SU868789A1 - Multichannel statistic analyser - Google Patents

Description

The invention relates to apparatus for the statistical analysis of random processes, in particular, to the measurement of probability density functions of events, the parameters of which can be represented as electrical impulses of corresponding amplitudes, and can be used in nuclear physics, medicine, space research, geology, etc. for both one-dimensional and multidimensional analysis. A multichannel analyzer is known that contains an analog-to-digital converter, an address register whose input is connected to the output of a code bazovatel, microprogrammed control device (SMS), the start input of which is connected to the inverter output of the converter, 4 microsignal outputs to the recording Record connected to the unlock input of the converter, random access memory, the address input of which is connected to the output of the address register, read start input is connected to the output firmware signal Readout of control device 1 The accuracy of a multichannel analyzer is characterized by values. tegral and differential linearity. Integral linearity characterizes the accuracy of the location of the centers of the channels with respect to the linear law or, in other words, characterizes the proportionality between the channel numbers and the corresponding input amplitudes, and the differential linearity is the degree of constant channel widths measured with respect to the average channel width input analog-to-digital converter (ADC). Both integral and differential linearity of the analyzer are indicative of the accuracy of the ADC unit, since it only determines the number of channels for classifying events. Differential nonlinearity (as opposed to integral) appears only during statistical analysis, i.e. after accumulating enough measurements. It should be emphasized that, although the differential nonlinearity in its physical nature is the error of the ADC, this error is revealed only by statistical sorting of measurement results using digital data storage devices or similar instruments and data acquisition systems in which there is a large enough sorting the number of measurement results. In this sense, the differential nonlinearity is specific to a multichannel analyzer as a whole. . Thus, the disadvantage of such a multichannel statistical analyzer is differential nonlinearity. The closest to the present invention is a multichannel statistical, an encoder containing a pulse expander, a three-input comparison circuit (CC), the first input of which is connected to the output of the pulse extender, a digital-analog converter (D / A converter), the output of which is connected to the second output of the CC, a device generating the code whose control code input is connected to output C, the code output is connected to the input of the D / A converter, the address register (PA), the input of which is connected to the output of the firmware control code generator -keeping, whose output is connected to the input entry unlock code forming apparatus, a random access memory (RAM) r21. The known analyzer provides measurement of amplitude spectra with a differential nonlinearity of 1%. However, in a number of cases, for example, when measuring spectra with relatively narrow and closely spaced peaks, less differential nonlinearities are desirable. In addition, the occurrence of loss of information due to holes on the measuring scale of the analyzer, which are generally undesirable, can be fundamentally unacceptable in a number of measurements, for example, when measuring narrowly narrow spectra. Thus, the main disadvantages of the known statistical analyzer are information losses from the discontinuity of the measuring scale and a relatively large differential for nonlinearity. The purpose of the invention is to improve accuracy by eliminating the loss of information from the discontinuity of the measuring scale and improving differential linearity. The goal is achieved by the fact that the multichannel statistical analyzer, containing the first peak detector, whose information input is the input of the analyzer, and the output is connected to the first input of the comparison circuit, the second input of which is connected to the output of the digital-to-analog converter, the bit inputs of which are connected to the bit outputs ds1M of the code forming unit, the control input of which is connected to the output of the comparison circuit, and the output end of the conversion is connected to the gate input of the address register directly o, and through the first delay element to the read input of the random access memory, the information input and output of which are connected respectively to the output and the input of the register of the number register, the main input of the random access memory is connected to the output of the address register, whose information input is connected to the bit outputs the code generation unit, a voltage converter is entered into the code, a second peak detector, a second delay element, and a differential amplifier, whose input is connected to the digital output and the output is connected to the information input of the second peak detector, the output of which is connected to the information input of the voltage converter into a code, the information output of which is connected to the information input of the number register, and the output end of the conversion is connected to the input of the number register register directly, and the delay element is connected to the input of the random access memory, to the reset input of the first peak detector and to the input of the blocking block of the code generation; the reset input of the second peak detector and the blocking input of the voltage converter in the code are combined and connected to the output end of the converter, code generation unit. The drawing shows the block diagram of the proposed multi-channel statistical analyzer. The analyzer contains a random access memory (RAM) 1, address register 2, register 3 numbers, peak detector 4, comparison circuit 5, digital-to-analog converter 6, code generation unit 7, differential amplifier B, second peak detector 9, voltage converter 10 in code , the first delay element 11, the second delay element 12, the output 13, the conversion end, the blocking input 14. The analyzer works as follows. The input pulse, the input to the analyzer input, is recorded at its maximum by a detector of 4 input pulses. The fixed amplitude voltage of the pulse arrives at the first input of the comparison circuit 5, the second input of which is affected by the output voltage of the converter 6. The output signal of the comparison circuit 5, which is a logical signal of the sign of the difference of the voltage levels, acting on it the first and second

inputs, enters the control input of the block 7 code block. The code formation block 7 selects a code, the analogue of which is the output of a digital-to-analog converter, is accurate to the channel width and is equal to the measured voltage. On completion of the measurement process, unit 7 signals by issuing (output 13) a signal to the end of the conversion, under the influence of which the channel number code is recorded at the gate 2 input of the register 2 address, which comes at the time from the output of block 7 to the register 2 input. The signal end of the conversion is also input resetting the second peak detector 9 pulses and to the blocking input of the converter 10, driving them to the ready state for fixing and measuring the amplitude of the internal pulse of the circuit. In addition, the same signal from the output of the output of block 7 7 is fed to the first delay element 11, and from its output goes to the read start input of the random access memory 1, causing the read from RAM 1 to register 3, which is in the address (channel), the code of which was entered before it in the register 2 addresses. Further operations related to the input event, in the proposed analyzer, are a fundamental difference.

After a period of time sufficient to rewrite the channel number from block 7 to address register 2 and bring the second peak detector 9 and converter 10 into readiness, block 7 increases the code at its output by one. Accordingly, the voltage at the output of converter 6 is changed by the width of the channel into which the measured amplitude has fallen. This stepwise (stepwise) voltage change at the output of the digital-analog converter b arrives at the input of a differentiating amplifier 8, at the output of which a pulse occurs whose amplitude is proportional to the jump at the output of converter 6, i.e. channel width. This pulse is detected in amplitude by the second detector 9, from the output of which the voltage is fed to the input of the voltage converter 10 to the code (inverse; proportional code). Upon availability of this code, the output of the conversion end of the converter 10 results in a signal of the conversion end arriving at the input of the addition of the register register 3 numbers. As a result, a code inversely proportional to the width of the channel to which the event counts is added to the contents of register 3. Further, after a delay time determined by the second delay element 12, the enlarged contents of register 3 return to RAM 1 under the influence of

. The output of the element 12 to the write trigger input RAM 1, and the same delayed pulse, the peak detector 4 and the code generation unit 7 are reset (unlocked). After this, the dialyzer is ready to process the next pulse. An increase in accuracy due to the elimination of event losses and a decrease in the differential nonlinearity in the proposed analyzer is achieved by taking into account all events whose codes are defined (i.e., pteri are eliminated), moreover, events are not recorded

5 in the form of units added to the channels as fractional numbers, taking into account the relative probability of an event entering the given channel. Indeed, the wider the channel, the more often

0 events get into it, however, since each of them is represented by a value inversely proportional to the channel width, the effect of the unevenness of the channel widths on the appearance of the spectrum is eliminated — the spectrum becomes

5 differential linear.

Claims (2)

1. Tsaregorodtsev M.N. Nuclear electronics. M., 1968, part 2, p. 1313135. 2. Franz K "Schuir I., NAC-NRC Publications, 1184, Washington, 1964, 172.