SU995039A1 - Automatic gain control circuit - Google Patents

Description

(54) AUTOMATIC ADJUSTMENT DEVICE

GAINS

one

The invention relates to radio engineering and may, for example, be used in a radar receiver.

A device for automatic gain control is known, which has an accelerated-gain control process by introducing an analog-to-digital converter 111.

 However, this device has a number of disadvantages, the most significant of which are the continuous adjustment of the signal from cycle to cycle and sequential output of the output signal.

The closest to the invention in its technical essence is an automatic gain control device g containing N series-connected amplifiers, the output of each of which is connected to an output adder via a corresponding key, as well as a programmer, and the control inputs of the keys are connected to the corresponding outputs of the deshifter.

The device performs parallel removal of the output signal. At the same time, when switching keys, the leading edge of the signal of the previous section of the long-range one key begins to decrease, and the leading edge of the signal of the subsequent section of the range with a different input signal intensity begins to increase, and the total voltage of the sypnal at the output of the common output stage remains constant. This allows 1 hour to talk about instantaneous switching of the signal voltage and the absence of loss 2.

A disadvantage of the known device is the fact that the initial installation of the required gain takes several cycles of work to sequentially poll the keys.

The purpose of the invention is to increase the speed of regulation.

The goal is achieved by the fact that the automatic gain control device containing N consecutively connected amplifiers, the output of each of which is connected via a corresponding key to the output adder, as well as a programmer, with the control inputs of the keys connected to the corresponding outputs of the decoder, to the input of the first amplifier. An input detector is connected, and between its output and the decoder inputs are M channels, each of which is made as a series-connected comparison element with a threshold, a digital integrator and a storage element, while the control inputs of the digital integrators and storage elements are connected to the corresponding outputs of the programmer. FIG. 1 shows a structural electrical circuit of the proposed device; in fig. 2 is a structural electrical circuit of one channel. The automatic gain control device contains t-connected amplifiers 1, an output adder 2, a detector 3, channel 4 channels, each of which contains a comparison element 5 with a threshold, a digital integrator 6 and a hall - a tailing element 7, a decoder 8, a programmer 9, N keys 10 The device operates as follows. In the absence or at the input of a device of weak signals, in which the signal at the output of the output adder 2 does not reach the established upper limit of the linear portion of the amplitude characteristic, the signal at the output of the detector 3 does not exceed the response threshold of the comparison element 5 included in the first channel 4. In this In this case, the signal from the output of the decoder 8 opens the S and key 10, while all other keys are closed. In this case, the device sprays with maximum gain. When a signal is input to the device. Since the signal voltage in the input adder 2 reaches the weights of the linear part of the output amplitude response 1W, the voltage at the output of the detector 3 exceeds the response threshold of the comparison element 5 of the first channel 4, and the comparison element generates an overrun signal whose duration is proportional to the duration of the signal exceeding the threshold srabatan. This signal is then fed to the input of the digital integrator 6, where the counting of the clock pulses that have passed to the counter during the duration of the exceeding signal is performed, and then the pulse of the result is expanded to the closest range mark. From the output of the digital integrator 6, the extended pulse is fed to the input of the jamming element 7, in which the azimuth and range method is recorded on a simultaneous command. as an example, we suggest that from the programmer 9, 10 µm distance marks and 5 azimuth marks are supplied. Then the change of the recording information in the resomination device occurs at the end of each 1O km of the distant section and after every 5 ° rotation in azimuth, the Signal) from the output of the memory of the 1 element 7 enters the decoder 8, which closes N - and key 10 and opens the N -1 key 10. All other keys are locked. Thus, the signal at the output of the device comes only from the next-to-last amplifier and the device gain is decreased by Kj i, so that the output signals from the output adder 2 do not exceed the set value. I If the signal at the input of the device continues to increase, the voltage at the output of the detector 3 and the output adder 2 increases accordingly. When the voltage of the signal in the code adder 2 again reaches the nonlinear part of its output amplitude characteristic, the voltage of the signal at the output of the detector 3 reaches the response threshold in the second channel 4. This channel, together with the first channel and the decoder 8, locks the control signal, which opens only the key that provides a reduction in the device gain in To ni- I P dG Kuu, - the gain factor of the last but one. His amplifier is from a group of N series-connected amplifiers. And finally, when the detector output signal exceeds 3 thresholds of the Hth channel 4, all N channels 4 transmit H signals to the decoder 8, which, in turn, generates a signal that opens the first key 10 and shakes all the other keys In this case, the device has a minimum gain (yn) -th amplifier, t, e, of the first amplifier 1,. Thus, when a powerful signal arrives at the device input, inputting all serially connected amplifiers (except the first amplifier 1) to saturation, the output signal of the detector 3 simultaneously exceeds all IH thresholds and the decoder 8 disconnects all amplifiers that are in saturation from the UHC adapter 2 and connects the first amplifier 1.

The determination of the required gain occurs in the first cycle of operation of the devices 1. In the second cycle of operation, this gain is established and maintained further unchanged in all of the selected azimuth far-distance.

The advantage of the proposed device is that when a powerful input signal is applied, the output signal of the signal for setting the required gain. occurs in one cycle of operation, while setting the required amplification per cycle takes I times more and when the power of the input signal varies from cycle to cycle, the gain setting is undefined

The application of the proposed device allows to increase the speed of regulation due to the establishment of the necessary

transmission coefficient of the device in the first cycle of operation.

Claims (1)

1. US Patent 3,944,942, cl. USP-86, 1976.2. US patent number 3603972, cl. 340-347, 1971 (prototype). R fft / JTff l