SU790269A1 - Digital analyzer of frequency and number of pulse trains - Google Patents

Description

(54) DIGITAL ANALYZER OF FREQUENCY AND NUMBER OF PULSE SEQUENCES

I

The invention relates to a pulse technique and is intended for use in automation devices, in particular for counting a predetermined number of pulses in a given frequency range.

A device is known for analyzing (classifying) the duration and number of pulses, based on measuring the duration of the pulses and then counting the pulses of the same duration in a pulse train. The device consists of a pulse width meter, built on a delay line with taps, to which a combination of logic circuits AND is connected, whose outputs are connected to an organ for counting pulses of the same duration 1.

The disadvantages of this device are the inability to directly measure the pulse repetition rate and count the number of pulses of any duration of a given range; low resolution of measuring pulse durations in a given range; impossibility of smooth adjustment of the upper and lower limits of the working frequency range (duration).

Also known is a digital frequency filter of repeated pulses with continuously adjustable upper and none;: -; its passband boundaries, based on a comparison of the duration of the analyzed pulses with reference pulses produced by the single vibrators of the lower and upper passband limits. This device contains a single upper-frequency repetition single-vibration, whose inputs are respectively connected to low-repeat single-shot single-vibration inputs, as well as to two logic circuits AND, whose outputs are connected to the common input of the device and one of the inputs of the third cxer. The outputs of one-vibration are connected to other inputs of this circuit, and its output is connected to the input of the alarm trigger 2.

The disadvantages of this device are the inability to count a specific, predetermined 2S number of pulses in the analyzed pulse sequence; the impossibility of separating at the output of the first and all subsequent odd pulses for their further counting with an additional device, which

reduces the accuracy and reliability of measurement when working in the low-frequency region in units and tens of hertz; the presence of a mechanical device for smooth adjustment of the upper and lower limits of the repetition frequency, reducing the reliability of the device and increasing its dimensions and weight; the inability to automatically turn off the alarm device when the next impulse-sequence arrives at the circuit input; the need to reset in one-shot one.

The purpose of the invention is to improve the measurement accuracy while expanding the functionality.

The goal is achieved by the fact that the digital analyzer frequency and the number of pulse sequences, which contain single vibrators of the upper and lower repetition frequency limits, the AND-NOT element, the OR element and the alarm trigger, are entered with the two IS-NOT elements, the OR element and the counter, with the inputs one-shot upper and lower boundaries of the repetition frequency are connected to the first inputs of two NAND elements, the second input of the first one is connected to the output of the single-vibrator upper limit of the repetition frequency, and its output is connected to the counting input with and the second input of the second NAND element, the output of which is connected to the first input of the first OR element, the second input of which is connected to the output of the one-vibrator lower limit of the repetition frequency, and the second input of the second OR element, the first input of which is connected to the unit output counter, to the installation R-input of which the output of the PN element OR is connected, and the output of the number n of the counter is connected to the first input of the third AND-NOT element and to the counting input C of the alarm trigger, the installation input To which is connected to the output of the second element OR, and the output is connected to the second input of the third element. AND-NOT, the output of which is connected to the third input of the first element OR.

Fig. 1 shows the block diagram of a digital frequency analyzer and the number of pulse sequences; in fig. 2, 3, and 4 are timing diagrams that show how the analyzer works.

The digital pulse sequence analyzer contains a single-shot 1 upper limit of the repetition frequency, a single-shot 2 lower limit of the repetition frequency with an input delay, logical gates of AND-HE 3, 4 and 5, logical gates of OR b and 7, a binary-decimal counter 8 with the specified counting coefficient n, trigger 9 alarm.

In the time diagrams, the voltage is indicated (, at the analyzer input, the voltage UQ at the output of the one-vibration 1, the voltage Ucvo. At the output of the one-vibration 2, the voltage Uc at the counting input of the counter 3, the voltage Un at the n-output of the counter 8, the voltage Un-on trigger output 9.

The digital frequency analyzer and the number of pulse sequences work in the following way.

The first pulse of the analyzed sequence (bundle) of pulses comes simultaneously to start one-shot 2 and 1 and to the first input of the element AND-HE 3, from the output of which goes to the record in the counter 8. After starting at the output of the one-shot 1, and hence at the second input A NE-3 element appears a timed pulse of duration f corresponding to the set upper limit of the bandwidth, and the one-shot 2 is placed in a delay mode of duration 1/2 corresponding to the lower limit of the analyzer's passband (yes neyshem i-l -. odnovi- pulse duration bratora 2) It should be noted that the first pulse is always supplied to the post in the counter 8 ,. since the duration of the launch of the one-shot 1 is longer than the length of the leading edge of the input pulse, therefore, the AND-NE 3 logic element is open at this time to pass the input pulse to the counting input of counter 8.

Let us consider the operation of the analyzer at three practically possible ratios between the duration of the timed pulses t, t of the single vibrators 1 and 2 and the repetition frequency (follow-up period) Tgy of the input pulses,

The repetition frequency of the input pulses is less than the duration of the timed pulses of the single vibrators 1 and 2 (Fig. 2)

Claims (2)

In this case, the occurrence of the next second pulse at the input of the analyzer is NOT-3 element 3 is in the closed state due to the presence of a one-vibrator 1 at its second input t and does not allow the input pulse to write to counter 8, the one-shot 1 and 2 are restarted, and the pulse duration is counted from the moment of arrival of this input pulse. In the counter 8, the previously recorded first pulse is erased by the circuits formed by the elements AND-HE 4, OR 6 and the R input of the counter 8. Thus, the output of the analyzer eliminates the signal. The repetition frequency of the input pulses is longer than the duration of the timed pulses of the multivibrators 1 and (Fig. 3) .. in this case, the next (second) pulse at the output of the one-vibrator 1 pulse t will not be at the time of arrival of the analyzer I-NOT 3 open. The single-vibration 2 returns to its original state after issuing a short pulse with a reset delay of counter 8 and trigger 9, i.e. the analyzer is found in its initial state, and each subsequent input pulse is treated as the first, and no signal appears at the output of the analyzer. The repetition frequency of the input pulses is longer than the pulse duration of the vibrator 1 and less than the pulse duration T, the one-shot 2 (FIG. 4 ILICH) In this case, by the time the next (second) pulse arrives at the analyzer's input, the output of the one-shot 1 pulse will not be AND-NOT 3 turns out to be open, therefore, this input pulse is recorded in the counter 8, the one-shot one starts up again, and the time delay T, the one-shot -2 starts from this point, the analyzer runs until the counter 8 is filled to the number n, then the trigger 9 is transferred to another stable state, and a signal appears at the output of the analyzer indicating the appearance of a certain number of pulses in the specified frequency range at the input. The output pulse of the trigger 9, the counter 8, along the circuits formed by the elements AND-HE 5, OR 6, the next n + 1 pulse is formed as the first, and the trigger 9 with the pulse from the single output of the counter 8 through the element 7 returns to the initial state, and the signal to the analyzer output disappears. Compared with the known technical solutions, the use of the analyzer to be used allows one to count a specific, predetermined number of pulses in a given frequency range and to extract and count all even and odd pulses, including the first one, which improves the accuracy and reliability measurements, especially in the field of low frequencies in units and tens of hertz. It lacks mechanical devices for the smooth adjustment of the repetition frequency boundaries, which increases reliability and reduces its dimensions and weight; one-shot have a simplified control circuit and do not require a reset to O. Claims of the Invention A digital frequency analyzer and number of pulse sequences containing one-shot upper and lower limits of the repetition rate, AND-NE element, OR element and alarm trigger, distinguished by the fact that , in order to improve the measurement accuracy while simultaneously expanding the functionality, two AND-NOT elements, an OR element and a counter are introduced into it, with the inputs of the single and upper combinations of the upper and lower limits of the connection repetition frequency Ina with the first inputs of the two elements IS-NOT, the second input of the first one is connected to the output of the one-vibrator upper limit of the repetition frequency, and the output is connected to the counting input of the counter and the second input of the second element AND-NOT whose output is connected to the first input of the first element OR, the second input of which is connected to the output of the one-vibrator lower limit of the repetition frequency, and with the second input of the second element OR, the first input of which is connected to the output of the counter unit, to the installation R-input of which the output of the first element L is switched And, and the output of the n value of the counter is connected to the first input of the third NAND element and to the counting input C of the alarm trigger, the installation input To which is connected to the output of the second OR element, and the output is connected to the second input of the third NAND element, the output of which with the third input of the first element OR. Sources of information taken into account in the examination 1. For the Germany, No. 2244955, cl. 21 a 42 e, pub. 1969. 2. US patent number 3383605, class. 328-138, published. 1968. ig.1 / g d And Htf t.t u, / fVi ri . Tgjf t3 Fi9. 3 and, W2 Hi tmi Tf 2 Yy fff