SU705365A1 - Digital device for measuring on-off time ratio for square pulses - Google Patents

Description

(54) DIGITAL RING EMISSION METER

PULSES

- f f f The invention relates to the field of electrical measuring equipment and can be used to measure the wellness of direct molar pulses. With a count of results directly in units of a duty cycle in a wide range of pulse durations of the sequence under study. A known electron-counting frequency meter f contains a frequency divider selector, a high-frequency driver, a block of counting decades, a time stamp generator 1. However, this clock has a low measurement accuracy during the duration of the pulses under study. Also known is a digital meter for the duty cycle of rectangular pulses with a sample of the result directly in units of the duty cycle, containing the reference frequency generator, the first and second keys, the Ishluso trigger frequency divider, and the pulse counter 21. However, this meter cannot provide a wide range of pulse durations sufficiently high measurement accuracy, as in order to ensure high measurement accuracy, it is necessary that the / number of bursts of pulses received during the measurement tim input to the frequency divider, is sufficiently large. The aim of the invention is to improve the measurement accuracy. To do this, a digital key for measuring the duty cycle of rectangular pulses, containing a reference frequency generator, a pulse counter and a first key serially connected in a ring, a frequency divider, a trigger and a second key, the output of which is connected to the input of a pulse counter, is entered with a frequency divider with a control factor; dividing unit and a unit for measuring the duration of the pulses, in which connected to the second input of the first key, the first output is connected to the second input of the trigger, and Costal outputs connected to the inputs of the frequency divider with a controlled division factor, the circuit that the output of the reference frequency generator is connected to the second input of the second key. The structural electrical circuit of the digital meter is shown in the drawing.,

The device contains a generator of ethon frequency 1, a divider 2 frequencies with a controlled division factor, a switch 3, a pulse counter 4, a switch 5, a frequency divider b, a trigger 7, a pulse duration measuring unit 8 consisting of a clock frequency pulse filling element 9, preliminary counter 10 and output counter 11. The device operates as follows, -, time.

The start signal starts the first measurement step, in which the element 9 performs filling the pulse frequency of the test sequence with a clock frequency. As a result, 5 of this process, on a preliminary counter of 10 pst per unit pulse packet, i the number of pulses m in this packet will be equal to. , -.

m.

Pre-count volume

10 Must be P BUNO; Dov, and is selected depending on

the specified minimum duration of the studied pulses, y, 1n. 25 Overflow of this counter Yu DbIt will occur at the next. In other words, the pulses under study tr have the values tm-ih in, i.e. P Eod2 (t; 1G) + 1. 30

For each overflow of the conventional counter 10, an impulse arrives at the output counter 11, and by the end of the First measurement stage, at the output 35, the counter will receive k pulses. Moreover, k will be equal to the integer part of the ratio of the duration of the pulses under study; To the specified minimum value; The duration of the studied pulses 40 tviin, that is,

 - ok entire

:; : Cttlin. :.; ..:.:. Thus, by the end; peryogb. measurement stages on the output counter,

11 a binary code k / equal to the integer part of the relation, will be written. The spacing To the external counter 11 and

 The frequency divider 2 should not be the dynamic range of the durations of the investigated SPEs. SOV. X .-

 . WITH

, - the specified maximum pulse duration of the probing pulses is 55 Otherwise, counter 11 may overflow, which will distort the measurement result - -V ------ - - - - - -. .. -, .. / ....,., -, .-, .-

Since the trigger outputs of the gg 11 counter are connected to the control buses of the controlled frequency divider 2, the division ratio of the controlled divider during the measurement of the duty cycle of the drill is equal to k ,. x65

At the end of the first measurement step, the impulse 7 arrives at the output of the element 9, and the second stage of the direct measurement of the duty cycle Q begins. The trigger 7 opens the key 3 at its output pulses with a repetition frequency fo / 1 appear. These pulses are fed to the pulse counter 4 and to the input of the key 5. The rectangular pulses under study are fed to the control input of the key 5. At the output of key 5, a burst of pulses with a duration f and a repetition period T occurs. The number of pulses in each burst will be equal to

- p ff IT V

The pulses from the output of the switch 5 arrive through a divider b with a division factor of N per trigger 7. At the exit of the divider b, a pulse arises after being received — on its entrance N pulses. The trigger pulse 7 returns to the open state by means of the pulse, the key 3 is closed, the pulses from the output of the controlled frequency divider 2 stop flowing to counter 4 and the key, 5, and the measurement ends. The number of pulses. Received at counter 4 during the time of the rhenium, will be equal to

-V- 4v, - - J-O -t.

about-

The time to measure the duty cycle t nodes is equal to the time during which the key 3 is opened. In turn, this time is equal to the time interval during which N pulses are applied to the input of the divider b. In this way

41 JL t k-kl. . -HW n ± 0 Therefore, the number of pulses N ,,, Received on counter 4 during the measurement time, will be - - So T

NO - r-fcv, that is, the duty cycle is equal to T Wt

  H

Q

By the end of the second stage of measurements 15, the counter 11 will store information about the duration of the pulses under study T, and in the counter 4, information will be stored. qi on the duty cycle of the investigated. sequence Q ..

Claims (2)

Thus, due to the automatic switching by means of a controlled frequency divider of the reference oscillator in accordance with the duration of the pulses under study, the number of packs of owls arriving at. the divider b input can vary in the whole range of durations of the pulses under study not more than two times, i.e. with an accuracy to the discreteness of setting the conversion factor of the controlled frequency divider 2. Moreover, the duration range can be arbitrarily wide and only on the counter 11 and the range of the conversion factor of the controlled frequency divider 2. The maximum instrumental error in measuring the duty cycle in the entire range of the durations of the pulses under study will be equal to audio and time will be determined by measurements or, as it proportsions1lno koe conversion coefficient N of the frequency divider, a lower limit of the investigated range of durations and impulsovR and speed employed in the device components, i.e. the maximum allowable value but f ,,. The invention includes a digital meter for the duty cycle of rectangular pulses, comprising a reference frequency generator, a pulse counter and a first key serially connected in a ring, a frequency divider, a trigger and a second key, the output of which is connected to the input of a pulse counter, characterized in that , a frequency divider with a controlled division factor and a pulse duration measuring unit, the input of which is connected to the second input of the first key, are entered into it, the first output is connected to the second th trigger input, and the remaining outlets - connected to inputs of the frequency divider with a controllable dividing ratio, through which the reference frequency oscillator output is connected to the second input of the second switch. . Sources of information taken into account during the examination 1. Electron-counting frequency meter 43-34А. Technical description and operating instructions. 2. USSR author's certificate I 376728, cl. G 01 R 23/02, 1973.