SU556463A1 - Analog-discrete integrating device - Google Patents

Description

one

The proposed analog-discrete integrating device can be used in computing, in particular, in hybrid computing devices for long-term and precise integration of arbitrarily changing analog voltages.

Analog-to-digital integrators for use in computing are known, which include an analog integrator, comparators, and a reversible counter for accumulating integral 1.

The summation of the increments of the input voltage integral occurs when the output value of the analog integrator reaches a threshold value and then resets the analog integrator to zero. The implementation of this principle of operation leads to a rather complex structural scheme, since it requires the introduction of special nodes into it; clock generator, control counter, control device. In addition, this integrator has rather large errors due to the accumulation of the drift zero error and the loss of information about the input value during the reset time of the analog integrator to zero.

Analog-to-digital integrating devices are also known, which are used for long-term integration of signals taken from analog sensors, containing an analog integrator, threshold elements, an input signal polarity converter, analog keys, and a counter for accumulating integral 2. Such devices have limited use, since provide the ability to integrate sign-wired analog voltage.

The closest to the invention is an analog-discrete integrator, on the basis of which a device for measuring fluid flow is built, containing an integrator, the input of which is connected to the input of the device through the polarity conversion unit and the output to the inputs of the comparators whose outputs are connected to the logic element OR , the output of the OR gate is connected to the counting pulse driver, and a counter for accumulating the integration result 3.

However, this integrator cannot be used to integrate alternating analog voltages, since the counting device provides only the addition of electrical impulses. In addition, the scheme for the formation and prohibition of counting is rather complicated; it is based on the principle of comparing the period of pulse following with a given time. Here it is used that the frequency of the pulses generated at the outputs of the comparators is determined by the level of the input signal. Finally, in such an integrator, when the input signal is zero, the analog integrator comes to saturation due to its own zero drift, which causes errors and malfunctions, if not even consider the preparation mode. The purpose of the invention is to expand the range of integrable signals, as well as to increase the accuracy of the device. This is achieved by introducing into the analog-discrete integrating device a counting direction determining unit, two inputs of which are connected to the outputs of the comparators, and the output is connected to the first input of the counter, the second input connected to the first output of the former of the counting pulses, and the second output of this former is connected to the integrator control input, and a control trigger, the input of which is connected to the output of the OR logic element, and the output to the third input of the counting direction determination unit and the control input of the conversion unit Hovhan polarity. FIG. 1 and the block diagram of the proposed analog-discrete integrating device; FIG. 2 shows plots of analog voltages and digital signals explaining the operation of the device. The device contains (Fig. 1) an integrator 1 with an integrating capacitance discharge circuit, comparators 2 and 3, a polarity conversion unit 4, an OR 5 logic element, a control trigger 6, a counting direction determining unit 7, a counting driver 8 and a counter 9 to obtain in digital form the result of integrating the analog signal. FIG. 2 UVH-analog voltage at the operational input of unit 4; / a is the output voltage of the analog integrator 1. For simplicity, it is conventionally assumed that the time t of the analog integrator is sufficiently small and the input value t / Bx varies slightly over time; R, R — subtract and add instructions, respectively; Cr +, Cr- pulses of the Cr account at the output of the imager 8, which are to be recorded in counter 9; P is the discharge command of the integrator capacity of the analog integrator. The proposed device works as follows. The input signal enters the polarity conversion unit 4 of the input signal, which initially supplies this signal with its sign to the input of the analog integrator. Consider, for example, the case when, then the increment of the integral at the output of the integrator is positive; when the rising voltage at the output of the analog integrator reaches the field level threshold, a comparator 2 is triggered, which, through an OR 5 gate, trips the control trigger 6, and block 4 changes the sign of the integrand. This, in turn, causes a change in the sign of the increments of the integral at the output of the analog integrator, and the output and voltage tend to a negative level; when it is reached, the comparator 3 is triggered, which leads to the next change in the sign of the integrand. The increment of the integral at the output of the integrator becomes again positive, and the output voltage of the analog integrator tends to a positive threshold value. Thus, at a constant input value, comparators 2 and 3 operate strictly alternately. If at any moment the input value changes its counterpart, then the sign of the increment of the integral at the integrator output will also change; in this case, one of the comiarators will work twice a bit (Fig. 2). This information is used to determine the direction of the bill. The counting direction is formed by block 7, which implements the functions R, X () Xz y, R HoHs / XiX2, where ho is the command of the triggering trigger 6, which terminates the input to the integrator 1 of the analog signal with its own sign; Xi is the inverse value of Xo (), the command providing the change of sign of the integrand; X2, Xs - commands from the outputs of Comparators 2 and 3, respectively. The counting pulses Cr are formed by the shaper 8 counting pulses each time when the sign of the increment of the integral changes at the output of the analog integrator 1, i.e. when a comparator is set to the initial state after the next operation, and recorded in the counter 9. At the same time, depending on the counting direction counter implements the operation of addition of Cr + Cr-R, or subtraction. In the event that the input value is absent or commensurate with the drift voltage of the operational amplifier, the change in the output voltage of the analog integrator is determined by its drift characteristics. When the output integrator 1 reaches the threshold value of this or that sign, the corresponding comparator is triggered and switches the trigger 6, however, this does not cause a change in the sign of the output increment in the output section: In this case, the discharge commands of the integrator of the analog integrator are formed. Capacity is discharged by a small amount of ALa, such that

the output voltage of the analog integrator has become within its range; the comparator is then reset. Subsequently, the voltage at the output of the analog integrator changes in the manner described until an analog signal is produced at the input of unit 4.

The introduction of new nodes — a block for determining the direction of the bill and control, and its trigger — favorably distinguishes the proposed analog-discrete integrate, its device from the prototype, since it ensures the implementation of the reverse mode in the counter and, thus, the possibility of long-term integration of the analog-alternating analog voltages . In addition, the presence of the communication of the counting pulse generator with the control, its integrator input allows to increase the accuracy of the device in the field of small signals by using the information on the state of the comparators after switching the control of its trigger. As a result, the proposed device becomes very promising for use in hybrid computing.

The use of modern integrated circuitry has allowed to create a compact, highly reliable hybrid integrate, its device with high technical characteristics. Tests have shown that the accuracy of the device does not exceed 0.1% in the temperature range from 0 to + 60 ° C with an integration time of 7200 seconds and is resolved; its ability (minimum input signal) is ± 2 mV.

Claims (3)

1.Vavaev V.A., Malomot G.I. and Popova M.G. Analog-digital integrator with a long integration time. In the book. “Electronic technology in automation, vsusk 4, ed. “Soviet Radio, 1973. 2. Avt. St. No. 389515, cl. G 06G 7/18, 1973. 3.Robert J. Bamford, New Current Integrator, JEEE International Convention Record Part 10, 1966, p.p. 185-191. R