SU455346A1 - Apparatus for determining repetitive time intervals - Google Patents

Description

one

The invention relates to the field of impulse technology, namely, devices for determining repetitive time intervals and can be used in those areas where it is necessary to measure repetitive time intervals or other quantities that are converted into a time interval, and ananrimer, in phase measurements , when measuring electrical nanarazh, current, temnetureury and t. And.

Devices are known for measuring duplicate, their time intervals, based on the successive counting method, vernier stroboscopic and other methods. Of particular interest are devices based on the statistical test method (Monte-Carlo method), which is used to measure repeated time intervals, mostly of small size.

They contain a random generator, a logic unit for detecting the occurrence of at least one random impulse per measured interval, gates, a count of favorable outcomes, a shaping circuit, a steering circuit, a reset circuit, and a count of test numbers. This device differs from other known devices in that it imposes no restrictions on the nature of the flow of information being measured;

The 1II diaazone measurement and does not contain high-speed nodes.

However, the use of two counters of significant capacity and a special control circuit required for tightly synchronizing the operation of all nodes complicates the device and reduces its load-bearing capacity, especially when it is available.

The purpose of the invention is to increase the reliability and accuracy of the device.

This is achieved by using two logical blocks used for combining measured and random pulses and a unit for measuring the intensity difference (VID) of random pulsed currents, and a randomized state generator (GSP) is used in the GSP with a regular and intensity (among frequency).

FIG. 1 is a block diagram of a device for measuring time-varying time intervals; on fng. 2 and the probability distribution of the simplest pulsed foot is proved; on fng. 3 shows a time diagram, a flat pattern, and operation of the device.

The block diagram contains the generator 1 of a random stream of pulses; source I1k 2 of the current of pulses, the duration of which is measured; Logical block 3, used to detect cases of no random impulses falling on the measured time interval; logic unit 4, which detects the occurrence of exactly one pulse per measured interval; unit 5 for measuring the difference in the intensities of random pulsed flows; 6 - 9 - logic “And matches; differentiating Tses 10 and 11; logic circuits 12 and 13 of the ban; delay chains 14 and 15 and triggers 16, 17 and 18. The random flow generator and the source of the pulse flow of measured duration are connected to the inputs of logic blocks 3 and 4, and the outputs of the last blocks are connected to the inputs of the intensity difference measurement block 5. Logic block 3 contains a coincidence circuit 6, to the inputs of which are connected a geyrator 1 n source 2 measured and interval. The output of circuit 6 through the inhibit circuit 12 is connected to one of the inputs of the trigger 16, the outputs of which are connected to the inhibit circuit 12 and to one of the inputs of the coincidence circuit 7. The output of circuit 7 is connected to the first input of unit 5. A differentiated output of circuit 10 is connected to the second input of circuit 7, which is simultaneously connected via delay circuit 14 to the second input of trigger 16, and the input of circuit 10 is connected to source 2 of measured intervals. Generator 1 and source 2 are connected to the inputs of the coincidence circuit 8 and the output of circuit 8 is connected to one of the trigger inputs 17, the KOTOjioro outputs are connected (R; 1 to the trigger input 18 (the output of which is connected to the second inhibit circuit input 13) and to one of the inputs of circuit 9 sovnade1N1, the output connected to the second input of block 5. To the second input of schelga 9, there is a differential output 11, which is alone through the delay circuit 15 of the switch to the second inputs of the trigger 17 and 18, and the input of the circuit 11 of the switches to source 2. The principle of operation of the device was Novel on the following mathematical relationships. It is assumed that the random impulse flow generated by generator 1 is a stationary simplest (Poisson) flow. For such a stream, the probability of hitting exactly /// pulses of this stream and a certain given time interval is determined by the relation where m 0, 1, 2, 3, ...; ) - - Density (intensity, average frequency) of the most elementary etacion and air flow. The time interval t in expression (I) is assumed to be equal to the measured time period and the interval. In a nutshell, FIG. 2 shows a plot of Yat-: / (, -) ..,. „„ ,. | in accordance with the expression (1), where /., the probability of getting exactly t random pulses per measured time interval (t (, 1, 2, 3 ...); / V is the average frequency of the random flow; t is the measured interval: the graph shows the following, and the regularity: the intersection points of adjacent red (corresponding to adjacent values of n) correspond to integer values of the argument:, moreover, the intersection point of some arbitrary k-th curve with (kI) curve (otherwise, the probability equality point P / i} - k (k 1, corresponds to the value, ...). Proceeding from expression (1), for t k n k - 1 field they read: (Lt) -1 (ii 1,2,3, ...) With comparative expressions (2) n (3) it can be seen, then equality of functions (2) and (3) takes place with k. On the basis of this, The time interval is measured in (2), (3), and (4) fixed and equal to the measured value by adjusting the intensity of the random flux l to achieve equality of the expressions (2) and (3) p k. k- ,. Further, find the desired time interval ------ (A 1, 2, 3, ...) (6) / 1, for the measuring device can be used more than equal equality and high probability. s p ,. n .-- / l7 (/ g; / 7), nanorimer / Jo-,, n /; s ,. , and so on This is evident from FIG. 2: any curve is not cut off not only from the adjacent, but also eo by all the other curves of the family, and the intersection points are uniquely associated with completely definite values of the argument / -T, and therefore also t. The analysis has shown that in the case of the dagnum one can increase the accuracy of the measuring device. However, from the point of view of simplicity of technical implementation, it is more expedient to use the following tea of the adjacent probabilities / ;, and Ph, Since it is impossible to give the device diagram e, 1 and |) the arbitrary value of the parameter k, while maintaining sufficient accuracy and co-secrecy, scheme, corresponding to a / g 1. The scheme works in the following way. At the inputs of logic blocks 3 and 4 from the generator I and OLT. There is a stationary and i) a simplest random current of short pulses (o - pulses). The geierator 1 provides for the possibility of smoothly adjusting the intensity of the / - flow. The other inputs of the 3 n 4 blocks from the source 2 receive a stream of rectangular pulses, the duration of which is not measured (depending on the specific circuit realgization of the losses, the flow can be represented directly measured by the time interval set by short-term impulses).

Ma fng. 3 prvedepa time diagram of the device, where:

and - the signal at the output of the random flow generator;

and - pulses of measured duration;

Uz is the signal at the output of logic block 4;

Un is a signal at the output of a logical unit 3. The flow Uz may be pro-randomly regular or occasional, and the requirement of its stationarity is not necessary. Let the average intensity of this flux be AI. If during the time of the sequence of the flow measured by the pulse pulse Ui and the input of block 3, no random flow pulse comes from generator 1 (if no incident pulse falls on the measured interval), after this interval at the output of the block 3 impulse occurs. Block 4 forms nmnulses at its output in those cases when even one random pulse falls on the measured interval. Block 3 works as follows (t 0).

The flow of pulses from the Nostunet generator 1 to the input of the coincidence circuit 6, and its other input from Source 2 is fed with a stream of pulses of measured duration. During the next measured pulse, the AI of one impulse from generator 1 did not arrive, the outputs of circuits 6 and 12 appear and the trigger 16 remains in its original state, while the high potential ("1) of its right shoulder is present at the input circuit 7 during the whole time interval of the measured interval. At the moment of the end of the last, the differentiating circuit 10 forms a pulse, which is received from the second input of the coincidence circuit 7; since its first input is “1,” at the output of circuit 7, i.e., at 5 | of the entire block 3, a signal appears indicating that not a single random impulse has occurred during this time interval.

If during the measured interval from the generator 1 is irnable one (nerve) impulse, the output of circuit 6 causes a cnnal, passage through the normally open circuit 12 of the prohibition on the input of the trigger 16 and the drive; it to another stable state 1P1e. At the same time, the potential at its right shoulder and at the input of circuit 7 becomes monitored ("O), the 1-pulse from the differential circuit 10 and the second input of circuit 7 at the time of the end of the measured interval, and the output of circuit 7 (and the whole block 3 ).

At the moment of transition of the trigger 16 to another stable state, the high potential of the spruce shoulder arrives at the second input of the prohibition circuit 12, which excludes the possibility of passage of signals to the input of the trigger of the trigger 16 in the event that the measured interval

gets more than one pulse from the generator 1. The falling edge of the measured pulse from the output of circuit 10 through the delay circuit 14 sets the trigger 16 to its original state, prepared by the circuit of block 3 for the arrival of the next 1, its measured NMR pulse (the delay circuit is necessary for In order to determine the possibility of a missed information inflgatsin about the state of 1 and the trigger in the moment of the end of the measured imiuls).

The operation of unit 4 is derived in the following way (t-1).

The structure of block 4 is the logic of its operation analogous to block 3. The difference consists in adding one more trigger 18 (which, together with the nerve trigger 17, forms a two-bit counter) and corresponds to 1; H3N eHeHHn some of the bonds between the element. Essentially, during the valid interval interval and at the input of the joint circuit 8, its second input comes once at the output of generator I, on the output of circuit 8, the signal does not appear, and the counter remains in the initial state. This low iotantal (“O) from the left nlec of the thrunger 17 is not present at the input of circuit 9 for the entire time of the measured interval. Owing to this, the rear front of the pnum pulse, which is measured by the duration, which is not from the output of the differing value 11 to the second input of circuit 9 passes through the output of circuit 9 (output of the whole block 4).

If for the measurement interval of the transfer of one (random) random NMR pulse, on the output of the circuit 8 there will be a signal. which nostunet through the open circuit 13 to the input of the trigger 17 and the hierarchy of it to another stable state. This high note, occurring on the left side of the trigger 17, is fed to the input of circuit 9, which allows the front of the measured n-pulse to be output to the output of circuit 9.

In the case when, during the paccMaTpimaeNioro time of the measured impulse (interval), a second impulse from generator 1 arrives, a second impulse appears at the output of circuit 8, which, having passed through the circuit 13, triggers the trigger 17 to the outgoing state, and the trigger 18 -R new 1H1e state (the number 2 is fixed in the counter), When this is on the left shoulder of the trigger 17 (at the input of the circuit 9), the initial io- eticial reappears, which excludes the possibility of a hatch signal at the output of the block 4 but at the end of the measure emo1CH) N1ggervala.

At the same time, the high potential from the left nlek of the 18 nostuna trigger and the second (alarm) input of the schematic 13, and the current pulses from the output of the circuit 8 and the counter are not possible, if during the measured interval from the generator 1, the third, fourth, and t, D. Impulses.

The circuit 15 n svnnu, providing reset of the counter, fuiktsinoinut as well as n n block 3.

In the case (for pierced in k), the logic block circuit must contain counter capacitance. ,, k + 1, descrambler

7 code that permits the passage of a pulse to the output, if the counter contains a / g emulsion, and a prohibition scheme that blocks the input of the counter, if it contains k + 1 emuls. Thus, at the outputs of blocks 3 and 4, there are formed emulsified currents, random for moments but not equal to 1 nm pulses (Fig. 3). The average and intensity of these currents is:; -U L, t h-h, /. L / -3 - interactivity of the current at the output of block 3; / -4 - average intensity of the current in the output of block 4; (I) the average titosity of the current of measured imulses. / L ,, 7 PI .--- probability of ionization and, respectively, of O and 1 random imiuls per measured interval. Subtracting the expression (8) from the expression (7), and the law participates: /,,--),,--./,,ERTЯ,.- I, O, (9) where did p ". Formulas (10) imply that the difference between the probabilities under consideration and -Pi, and the world-wide differences between the mean intensities AZ and}. notes at the outputs of logical blocks 3 and 4. From this it follows that the condition of equality of probabilities (5) is satisfied when the difference I1 of the heatsivities /,;, - /., –O becomes equal to zero (11) The difference between the interactivities is fixed with of block 5. Smoothly adjusting velcciu yiteyshivosti-iotoka from geyirator 1, iodnut such a value A, at which block 5 fixes the equality of integrities (11) of the legs and outputs of blocks 3 n 4. At the same time, relations (4) n (5) are fulfilled, and the magnitude of the measured interval. The time is 1ggs in accordance with the formula (6 ) from the expression The geirator's scale can be calibrated in units of - or directly in units of measured magnitude. As expressed from (6), the value of / e can be chosen for any natural number (except / g 0). The co-critical value of k is determined by the norm of the measured magnitude and the possible limits of the intensity regulation /. flow from the generator 1. Since the proposed device is more efficient when measuring short time and thermal intervals, it is not advisable to choose too large values of / g, since this requires an increase in the intensity / .. In addition, the increase in k complicates the structure of logical blocks 3 and 4. As The unit for measuring the difference of fluorescence 5 in the device is advisable to use a circuit, the advantage of which is the independence of the measurement error from the value of the measured difference of the intensities. This is especially important for a daniy device where it is required not to measure the difference at all, but to estimate the small deviation of this difference from zero. The condition of "equilibrating the device (the equality of the corresponding probabilities and the iterations) is the relation (4). This expression does not contain /. —Inggeyshivosti of the current of time intervals. This leads to an important iracical conclusion that this HirreiicHBiiocTb can be unstable, i.e., the current setting the measured intervals can be instarially. In the particular case when this note is regular (as is often the case), the frequency stability (/.;, / C) and the current is sometimes hard to meet. It is necessary to ensure only a sufficiently large value of the graphical position, since the latter, as seen from expression 1 (9), determines the sensitivity of the device: the higher the /.ts, the greater the difference between the inputs and the input of block 5, caused by the difference of probabilities. From the initial operation of the proposed device, it follows that the measurement time is not rigidly fixed, as is the case in the known device. The required measurement time, the decisive accuracy, is determined by the choice of the intensity / sec and the unit 5 timestand. There are no elements in the device, which reliably fix the operation of the device (control circuit, valves, test number counter, etc.), and the necessary in the prototine. The advantage of the device is also to reduce the requirements for the stability of the intensity of the random current from the geyrator 1. State /. There should be only a small amount of time, which, when measuring small intervals, is small enough (it can not exceed 0.1 - 1 second). This is the image, but the note from the geyrator of 1 dol / ken is to be the stationary time limit and limited time intervals. This is essentially UnroI1, the co-construction of the geierator. In addition, for the proposed device, the methodological inherent accuracy of the measurement is independent of the size of the nortal time interval. The ethnology of the device is achieved not due to the complexity of the design, but as a result of a different ipoption of the structure, allowing us to simplify the costructuring of the device. As well as research, the device has rather high metrological characteristics. Thus, measurement of time intervals in the range of 1.1 - 10 microseconds can be performed with a relative error of 3-: 0.5% (reliability 96.0%), and the measurement time in the specified range of interval variation is t, i3M 00 , 6-6 seconds (provided that the ratio of the measured flow is Q 2), and the intensity of the random flow is regulated within /, 10 1 / s.

Subject invention

A device for determining repetitive time intervals, comprising a geyrator of a random stream of pulses, a logical block, a source of a stream of measured intervals, characterized in that, in order to increase the reliability and accuracy of the device, the OIO contains a block for measuring the difference of intensities and an additional logptic block, the first the input of which is connected to the source of the flow of measured eryx intervals and to the first input of the logic unit, the second input of which is connected to the generators of a random current and to the second input of the additional unit Nogo logic block, logic block outputs are connected to unit measuring the difference inteisivpostey.

tlJULU

„TL.

L

I

I

L

i

I I j I

one

i