal under investigation is input to the ADC 9. Under the influence of the clock signal, the synchronized generator of 3 series of pulses starts to generate pulses with a period T. After the counter 4 pulses counts the specified number of pulses, set in the first register 16, the BAZ 5 starts. The delay value in the BAZ 5 is determined by the signal of the second DAC 13. The maximum the delay value corresponds to the duration of the period T. The signal from the output of the BAZ 5 triggers the strobe-pulse generator 6, the outputs of which generate strobe-pulses for the stroboscopic converter 7 researched signal calibrator stroboscopic converter 23 and the ADC 9. The start pulse strobe pulses gated analyzed strobe signal at input of the signal converter 7, and is formed at its output an analog voltage proportional to the values of the signal at the gating. This value is encoded by the ADC 9 and transmitted via the interface bus 10 to the display controller 18. After completing one sampling cycle, the processor 19 loads the new delay code value into the first register 16 and the second DAC 13 and the cycle repeats. Thus, the signal is recorded in the memory of the display controller 18 at predetermined intervals. The controller 18 displays displays information on the screen of the CRT 20 for visual viewing. To eliminate the error caused by the imperfection of the synchronized generator of 3 series of pulses and BAZ 5, the central control center switches to calibration mode. To this end, at the command of the processor 19, the second register 17 is set to a state that switches the switches 2, 8 and connects to the input of the synchronized generator 3 series of pulses of the second output of the crystal oscillator 21, and to the first input of the ADC 9 of the output of the stroboscopic converter 23 of the calibrator. The signal from the frequency multiplier 22 with a stable period is fed to the input of the stroboscopic converter 23 of the calibrator. According to the instructions of the processor 19, the known time intervals are measured corresponding to an integer number of signal periods from the output of the frequency multiplier 22. The data obtained are used to calculate and record digital codes in the DACs 12 and 14 to correct the period T of the signal from the output of the synchronized generator 3 of the pulse signals and adjust the value of the maximum delay BAZ 5. To obtain large time delays, long durations of the maximum delay equal to T _max = 2 ˙T ^M, where M - the number of bits of the counter 4 pulses used shutdown mode generator 3 synchronous pulse trains from the CPU 19. When the proper delay greater than the maximum delay, then after trobirovaniya CPU 19 gives a stop command, synchronous generator 3, a series of pulses to the first register 16 and writing information from the ADC 18 to the controller 9 displays. In this mode, the counter 4 pulses cyclically gives the start pulses BAZ 5 with a period of T _max . The calculation of these periods is carried out by the processor 19. Upon reaching the predetermined delay value, a signal is supplied to the first register 16, which turns off the synchronized generator 3 of a series of pulses and writes a new delay code to the 4 pulse counter. Since the period of the synchronized generator 3 of a series of pulses is stabilized by a signal whose stability is determined by the crystal oscillator 21, it is possible to realize significantly greater accuracy of the time base of the signals. The proposed scheme allows to eliminate the nonlinearity of the delay in the BAZ 5 with the period of the synchronized generator 3 series of pulses. Correction of nonlinearity is as follows. The delay codes are determined that correspond to the given periods of the signal of the frequency multiplier 22 (C _{1 ...} C _n ), then the non-linear dependence of the control codes on the delay of the quadratic curve is approximated (the coefficients of the polynomial a _o , a ₁ , a _{2 are} determined) and the codes providing the required delay t _s [s (t _s ) = a _o + a ₁ (t _s ) + a ₂ t ₃ ].

 The presence in the BAZ 5 of the external generator start output allows you to have less instability in the external synchronization mode of the pulse generators. Less instability is obtained during sweeps shorter than the maximum delay of the BAZ 5 and is due to the smaller number of active elements in the trigger circuit of the stroboscopic transducer 7 of the investigated signal relative to the start of the external generator.

 Due to the presence of the input adjustment in the second DAC 13 is possible to adjust the reference voltage. Adjusting the reference voltage provides compensation for the instability of the maximum delay value caused by temperature changes in the BAZ 5.

1 +

, где i_обр= Е_обр/R; i - величина тока рассасывания заряда;
Е_обр - напряжение ограничения в ограничителе 26.BAZ 5 works as follows. The signal from the output of the second DAC 13 is supplied to a controlled current source 28 with a large output resistance. The current from the current source 28 flows through the diode 29 with the accumulation of charge and creates an excess charge in it Q = i τ _W , where i is the current value; τ _W - carrier lifetime. When starting BAZ 5, the buffer cascade 24, which is a waiting multivibrator [4, Fig. 6.1], produces a pulse of a fixed duration. The pulse absorbs excess charges and closes the diode 29. The diode blocking delay time, equal to the charge absorption time, is determined by the expression
t ₃ = τ _w ln

1 +

where i _arr = E _arr / R; i is the magnitude of the charge resorption current;
E _arr - voltage limit in the limiter 26.

When using diodes 29 with the accumulation of charges of the type KD630, the maximum delay can reach 80-100 ns. Shaper 25 start pulses provides the formation of a signal at the second output of the BAZ 5 with the required amplitude and duration. The limiter is designed to stabilize the voltage E _arr , which determines the reverse current of the diode 29, and is made on a Schottky diode, to one of the terminals of which a stable voltage source is connected.

 The strobe pulse generator 6 (Fig. 3), using the lock 30, which is a multivibrator, captures the moment the output signal BAZ 5 intersects a given voltage level and generates a pulse with a stable amplitude (the signal from the output of the BAZ 5 decreases in amplitude with increasing delay). The signal from the output of the latch 30 starts the stroboscopic converter 7 of the studied signal and through the buffer stage 31, which is an emitter follower, the end driver 32. In addition, the signal from the output of the buffer stage 31 starts the ADC 9. The terminal driver 32 captures the start pulses of the stroboscopic converter 23 of the calibrator and made according to the scheme presented in [3] in Fig. 2.11.

 The synchronized generator 3 series of pulses (Fig. 4) works as follows. With the arrival of the synchronization pulse from block 1 through the switch 2 to the C-input of the D-flip-flop 33, a logic level “0” is formed at its output. The OR gate 34 starts to switch with a period corresponding to the duration of the delay in the delay line 37. Adjusting the period within small limits, compensating for temperature changes in the period of oscillation, is carried out by changing the capacitance of the varicap 36 connected to the output of the OR gate 34 through the capacitor 35. The synchronized generator 3 is turned off by supplying a logic level of “0” to the R-input of the D-trigger 33.

The inventive DSC has a period T of a pulse series generator equal to 49 ns. The frequency of the signal from the output of the frequency multiplier 2 GHz. To correct the non-linearity of the delay, 80 values of the signal periods from the output of the frequency multiplier were measured in the BAS. The adjustment of the period of the synchronized generator and the correction of the nonlinearity of the delay of the BAS allowed us to obtain errors in the analysis of the signal DSS 10 ^-5 T _x + 5ps, that is, to reduce by more than an order of magnitude in comparison with the prototype. In addition, the instability of the synchronization of the pulse generator at time intervals up to 40 ns does not exceed 1 ps (rms value. For the prototype (HP54120T), this parameter is 2 ps.

 A description of the algorithms for controlling the operation of the blocks of the DSP processor 19 is given below.

 In FIG. 6 shows the main algorithm of the processor 19, which determines the operation of the device as a whole. After turning on the power, during the initial installation, the processor performs such typical actions as self-monitoring, checking the health of the display controller, setting the compensation voltages (third DAC) to the initial state, and the synchronization level (first DAC). Further, until the power is turned off, the processor performs two main functions: it responds to operator commands by performing certain subroutines, and provides cyclic sampling (samples) of signals.

 In FIG. 7 shows the algorithm for controlling the "level" of synchronization at the command of the operator. The current "level" value is stored in the LEVEL memory location. First, the direction of the “level” change is determined - increase or decrease. Then the current “level” value is compared with the lower or upper limit value. If the parameter "level" can exceed the permissible limits, an error message is issued and the previous value of the "level" is saved. If the parameter value does not go beyond, then the content of the LEVEL memory cell increases (or decreases), and then the changed “level” value is written to the DAC 15. The new “level” value is also displayed on the CRT screen in alphanumeric for visual observation by the operator.

 In FIG. Figure 8 shows the control algorithm for the "offset" of the stroboscopic converter of the signal under investigation. The current offset value is stored in the OFS memory location. The bias control is performed by writing the contents of the OFS cell to the DAC 11. Otherwise, the algorithm in FIG. 8 is similar to the algorithm in FIG. 7.

. Затем процессор 19 записывает в регистр 17 логическую "1", включается режим "калибровка". При этом генератор 3 синхронизируется от кварцевого генератора 21, а на вход АЦП 9 поступает сигнал с выхода стробоскопического преобразователя 23 калибратора. Выполняется взятие трех опорных выборок сигнала калибратора КС: RP1, RP2, RP3. На основе анализа опорных выборок RP1, RP3 выполняется коррекция периода Т синхронизируемого генератора 3 путем вычисления и записи в ЦАП 14 кода коррекции. На основе анализа опорных выборок RP1, RP2 выполняется коррекция максимальной задержки БАЗ 5 путем вычисления соответствующего кода и записи в ЦАП 12. После этого заключается режим "калибровка", процессор 19 записывает в регистр 17 логический "0", при этом генератор 3 синхронизируется от внешнего синхросигнала, а на вход АЦП 9 подается сигнал с выхода стробоскопического преобразователя исследуемого сигнала. Цикл регистрации исследуемого сигнала повторяется.In FIG. 9 shows an algorithm for registering the implementation of the signal under investigation. It is mainly composed of sampling blocks similar to the block in FIG. 6. From a comparison of these blocks, it follows that between the blocks in FIG. 9, any operator commands may be executed. However, since these commands do not affect the sequence and internal completion of the blocks in FIG. 9, and their appearance is random in time, the blocks of the execution of the operator's instructions in FIG. 9 are absent. First, N samples of the studied signal siG (i), i =

. Then the processor 19 writes a logical "1" to the register 17, the "calibration" mode is activated. When this generator 3 is synchronized from the crystal oscillator 21, and the input of the ADC 9 receives a signal from the output of the stroboscopic converter 23 of the calibrator. Three reference samples of the KS calibrator signal are taken: RP1, RP2, RP3. Based on the analysis of the reference samples RP1, RP3, the period T of the synchronized generator 3 is corrected by calculating and writing the correction code to the DAC 14. Based on the analysis of the reference samples RP1, RP2, the maximum delay of the BAZ 5 is corrected by calculating the corresponding code and writing to the DAC 12. After this, the "calibration" mode is entered, the processor 19 writes a logical "0" to the register 17, and the generator 3 is synchronized from the external clock signal, and the input of the ADC 9 receives a signal from the output of the stroboscopic converter of the signal under study. The cycle of registration of the investigated signal is repeated.

 In FIG. 10 shows an algorithm for sampling a signal with a number that is identical to the algorithm of the prototype. The delay value, which determines the temporal position of the signal sampling, is set by digital codes recorded in the DAC 13 and in register 16. These digital codes SWA (i) - the code that controls the BAZ, and SWD (i) - the code that controls the counter 4, are calculated in advance and stored in processor memory in the form of arrays of dimension N, where N is the number of scan points. The calculation of these arrays is carried out according to the algorithm shown in FIG. 13, when changing the sweep parameters of the oscilloscope (sweep time, initial delay). After counter 4 and BAZ 5 work out the specified delay, the stroboscopic converter will take a sample of the signal, the ADC converts the voltage value into a digital code, which is stored in the SIG (i) memory cell.

 The reference sampling algorithm of the signal of the calibrator RPi shown in FIG. 11 is similar to the previous one. The delay codes RAi, RDi, i = 1.3, are also computed in advance.

 To calibrate the sweep of the oscilloscope, a signal with a known period T is used, generated by the frequency multiplier 22 from the signal of the oscillator 21 with quartz frequency stabilization. The possibility of sampling this signal is provided by the introduced stroboscopic converter 23 of the calibrator and the first and second switches 2 and 8, as well as register 17. The calibration of the oscilloscope sweep is as follows.

 1. Identification of nonlinearity of the BAS (calculation of coefficients of approximating polynomials). The determination of the coordinates of the reference samples (performed once after turning on the device).

 2. Correction of the nonlinearity of the BAS. It is performed when calculating the sweep array SWA (i) using the obtained polynomial coefficients.

3. The correction of the period T of the signal of the synchronized generator 3 and the maximum delay BAZ τ _max . It is carried out after registration of each implementation of the studied signal or at certain intervals.

WA_макс(i-1)/(N-1)

В четвертый и пятый ЦАП записываются управляющие коды, равные половине максимальных. Поскольку идентифицируется нелинейность БАЗ, то код задержки счетчика 4 равен нулю для всех выборок сигнала, а код задержки БАЗ линейно возрастает от нуля для первой выборки сигнала до максимального значения SWA_макс для последней выборки.In FIG. 12 shows an algorithm for identifying BAS nonlinearity and determining coordinates (delay codes) of reference samples. First, an array of linear delay codes is formed.

WA _max (i-1) / (N-1)

In the fourth and fifth DACs, control codes equal to half the maximum are written. Since the non-linearity of the BAZ is identified, the delay code of the counter 4 is zero for all samples of the signal, and the delay code of the BAS linearly increases from zero for the first sample of the signal to the maximum value SWA _max for the last sample.

. На выходе умножителя 22 частоты имеется синусоидальный биполярный сигнал с периодом

. Полученный сигнал RP(i) искажен за счет неэквидиcтантности моментов взятия его выборок. Обработка массива значений RP(i) заключается в локализации моментов перехода значений сигнала через ноль t_o, t₁, . . . , t₁и определении соответствующих этим моментам кодов задержки С_о, С₁, . . . , C_L. Направление SD первого перехода через ноль фиксируется, и далее принимаются во внимание только переходы того же направления. SD= + 1, если переход положителен, SD= -1, если отрицателен.Next, the “calibration” mode is turned on and the implementation of N samples of the calibrator signal RP (i), i =

. At the output of the frequency multiplier 22 there is a sinusoidal bipolar signal with a period

. The received signal RP (i) is distorted due to the non-equidistance of the moments of taking its samples. Processing the array of values of RP (i) consists in localizing the moments of transition of the signal values through zero t _o , t ₁ ,. . . , t ₁ and determining the corresponding delay codes C _o , C ₁ ,. . . , C _L. The direction SD of the first zero crossing is fixed, and only transitions in the same direction are taken into account. SD = + 1 if the transition is positive, SD = -1 if it is negative.

The number of periods of the calibrator signal corresponding to the change in the delay in the BAS from τ _min (SWA = 0) to τ _max (SWA = SWA _max ) is L (the number of zero crossings +1). L must be large in order to get enough information about the nonlinearity of the BAS. At the same time, the number of samples per period of the N / L calibrator signal must be at least 15-20 (otherwise, the localization accuracy of the moment the signal passes through zero decreases and the error of correction of the nonlinearity of the BAZ increases). In the claimed CSO L = 80.

To correct non-linearity, the entire delay range of the BAS is divided into non-overlapping sections
t _o . . . . t ₁ . . . t ₂
t ₂ . . . t ₃ . . . t ₄
t ₄ . . . t ₅ . . . t ₆
. . . . . . . . . . .

t _L-2 . . . t _L-1 . . . t _L limited by the "zeros" of the calibrator signal.

;
a $\genfrac{}{}{0ex}{}{\text{1}}{\text{2}}$ =

.For the first section, the coefficients of the approximating polynomial are calculated:
a _o ⁽¹⁾ = C _o ;
a $\genfrac{}{}{0ex}{}{\text{1}}{\text{1}}$ =

;
a $\genfrac{}{}{0ex}{}{\text{1}}{\text{2}}$ =

.

;
a $\genfrac{}{}{0ex}{}{\text{(}}{\text{2}}$ ^k)=

.Then, the coefficients a _o ^{(k) are} determined similarly; a ₁ ^(k) , a ₂ ^(k) for the remaining sections with numbers k = 2.. . L / 2:
a _o ^(k) = C _{2 (k-1)} ;
a $\genfrac{}{}{0ex}{}{\text{(}}{\text{1}}$ ^k) =

;
a $\genfrac{}{}{0ex}{}{\text{(}}{\text{2}}$ ^k) =

.

After that, the value of the first zero delay t _{o of the} calibration signal is determined. To do this, extrapolation is carried out to the left of the first section (for example, according to the Newton method using the coefficients a _o ⁽¹⁾ , a ₁ ⁽¹⁾ , a ₂ ⁽¹⁾ .

На фиг. 13 изображен алгоритм вычисления массивов кодов развертки с кусочно-квадратической аппроксимацией нелинейной зависимости задержки БАЗ от кодов управления.The following values are used as the coordinates of the reference samples

In FIG. 13 shows an algorithm for computing arrays of scan codes with a piecewise-quadratic approximation of the nonlinear dependence of the delay of the BAS on the control codes.

The input data are the number of samples N, the initial delay τ, and the sweep step Δt. The program is executed cyclically for delay codes with numbers from 1 to N. First, the total delay time t _i for the sample with number i is determined. Then, a part of the delay t _o (i), which is a multiple of the period T of oscillations of the synchronized generator 3, is extracted, the counter control code SWD (i) 4 is calculated and stored. From the remainder t _{A (i)} <T, the delay value of the first zero t _o is subtracted and the number k the approximation section, and then using the coefficients a _o ^(k), a ₁ ^(k) , a _o ^(k) , the code BAS (delay control) BAZ is calculated and stored.

 In FIG. 14 shows an algorithm for correcting the period T of a synchronized generator of 3 series of pulses. First, the difference between the values of the third and first reference samples of the calibrator signal is calculated. The time interval between these samples is T. If the value of T is a multiple of the period of the calibration signal, then the difference Δ is equal to zero. If T differs from the required value, then Δ is nonzero. Since the reference samples are taken from the signal near the intersection of zero, that is, in the area with maximum steepness, the highest sensitivity of the conversion of the time shift to voltage is provided.

 The direction of correction (increase or decrease of the correction parameter STD stored in the processor memory) depends on the sign Δ and on the sign SD of the slope of the signal at the moment of zero crossing. If these signs coincide, then the change in the parameter is negative, if opposite, positive. After calculation, the value of the STD is recorded by the processor 19 in the DAC 14, which adjusts the period T of the generator 3.

(L-1). Коды задержки RA₁= C_o, RA₂= C_L определяются при калибровке, и если за прошедшее с момента калибровки времени характеристики БАЗ не изменились, то разность Δ = RP2= RP1 равна нулю. Если задержка τ_макс увеличилась или уменьшилась по сравнению с первоначальной, то изменилось значение задержки, соответствующее кодам RA₁, RA₂, и Δ отлична от нуля. По аналогии с предыдущим алгоритмом определяется знак регулирования. Вычисленная величина параметра СТА записывается в четвертый ЦАП, что приводит к изменению временного масштаба БАЗ.In FIG. 15 shows an algorithm for adjusting the value of the maximum delay BAZ 5. The algorithm is similar to the previous one. The difference in the values of the second and first reference samples characterizes exclusively BAZ, since the time interval between these samples is the interval between the first and last zeros of the calibration signal, equal to

(L-1). The delay codes RA ₁ = C _o , RA ₂ = C _{L are} determined during calibration, and if the BAS characteristics have not changed since the time of calibration, then the difference Δ = RP2 = RP1 is equal to zero. If the delay τ _max increased or decreased compared with the original, then the delay value corresponding to the codes RA ₁ , RA ₂ , and Δ is different from zero. By analogy with the previous algorithm, the sign of regulation is determined. The calculated value of the CTA parameter is recorded in the fourth DAC, which leads to a change in the time scale of the BAS.

In FIG. 12 shows that during calibration, the parameters CTA and CTP are assigned values equal to half the maximum. The tuning range T and τ _{max is} set so that it is possible to compensate for any changes in these parameters caused by various disturbing factors within the permissible operating conditions of the oscilloscope. (56) 1. USSR Copyright Certificate N 911342, cl. G 01 R 13/20, 1982.

 2. HP54120T Digitising oscilliscope - Service Manual Henletl-Packord, 1988 (Fig. 6B-25-6B-30).

 3. Ryabinin Yu. A. Stroboscopic oscillography. M.: Sov. radio, 1978.

 4. Reference pulse technology. / Edited by V. M. Yakovlev, Kiev: Technique, 1970.

 5. Equipment for frequency and time measurements. / Ed. A.P. Gorshkova, M.: Sov. radio, 1971, p. 73.

 6. Analog and digital integrated circuits. / Ed. S.V. Yakubovsky. M.: Radio and Communications, 1984, p. 356.

Claims (4)

 1. Digital sampling oscilloscopes, sodepzhat Synchronizing unit, pe.pvyy koto.pogo input is input sinhposignala ostsillogpafa, sinhponizipuemy of generators sepy pulses output koto.pogo counting input connected to the pulse counter, the delay the analogue block, fopmipovatel stpobimpulsov, pe.pvyy koto.pogo input connected to the input trigger signal stpoboskopicheskogo Transmitter issledumogo the first input of which is the input of the oscilloscope, while the control inputs of the synchronization block, the analog delay block, stroboscopic the converter of the signal under study and the pulse counter are connected respectively to the outputs of the first, second, third digital-to-analog converters and the first output of the first register, the digital inputs of which are connected to the interface-to-analog-to-analog-to-analog-to-analog output an electron beam tube, characterized in that a quartz oscillator, a frequency multiplier, a stroboscopic converter of the calibrator, a first and second switch are introduced into it Ora, the second register, the fourth and fifth digital-to-analog converters, in this case, the first output of the quartz generator is connected to the input of the frequency multiplier, the second - with the first input of the first switch, the second input of which is connected to the sync , the output of the frequency multiplier is connected to the signal input of the stroboscopic converter of the calibrator, the output of which is connected to the first input of the second switch, with the output of the stroboscopic converter being studied with the needle is connected to the second input of the second switch, the output of which is connected to the first input of the analog-to-digital converter, the inputs of the start of the analog-to-digital converter and the stroboscopic converter of the calibrator are connected respectively to the second and second outputs the output of which is the external trigger output of the oscilloscope, and its trigger input is connected to the pulse counter output, the digital inputs of the fourth and fifth digital alogovyh Transmitters and vto.poy registers connected to intepfeysnoy bus outputs fourth-and fifth tsifpoanalogovyh Transmitters are respectively connected to the inputs podstpoyki opopnogo STRESS vto.poy tsifpoanalogovogo Transmitter and input podstpoyki sinhponizipuemogo of generators sepy pulses input stop koto.pogo connected to the second type of output of first registers, and the output vto.poy registers connected to the control inputs of the first and second switch.  2. The oscilloscope according to claim 1, characterized in that the analog delay block contains a buffer stage, the input of which is the input of the start of the block, the pulse generator of the start, the output of which is the second output of the block, the limiter, the controlled current source, the input of which is the input of the control and a diode with accumulation of charge, the cathode of which is connected to the ground bus, and the anode to the output of the limiter through the resistor and to the output of the controlled current source, being the first output of the unit, the output of the buffer stage is connected to the limiter and opmipovatelem start pulses.  3. The oscilloscope according to Claim 1, characterized in that the strobe generator comprises consecutively connected latch, buffer cascade, terminal former, and the outputs of each of the blocks are the first, second, and third outputs of the former.  4. The oscilloscope according to claim 1, characterized in that the synchronized pulse generator contains a D-flip-flop, a delay line, an OR logic element, the output of which is the output of the generator, and the varicap, the cathode of which is connected to the common bus and the anode is a generator, connected through a capacitor to the output of the OR logic element, and a delay line is connected between this output and its first input, the second input of the OR logic element is connected to the output of the D-trigger, the C-input of which is the generator start input, and the P-input is the input stay Sheep Generator.

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