SU467361A1 - Voltage integrator - Google Patents

Description

one

This invention relates to a measurement technique.

Voltage integrators are known to study physical processes and are based on a push-pull integration method. They contain serially connected integrating amplifier and comparing device, keys, through the first switch the input of the integrator is connected to the input of the integrating amplifier, the input of the latter is connected via the second and third keys to the sources of reference voltages, a matching circuit, a time measurement circuit, a trigger equal to single, the output of which is connected to the control input of the first key.

To maintain such devices in a state of readiness for integration, at any time, keys are used to bypass the integrating capacitor and the amplifier input.

A significant disadvantage of such integrators is the dependence of the output on the magnitude and stability of the trigger threshold of the comparing device. The known methods of reducing the influence of the drift and the threshold value of the comparing device on the accuracy used in the integrating converters of digital voltmeters do not allow synchronizing the start of integration with the beginning of the physical process.

In order to improve accuracy, in the proposed integrator, the input of the first coincidence circuit is connected directly to the output of the comparing device, the input of the second coincidence circuit is via an inverter, the enabling inputs of the coincidence circuits are connected to the zero output of the trigger, and the outputs are connected

to the control inputs of the second and third keys.

FIG. 1 is a block diagram of the device; in fig. 2 - time diagrams of the device operation: a) output voltage

the integrating amplifier, b) the voltage at the output of the comparator, c) the times of the beginning of the -ti and the end of the tz of the first integration cycle, as well as the time interval T of the second integration cycle.

The integrator contains keys 1, 2, 3, an integrating amplifier 4, a comparison device 5, an inverter b, a matching circuit 7 and 8, a control trigger 9, a time measurement circuit 10, a time setting 11 and 12

integration.

The device works as follows. In the initial state, the trigger 9 is in the position at which the key 1 is open, the circuit 10 is blocked, on the coincidence circuit

filed resolving potential. Depending on the polarity of the voltage on the output of the comparison device t /, but the enabling current is fed through a coincidence circuit 7 or 8 to the control input of key 2 or 3, respectively. The input of the integrating amplifier is connected to the source of the reference voltage of the polarity, the integration of the voltage of which leads to the operation of the comparison device and the change in the polarity of the voltage t / but. For example, under the influence of the drift voltage of positive polarity at the input of the integrating amplifier, the voltage at its output reaches the lower threshold of the response of the C / psh comparison device at the output of the latter, and a positive polarity appears at which to the input of the integrating amplifier through switch 2 connects the source of the negative reference voltage (). This causes a change in the output voltage of the integrator in the opposite direction to the previous one. The voltage t / BbiXuy reaches the upper threshold of the comparison device operation (Surge voltage of the comparison device UNO changes its polarity, becomes negative, causing key 2 to close, and key 3 to open. Integration of voltage + Uy decreases C / V This sawtooth voltage reaches the level f / nn, the comparison device is triggered, the voltage L / HO again becomes positive, and the picture repeats.

At time ti, the bus 11 receives the impulse to start integrating the physical process and sets trigger 9 to the position at which key 1 closes, coincidence circuits 7 and 8 are blocked, keys 2 and 3 open. During the first clock cycle, the voltage Ux applied to the input of the device.

At time t, bus 12 receives a pulse of the end of integration of the physical process and sets trigger 9 to its initial state. The second beat begins. The key 1 is closed, the second time clock measurement circuit 10 is turned on, the resolving potential is supplied to the coincidence circuits 7 and 8. One of the keys 2 or 3 closes, automatically connecting to the input of the integrating amplifier a reference voltage of polarity opposite to the polarity of the input voltage.

Integration of selected voltage

continues for the second cycle until the time the comparator triggers. At this point, the time measurement circuit 10 is again blocked, the result recorded in it is proportional to the input voltage integral during the first clock cycle. At the same time, the process of compensating the drift of the integrating amplifier begins again.

In the pause between measurements, the voltage at the output of the integrating amplifier is maintained at the level of the triggering threshold of the comparing device with an accuracy determined by the difference between its upper and lower levels.

levels (sensitivity). This difference is easily minimized by using an amplifier with a large gain: phi: gain as a comparison device. TaiKHM way, the device is always

is ready to integrate the physical process and ensures high accuracy of the result, since the voltages at the output of the integrating amplifier at the beginning of the first cycle and at the end of the second cycle coincide.

In the proposed integrator, the result error is excluded due to the magnitude and instability of the trigger threshold of the comparing device. At the same time, the positive qualities of the known devices are preserved.

The integrator can be used in various fields of measurement technology, for example, for measuring the magnetic fields s of ring accelerators of charged particles.

Subject invention

Voltage integrator containing a series-connected integrator

the amplifier and comparing device, keys, through the first key, the input of the integrating amplifier is connected to the device input, and through the second and third keys - to sources of reference voltages, matched circuits, time measuring circuit, control trigger, whose single output is connected to the control input of the first key, about the fact that, in order to improve accuracy, the input of the first coincidence circuit

connected directly to the output of the comparing device, the input of the second matching circuit through the inverter, enabling the inputs of the matching circuits are connected to the zero output of the trigger, and the outputs are connected to the control inputs of the second and third keys.

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