Bulletin of the Tomsk Polytechnic Institute named after S. M. Kirov, Holder of the Order of the October Revolution and the Order of the Red Banner of Labor

Vol. 221

1976

INFORMATION PROCESSING DEVICE

V. K. Zhukov, Yu. A. Kilin, I. I. Tolmachev

(Presented by the scientific and technical seminar of the Department of Information and Measurement Technology)

The device is intended for converting the amplitude of voltage pulses, as well as the ratio of the amplitudes of pulses arriving from two sources, into a signal suitable for recording by existing analog and digital means.

The input signal has the following parameters:

1. Amplitude of the measured pulse — 0–10 V.
2. Amplitude of the “probing” pulse — \((10 \pm 1)\) V.
3. Pulse duration — 3–5 microseconds at the 0.5 level.
4. Repetition frequency — 25–75 Hz.

The output signal of the device is presented in analog and digital forms. The analog signal has the form of trapezoidal pulses, which, with a small dynamic error, can be recorded on an H700 electromechanical oscilloscope using vibrators with a natural frequency of not less than 400 Hz.

The signal in digital form is represented by a binary-decimal code with weights 1, 2, 4, 8.

The output code is recorded by any digital printing device having at least three decimal digits and an operating speed of not less than 20 measurements per second.

The probing pulse \(U_{m1}\) and the pulse under investigation \(U_{m2}\) are fed, respectively, to storage devices SD1 and SD2 (Fig. 1).

SD1 and SD2 have the same block diagram and consist of a comparison circuit, an amplifier, and a diode-capacitor storage unit.

The pulse \(U_m\) applied to the input of the comparison circuit CC is compared in amplitude with the voltage \(U_c\) on the storage capacitor \(C_n\). The difference voltage \(U_m - U_c\), obtained from the comparison circuit, is fed to the amplifier, whose output signal is used to charge the storage capacitor. Thus, charging is carried out not from the amplitude of the pulse \(U_m\), but from a voltage-amplified pulse of amplitude \(k(U_m - U_c)\), which makes it possible to increase the steepness of the voltage rise at the converter output, since \(k(U_m - U_c)\) at the initial moment of charging significantly exceeds \(U_m\).

The pulse \(U_{m1}\), varying within small limits, is also fed to the monostable multivibrator MM1. MM2 is triggered by the trailing edge of MM1 and forms a pulse, by the trailing edge of which the trigger

Tr1 is switched to state “1”; in doing so, Tr1 delivers a voltage that switches on the pulse generator PG.

The PG generates signals whose amplitude is proportional either to the voltage \(U_{m1\text{av}}\) or to \(U_{m1}\), depending on the position of switch P1, which makes it possible, as will be shown below, to measure, respectively, the voltage \(U_{m2}\) or the voltage ratio \(U_{m2}/U_{m1}\).

The staircase-voltage generator SVG generates a voltage proportional to the number of pulses arriving at its input from the PG.

The comparison device CD operates at the moment of equality of the voltages at the outputs of the SVG and MU2, delivering a signal to input “0” of Tr1. The trigger changes to state “0” and switches off the PG.

The number of pulses that the PG has generated during one measurement is determined as

\[ N=\frac{1}{k_1}\frac{U_{m2}}{U_{\text{pg}}}, \]

where \(U_{m2}\) is the amplitude of the measured pulse; \(U_{\text{pg}}\) is the amplitude of the pulses at the PG output; and \(K_1\) is determined by the ratio of the value of the SVG voltage step to the PG output voltage: \(k_1=\Delta U_{\text{svg}}/U_{\text{pg}}\).

The value of the voltage \(U_{\text{pg}}\) depends on the operating mode of the device:

a) when measuring the value \(U_{m2}\), \(U_{\text{pg}}=U_{m1\text{av}}=\text{const}\), then

\[ N=\frac{U_{m2}}{K_1 U_{m1\text{av}}}=kU_{m2}, \]

i.e., it is proportional to \(U_{m2}\);

b) when measuring the ratio \(U_{m2}/U_{m1}\), \(U_{\text{pg}}=U_{m1}\), then

\[ N=\frac{1}{k_1}\frac{U_{m2}}{U_{m1}}, \]

i.e., it is proportional to the ratio of the amplitudes of the device’s input pulses.

The voltage \(U_{\text{pg}}\) is selected by means of switch P1.

The measurement result may be recorded by means of a digital printing device or a loop oscillograph, which is connected through a scaling converter to the SVG output.

The input signal of the digital printing device is a binary-coded decimal code obtained by means of pulse counter C from the sequential unit code arriving from the PG output in the form of a burst of pulses. Either every burst, every other burst, or every fourth burst of pulses may be fed to the input of C; this is obtained with division factors of the frequency of the investigated pulses by the frequency divider FD of 1, 2, and 4 times, respectively. The division factor is selected by switch P2 in accordance with the frequency of the investigated pulses and the response speed of the digital printing device. Trigger Tr2 is switched by a signal from FD to state “1” and opens switch K2. After a time equal to the duration of the pulse of MV2, the recorded burst of pulses begins to pass through K2 to C.

When a signal from CD arrives at input “0,” Tr2 changes to state “0,” closes switch K2, and, by means of the differentiating circuit DC, issues a pulse permitting readout of the information from the counter to the digital printing device. The counter is reset at each output pulse of FD through shaper F.

The information is reset from the storage capacitors of MU by switch K1 at the moment the conversion of the measured quantity into code is completed, and from the SVG capacitor by a pulse from MV1.

Fig. 1. Functional diagram of an information processing device