SU731309A1 - Photographic registering device - Google Patents

Description

a sator 3 and a resistor 4 in the open circuit; 1X10y feedback. The output of the photo iris device 1 and the outputs of the amplifying cascades; 1 and 2 are connected to the signal inputs of the corresponding nick detectors 5, connected via an analogue circuit "IL14" to the input of the converter 7 "and a terminal code. The outputs of the amplifier stages 2 are also connected to the inputs of the room 8 8, the second inputs of which are connected to a low voltage supply 9. The outputs of the comparators 8 are connected via a register 10 to the inputs of the decoder I, the outputs of which are connected to the encoder 12 and to the control inputs of the peak detectors 5. In addition, the output of the comparator 8, which is connected with the last-stage cascade of the amplifier 2, is connected via a differentiating circuit 13 to the inputs of the shaper 14 nmnzlsov, the output of each of which is connected to the input of the corresponding key 15, to the shunt present a coupling capacitor 3, and to the input key 16, the resistor 4 schuntnruyuschego Exalt negative feedback amplifier stage 2.

The device works as follows.

The photodetector 1 converts the pulses of the radiant flux into electrical signals, which are injected into the input-stage amplifier 2. In this case, the amplitudes of the stages of the amplifier 2 start from the last. Let the signal be of such magnitude that the cascades, 2 with ordinal numbers from 1st to (k-1) -th are located. in the unsaturated state, and cascades 2 with numbers from the kth to the lth are saturated. In this case, pulse comparators 8, corresponding to saturated cascades, will work. The threshold voltage, which is applied to the second inputs of the comparators 8, is set slightly below the upper limit of the dynamic range of each amplifier stage 2. Then, in register 10, a code is set to the order of the input signal value, the higher (from n to k) bits of which contain and the minor ones (from 1 to (k-1) -notes. The indicated code is converted by decoder 11 into (- | -1) - the digit code "1 out of l, whose unit sequence number among the zeros corresponds to the number of the last unsaturated cascade 2, in this case (k-1) -th.

The signal output from the output of the specified stage 5 is stored in the corresponding peak detector 2 selected by the code "1 of l.

At the output of this peak detector 5 there is a quasi-constant injection, expressing the mantissa of the signal in analog form, and at the output of the other peak detectors 5 there are zero levels. Analog value of mantissa, passed through

The "OR 6," circuit is converted into a digital binary code by the converter 7 "and the source code. The storage time of amnlntuda voltage in peak detector 5 should

be no less than the time to convert the voltage into a code. The code "ior" 1 of l is also converted into a binary code by the identifier 12. At the output of the device there is information about the size of the received signal

In digital form, which is convenient for its yes. most processing. In addition, since the amplitude characteristic is linear in the proposed device in any part of the dynamic range, the accuracy of measuring pulse amplitudes over the entire dynamic range is the same.

When large input signals cause saturation of one or several amplifying stages 2, the comparator 8 is triggered. Differentiating value 13 but ending the pulse of the comparator 8 starts the drivers 14 imulses. The formers 14 simultaneously open the keys 15 and 16. The keys 15 at that disintegrate the fast discharge of the separation capacitors 3, and the keys 16 reduce the transmission coefficients of each of the amplifier stages 2 to one and thereby exclude the possibility of overloading

the amplifier during the switching of the keys 15. As the duration of the pulses at the outputs of the formers 14 is not the same and increases with the sequence number of the driver 14, the keys 15 and 16 return to the initial state non-simultaneously, and the amplification of the cascades 2 is restored consequently, starting from the first. Due to this, suppress the interference arising on the fronts of the control nanometer pulses

keys 15 and 16. For idle noise on the switching fronts, the control pulses have a trapezoidal shape with a reduced voltage drop rate.

Thanks to the introduction of the nth comparator 8, the differentiating circuit 13, the formers of impulses 14 and the keys 5 and 16, the sensitivity of the amplifier is quickly restored. The recovery time is a fixed, previously known and many times smaller recovery time, which occurs by natural discharge of the separation capacitors 3. This allows you to completely eliminate measurement errors aglnlitudy caused by transients after exposure, when the repetition period of the input signals is commensurate with recovery time. The proposed photoregulator provides a piecewise linear amplitude characteristic of the photo recorder with the same absolute accuracy from the measured level of the radiant flux in the entire amplitude

dynamic range.

Claims (2)

Invention Formula A photoregstrator containing a photodetector, to the output of which connect the input of an L-stage amplifier, each stage of which contains an input capacitor and a resistor in the negative feedback circuit, and the output of the photon-receiving device and the outputs of the amplifier stages are connected to the signal inputs of the corresponding (l + 1 a) peak detectors connected via an analog circuit "OR to an input of a converter" voltage-code, characterized in that, in order to reproduce accuracy, a regis is added to it tp, decyfrater, differentiating circuit, n pulse shapers, 2p keys, source of threshold voltage and l comparators, the first inputs of which are connected to the outputs of the amplifier stages, the second - to the source of the threshold input, and the outputs through the register - to the descrambler connected by their outputs to the tuner and the control inputs of the peak detectors, the output of the last comparator through the differentiating circuit is also connected to the inputs of the pulse formers connected to the n-stage amplifier, so that the output Each driver is connected to the input of the key, bypassing the coupling capacitor, and to the input of the key, bypassing the resistor in the negative feedback circuit of the amplifier cascade. Information sources, taken into account during the examination 1. V. Volkov. Functional amplifiers with a large dynamic range. M., “Soviet Radio, 1976, p. 37. 2. Maksimov M. V. Protection from iomekh. M., “Soviet Radio, 1976, p. 193 (prototype).