SU1179329A1 - Device for taking logarithm - Google Patents

Abstract

A device for logarithmization, containing a mantissa counter, a characteristic counter, a counter, differing in that, in order to improve the accuracy of the logarithm, an encoder, a programmable counter and a multiplexer are entered into it, and the device input is connected to the information input of a programmable counter, the output of which is connected; . To the first and second information inputs of the multiplexer and to the counting input of the counter, the first, second, third, fourth and fifth outputs of which are connected respectively to the third, fourth, fifth, sixth and seventh information inputs of the multiplexer, the output of which is connected to the input of the counter of the mantissa whose transfer output is connected to the input of a characteristic counter, the output of which is connected to the control input of a multiplexer and is the output of a characteristic of the device, the outputs of the higher bits of the counter mantissa dineny the inputs (A coder, whose output is connected to a control input of the programmable counter, the counter outputs are mantissas of the mantissa output device ..

Description

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S. 1 1 The invention relates to calculating devices and is intended, in particular, for use in radiation measuring apparatus recording devices. The purpose of the invention is to improve the logarithm accuracy. FIG. 1 is a functional block diagram of the device for logarithmization; in fig. 2 - schematic diagram of the encoder; in fig. approximation characteristic of the device, realizable with the use of this encoder. The device for logarithmization contains counter 1 programmable counter 2, multiplexer 3, counter 4 mantissa counter 5 characteristics and encoder 6. Encoder 6 contains the decoder 4 input element 1 SP 8, input 3 OR 9 and element 10. The device works as follows. Before the next measurement, all device counters are set to zero. The zero value of the code at the output of counter 5 of the characteristics corresponds to the closure of the first channel of the multiplexer; with this, the input pulses go through the programmable counter 2 and the multiplexer to the input of counter 4 of the mantissa. The average value of the recalculation coefficient of the programmable counter 2 is chosen equal to the base of the logarithmization, for example 2. In this case, to change the state of the characteristic counter by one, K K input impuls is required, where Kf is the average value of the recalculation coefficient of the programmable counter; K .. - coefficient overlap L.. counter.mantissy. For example, when using a two-digit decimal counter as counter 4 of the mantissa, a change in the state of counter 5 of the characteristic from 0 to 1 occurs when two hundred pulses enter the device input. Change the code on the output counts. 5 characteristics leads to the inclusion of the second channel of multiplexer 3. 292 Since this channel is closed with the first channel, counter 5 of the characteristic from 1 to 2 will switch when another two hundred pulses arrive at the device input. Subsequently, the input of counter 4 of the mantissa is sequentially connected to the outputs of binary counter 1, which doubles the number of input pulses for each subsequent unit of characteristic and provides a rough approximation of the logarithm function with values of the characteristic of the logarithm. large units. A more accurate approximation is carried out by adjusting the recalculation coefficient of the programmable counter 2. This adjustment is carried out in accordance with the approximation broken line shown in FIG. 3. The sections of the approximating broken line correspond to the conversion factors of the programmable counter 2 64 „64 t /.: I7-t / - 40 2 31 a The average value of the conversion factor of the programmable counter 2 with selected K is Kp log) Kn + () K + 64 „.44 + (& log) Kn 0.4 + 0.3 1.998, where (u, log) is the logarithm increment for the i-th approximation area. Thus, the approximation error on the basis of the logarithm at the selected approximation coefficients does not exceed 0.1%. To implement these: conversion factors, a code is used that arrives at the control inputs of programmable counter 2 from the encoder 6. Suppose that the programmable counter 2 is controlled by -speed binary code. Then, in order to realize the conversion factors corresponding to the approximation shown in Fig. 3 to 3, the encoder 6 must function in accordance with the data presented in the table. After simple transformations 4 3 P P X, 1 with p 0-3; X ,, X ,. X, To determine p, a decoder 7 is used that converts a binary-decimal code to a positional one connected by inputs to the high-order outputs of the counter 4 mantiss DP for further conversion using two logical elements OR 8 and 9 and an element NOT 10. Presented table of the function of the encoder 6 is only a variation of the processing algorithm used in the device. The encoder 6 can be made J3 in the form of a persistent storage device using a much larger number of input and output buses and allowing a significant increase in the logarithm accuracy. Thus, the proposed device allows not only to increase the logarithm accuracy by an order of magnitude, but also to directly log the number of pulses received at its input without any intermediate operations; logarithm over a base other than two, and also obtain a sequence of pulses, the frequency of which is varied in time according to a logarithmic law. The output of the device in this case is the output. Multiplexer 3.

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Claims (1)

A LOGARITHMATION DEVICE containing a mantissa counter, a characteristic counter, a counter, characterized in that, in order to increase the accuracy of the logarithm, an encoder, a programmable counter and a multiplexer are introduced into it, and the device input is connected to the information input of the programmable counter, the output of which is connected to the counter input characteristics, the output of which is connected to the control input of the multiplexer and is the output of the characteristics of the device, the high-order outputs of the mantissa counter are connected to the input and an encoder, whose output is connected to a control input of the programmable counter, the counter outputs are the outputs of the mantissas of the mantissa 'device. . Fie. 1 m s © co s ©>