SU1695331A2 - Function generator - Google Patents

Description

one

(61) 1283806

(21) 4746421/24

(22) 10/02/89

(46) 11/30/91. Bul №44

(72) E.V. Borisov

(53) 681.3 (088.8)

(56) USSR author's certificate

No. 1283806, cl. G 06 G 7/26, G 06 F

1985.

(54) FUNCTION GENERATOR (57) The invention relates to specialized means of computing, can be used to determine the membership function of Mu (y) functional transformation y

1/02,

Lizi those for awn y

f (x) is a fuzzy variable X {x, MX (x)}, where MX (x) is the membership function of the element x to the set X. The purpose of the invention is to enhance the functionality by ensuring the use of fuzzy sets with membership functions of a discontinuous type. The pulses of the GTI 1 using the sawtooth voltage generator 6 and controlled by the analyzer 13 of the argument value of the switch 11 at the output of the element OR 12 form a symmetric function of belonging to a discontinuous type, whose samples are digitally formed through the block 8 of the elements And 4. 2 Il.

g

fe

14

About Yu (L

with so

Fm.1

Yu

The invention relates to specialized means of computing, can be used to determine the membership function y (y) - functional transformation y f (x) fuzzy variable

X {x, Mx (x)},

where MX (x) is the function of belonging of the element x to the set X, and is an improvement of the known device according to the author. St. No. 1283806.

The purpose of the invention is to expand the functionality by ensuring the use of fuzzy sets with membership functions of a discontinuous type.

FIG. 1 is an electrical block diagram of a function generator; in fig. 2 - auxiliary graphics - type of membership function.

The function generator (FIG. 1) contains a clock pulse generator 1, a counter 2, a digital-to-analog converter (DAC) 3, a comparator 4, an exponential signal generator 5, a sawtooth voltage generator b, an analog-to-digital converter (ADC) 7, and element 8 , the first and second delay elements 9 and 10, the switch 11, the OR element 12, the argument value analyzer 13, as well as the third and fourth delay elements 14 and 15.

The output of the generator 1 through a serially connected counter 2, a DAC 3, a comparator 4 and the second delay element 10 is connected to the input of the generator 5, through the first delay element 9 to another input of the generator 1, and through the serially connected generator 6, switch 11. OR 12 and ADC 7 - with the input of block 8, the output of counter 2 through the analyzer 13 is connected to the control input of the switch 11, the outputs of which through the third and fourth delay elements 14 and 15 are connected to the second and third inputs of the OR 12 element, respectively.

The analyzer 13 is in the form of a ROM operating in read mode. The remaining blocks are standard computing blocks.

The function generator works as follows.

The membership function of the variable x is defined as a function of approximate equality, which is formed as a discontinuous triangle (Fig. 2) by the sawtooth generator 6 and the elements 11-15. The functional transformation of the variable x is given as an exponential transformation y-ex.

which necessitates the implementation of the generator 5 in the form of an exponential signal generator. At the starting input of the generator 5 is included a delay element (not shown).

Operation begins by turning on the clock pulse generator 1. Counter 2 counts the number of pulses. Each of the states of counter 2 corresponds to the current value of y. The determination of Mu (y) is made for each of these values in the intervals between the pulses of the generator 1 from y 1 to y memex. which is calculated counter 2.

5The state of counter 2 is converted to

the analog form of the DAC 3 and is fed to the input of the comparator 4. At this time, generator 5 begins to generate an exponential signal, and at some point in time when the signal from the output of generator 5 exceeds the signal from the output of the DAC 3, at the output of comparator 4, which enters the inputs of the block 3 elements I. At the same time, the pulses of the generator 1

5 clock pulses are applied to the input of the sawtooth voltage generator 6. At the input of the generator b, a delay element (not shown) is included for the transient time in elements 2 and 3. For each of

0 pulses, the generator 6 generates one saw-tooth pulse, which with the help of elements 11-15 is converted to the form shown in FIG. 2. This happens as follows.

five

As long as the contents of counter 2, equal to x (by x, is meant the periodic function of time with a period equal to the period of the pulse generator 1, less

0 XL analyzer 13 generates a code in accordance with which the input of the switch 11 is connected to the input of the element OR 12 directly. When xi x x 2, the input of switch 11 is switched to the input of element 14

5 delays, the delay of the signal in which is carried out for a time interval proportional to the difference x - XL If ha x xs, the delay element 15 is connected, and at x xz the input of the switch again connects

0 with the input of the element OR 12. Thus, at the output of the element OR 12, a signal is generated, the shape of which corresponds to the form of the initial membership function MX (x) (Fig. 2). This signal is converted to

5 digital form in the ADC 7, therefore, when a polling pulse is applied to the inputs of the block 8 elements, the output of the function generator receives the value of the membership function Mu (y) in digital form for the current values of y.

In addition, the polling pulse from the output of the comparator 4 resets the generator 5 to the initial state.

The described processes are repeated for each of the pulses from the output of generator 1. The function generator is stopped by stopping generator 1 by a reset pulse from the overflow output of counter 2 to the stopping input of generator 1 through delay element 9.

Claims (1)

Invention Formula Function generator auth. St. No. 1283806, characterized in that, in order to expand functional functions capabilities by ensuring the use of fuzzy sets with membership functions of a discontinuous type, a switch, an OR element, a third and fourth delay elements, and an argument value analyzer whose input is connected to the counter output, and the output connected to the control input of the switch the output of the sawtooth generator is connected via a switch directly, as well as through the third and fourth delay elements, to the first, second and third inputs of the OR element, the output of which is connected to the analog input o digital converter.