SU884076A1 - Dc amplifying device - Google Patents

Description

   .one . The invention relates to radio engineering and can be used in radio measuring devices. A DC gain with drift-zero correction is known, comprising two amplification channels and a summing cascade 1. Such an amplifier permits errors in the transmission of the input signal. The closest technical solution to the invention is a direct current amplifying device comprising an operational amplifier with a negative feedback circuit, the inverting input and output of which are connected respectively to the input and output of the device and the sensation channel .2. However, this device has a low accuracy of zero drift compensation. The purpose of the invention is to reduce the drift of faults. For this purpose, in the device for amplifying the direct current, the inverting input of the operational amplifier is connected through the first disconnecting switch, the first memory element, connected in series. and the second disconnecting key is connected to the output terminal of the computational channel, the connection point of the first disconnecting key and the first memory element is connected to the input terminal of the compensation channel, and the connection point of the second disconnecting key and the first memory element with the non-inverting input of the operational amplifier made in the form of an inverting amplifier, the output of which is connected to the common bus of the device, through a third interlocking key connected in series, the second The memory element and the fourth lock key, the connection point of the third lock key and the second memory element are connected to the input of the inverting amplifier, and the connection point of the fourth lock key and

The second storage element is with the input of the compensation channel, the output of which is the inverter output of its amplifier.

 The drawing shows a circuit diagram of the proposed device.

The DC gain device contains an operational amplifier (OA) 1, a negative feedback circuit 2, the first 3 and second 4 trip switches, the first storage element 5 and the compensation channel 6 containing the inverting amplifier 7, the second storage element 8, the third

9 and fourth 10 closing keys, reference generator I.

The device works as follows.

In the first measure, the opening keys 3 and 4 are closed, the closing keys 9 and

10 open. Drift zero is determined mainly by the drift zero of the inverting amplifier 7, and the effect of the drift zero OA 1 is negligible, because it is weakened K times. The first memory element 5 is included in the negative feedback circuit of the inverting amplifier 7 and simultaneously between the inputs of the op-amp 1. When there is a circuit 2, the potentials are applied to the inputs of the op-amp 1, the difference of which is equal to the zero offset of the op-amp 1, and accordingly the first element is charged memory 5, the inclusion of which in the negative feedback circuit allows for stable operation of the circuit with a large K factor. In the second cycle, the opening keys 3

and 4 are open, and the closing ends of 9 and 10 are closed. In this case, the inverting amplifier 7 is disconnected from the source of the signal and is in the correction mode of its own zero drift by storing it in the second memory element 8 dp of compensation in the subsequent clock cycle. The voltage memorized in the first cycle is applied to the non-inverting input of the op-amp 1 and compensates for the drift zero of the last.

Both correction cycles are simultaneously operational. Pulse frequency of the reference generator I1 f controlling the operation of the tripping 3 and 4

and the locking keys 9 and 10 are determined by the quality of the circuit elements.

Thus, in the proposed device, the drift zero is significantly reduced.

Claims (2)

1. The patent of Germany No. 2.506.162, cl. H 03 F 1/30, 1976. 2. Volgin L.I. Linear electric transducers for measuring instruments and systems. M., Soviet Radio, 1971, p. 119, fig. 2.576 (prototype).