SU935812A1 - Digital meter of infra-low frequency period average duration - Google Patents

Description

Pa drawing - the block diagram of the digital meter of the periods of infra-low frequency is shown functional.

The device contains a control unit 1, a reference frequency generator 2, the output of which is connected to a controlled frequency divider 3, the control input of which is connected to the first output of control unit 1, elements 4 and 5, the first inputs of which are connected to the output of the frequency divider 3, and the second inputs - with the second and third outputs of control unit 1, counters 6 and 7 of pulses connected to each other by means of memory block 8, the OR element 9, the first input of which is connected to the overflow of counter 7, the second input to the output of the AND 5 element, and the output to the counting at the input of the counter 7, the output of the element 4 and 4 is connected to the counting input of the counter 6, the glowing adder 10, the control input of which is connected to the fourth output of the control unit 1, and the discharge inputs are connected to the discharge outputs of the counter 7, the fifth and sixth the outputs of the control unit 1 are connected respectively to the control inputs of the pulse counter 6 and the memory block 8 “I

Before the beginning of the measurement, the control unit 1 is given the number of subsequent periods of infra-low frequency g whose average value is to be measured, and the time T, calculated from the condition where WA is the estimated minimum value of the measured period. The control unit 1 sets in divider 3 a predetermined division factor

The device works as follows.

With the arrival of the first measured period, block 1 opens element I 5 and counter7. 7 begins to count the number of pulses arriving at its input from divider 3 through elements 5 and 9. After time Tu, after the beginning of the first and each subsequent period, block 1 opens the element And 4, thereby connecting to the input of the counter, the output of the divider is 3 frequencies, and the counter 6 begins to count the incoming; 1ydie to its input and 1L1 pulses.

After the end of the measured period, the blob 1. closes the AND 4 element, rewrites the contents of the counter 6 into the memory block B, and sets the counter b to the initial state.

After the end of the first n periods, the average value of the measured periods Npp.yi is found in the counter 7, and the variable components of the measured periods NI -1 are recorded in block 8 of the memory. m .f

N

t +,

Tu

cf.

and

Kl P

Ki

P

f

to

- i. V t

 p, vi;

; i)

1 (.-- gy

where T is the duration of the i-th period;

 - frequency of oscillator 2. After the end of the n-th period, block 1 closes element 5 and rewrites the contents of counter 7 into cyiv; MaTop 10 k reads from block 8

5 memories in counter 7 is the numerical value of the variable component of the first period N in the return code. Through time T after the beginning of the (n + 1) -th and each subsequent period, block 1

Q opens the elements of And 4 and 5, and the counters 6 and 7 begin to count the pulses arriving at their inputs, and the counter 7 summarizes the number of counted pulses with a reverse code

with the variable components of the 1st period, thereby determining the difference between the (n + 1) -th and 1st periods.

If counter 7 overflows, the transfer unit from its most significant bit through the element OR 9 goes to

 This is a counting input, which prevents the loss of a unit when summing.

If T,., - is both greater and equal, the difference between periods will be represented in the reverse code.

Thus, in counter 7, the numerical value of the difference is represented in a code suitable for direct input to the accumulating adder,.

After the end of the chamber period, the UO commands of block 1 are closed, elements 4 and 5j are closed, and the code from counter 7 enters accumulating adder Y. The described sequence of operations is repeated for each subsequent n: o. Code in the adder 10 after the yeni (n + 1) -th period defined. gsk ratio 1 l

NCP (...., ,, - ™ (1y, -T „) +

, if

+. (t, ...

.li

(2)

P . ; And P -.

Accordingly, after measuring the (n + j) -ro period

.fc lt

N,

eleven ,

S

P1

ii j

Thus, in the adder 10, there is a constant numerical value of the average duration in advance of a predetermined number of the last periods of the infra-low frequency, which is updated after the end of each slot .yy / period of the measured period.

This is the possibility of adjusting the 5 result of the Measurement of the expiration

Claims (1)

Claim A digital meter of medium duration of periods of infralow frequency, containing a reference frequency generator with a controlled frequency divider at the output, first and second pulse counters connected through a memory unit, a control unit and logic elements, is distinguished by the fact that, in order to increase dynamic accuracy by measuring the average duration for a given number of recent periods of the infrared frequency, an accumulating adder is introduced into it, the bit inputs of which are connected to the bit outputs of the second pulse counter owls, 5 and the overflow output of the second counter is connected through the element OR to the counting input of the second counter, and the output of the controlled frequency divider is connected through the corresponding elements AND to the counting input of the first pulse counter and to the second input of the OR element, the control inputs of the AND elements, the first counter, the memory block accumulating 15 adders and the frequency divider are connected to corresponding outputs of the control unit, the input of which is connected to the signal bus of the measured infra-low frequency. 20 I