SU922654A2 - Device for measuring non-stationary random train pulse average frequency - Google Patents

Description

one .

The invention relates to a pulse technique and electrical measurements, in particular, to devices for measuring the average frequency of a non-stationary random flow pulses.

According to the main author. St. No. 673933, a device comprising two difference calculating units, a frequency divider, a threshold element, the inputs of which are connected to the outputs of the first difference calculating unit, the first and second switches, the control unit connected in series and the rewriting unit, the second and third inputs of which are connected to the outputs of the second differential counting unit, and the two outputs of the block re-. records are connected to the first and second inputs of the first difference calculating unit, the third and fourth inputs of the last are connected to the outputs of the first switch, the first input of which is connected to the second output of the control unit, the second input to the device input, the third input to the third output first

differential input unit and the first input of the second switch, and the fourth input is connected to the input of a frequency divider, the output of which is connected to the second input of the second switch, its outputs connected to the inputs of the second differential counting unit, and a pulse generator, rewriting, connected between the output of the threshold element, the third output of the control unit and the input of the frequency divider, as well as the unit for adjusting the division factor, the first input of which is connected to the fourth output of the control unit, the second input is connected to the output torogo difference counting unit and an output coupled to the input divider utravl yuschim Ll frequency.

This device is intended to measure the average frequency of a non-stationary random flow pulse. However, the measurement accuracy is not high, since it is the filter of the first ps series. In the event that the nonstationarity of the input stream begins to appear during the tact time, then even at a linearly increasing average frequency, the dynamic error will be significant. “The purpose of the invention is to improve the accuracy of measuring the average frequency of a nonstationary random flow. The goal is achieved by the fact that a unit for estimating the frequency increases in the unit has been entered into the device. the sign and informational outputs of which are connected. to the third and fourth inputs of the second switch, the first input of the average frequency increment estimator is connected to the fifth output of the control unit, the second input is connected to the output of the rewriter pulse generator, and the third input is connected to the third output of the first difference. full counting unit. FIG. 1 shows a structural circuit; in fig. 2 and 3 - timing charts, device operation. The device contains an infringement block 1, an overwriting block 2, a first switch 3, a rewriting pulse generator 4, a division factor adjustment block 5, a center frequency increment evaluation block 6, a second switch 7, a first difference counting block 8, a frequency divider 9, a threshold element 10 and a second differential counting unit 11. In the set-up mode, before the start of the new clock cycle, in the average frequency increment estimation unit 6, the average frequency increment evaluation code is stored. in one clock cycle, in the second difference counting block 11, the average frequency estimate code for the beginning clock, which represents a sum of evaluation codes for the increment of the average frequency with the average frequency estimate. The same code, but with a negative sign, is recorded in the first difference calculating unit 8. With the beginning of a new input pulse flow, the first switch 3 opened by the signal of the control unit 1 (Fig. 2a) is fed to the addition input of the first difference counting unit 8 .. Thus, after the window of the Time interval T, l in the first difference calculating unit 8, the shape of M1 is the difference between the predicted estimate, the average frequency, formed at the end of the previous path, and the result of the measurement in a given clock cycle. Then, for a time T, (FIG. 26) J OHCXO, adds the number stored to the beginning of the clock in block 6 for estimating the average frequency gain, with the average frequency stored in the second difference calculating block 11, Addition is carried out by a sequential number - a pulse code, which through the switch 7 enters the positive or negative input of block 11 depending on the sign of the number stored in block 6. Moreover, the value of the average frequency tfraction evaluation code in block 6 after the completion of the addition operation; it is. After that, the number written in the difference calculating unit 8, mth; formed in time Tg (Fig. 2c) into a serial number-pulse code, which is divided by frequency divider 9 and added up to a switch that is wounded in the second difference calculator 11. This happens as follows: The signal of the rewriting pulse and its pulses through the frequency divider 9 and the second switch 7 are fed to the input of addition or subtraction of the second difference calculating block 11, depending on whether a positive or negative number was written in the first difference counting block 8. Impulse The fourth generation bins also go through the first switch 3 to the input of the first difference calculating unit 8. If a positive code is written in it, then the pulses go to the input of the subtraction, if negative, then add to the input. In this case, the code of the first differential counting unit 8 is written down to zero, fixed by the threshold element 10, which includes the generator 4 of the rewriting pulses. Thus, generator 4 generates a number of pulses equal to the absolute value of the code of the first differential counting unit 8. As a result of adding the code of the first differential counting unit 8 with the code of the second differential counting unit 11, a code is formed in the latter that is proportional to the average frequency of the input pulse flow, extrapolated for the next measure. The pulses from the output of the generator 4 are also fed to the input of the block 6 of the evaluation of the completion of srets, her frequency. Since the number of pulses from generator 4 is the difference between the estimate of the average frequency obtained by one time equal to one cycle, more precisely, aa time Tn and the estimate extracted for this cycle and obtained taking into account all the history based on the data of the average frequency block 6, difference) do

keeps information on how much the evaluation of the average frequency increment differs from the true average frequency of the average frequency for the measurement cycle in question. In block 6 occur. the weight summation of this difference, taking into account the sign, with the previous value of the average frequency reduction code. As a result, we obtain the new value of the estimate pry5) as the average frequency.

Next, during time T, (Fig. 2d), the division factor adjustment block -.5 changes the division factor of frequency divider 9 in accordance with the average frequency estimate at a given cycle, and the rewriting unit 2 rewrites the code of the second difference calculating unit 11 into the first difference calculating Bq 8 with a negative sign, thereby preparing the next measurement cycle. This completes one measurement cycle.

The operation of the device during the next clock cycle does not differ from the previous one.

Tact time is

, T., TTj,. then in FIG. 2 and 3, since T Т T -, .T2 tfin is that, Thus, in the second difference calculating block 11, an estimate of the average frequency is formed, And in block 6, the estimate of 1 average frequency, i.e. estimate the rate of change of the average frequency. If the input signal has a constant frequency, then there are no fluctuations in the input stream. At the same time during the TP in the first difference calculating unit 8 is always. the same number of input pulses is recorded. The same number will be recorded in the steady state and in the internal difference calculating unit 11, so that the measurement error of the average frequency at the output of the first difference calculating unit 8 in the steady state jpaa is zero. FIG. 3 shows the belt

The diagrams for establishing the average frequency Xt | In the second difference i calculating block 11 and estimating the speed and average frequency t block 6, estimating the average frequency increment with an intermittent impact on the input of a pulsed flow device with a constant frequency Lo. In the steady state, the estimate of the average frequency A. Lo, and the estimate of the rate of its change is zero. When constructing the time gaps of the transition process, there were zero initial conditions, i.e. at the beginning of the first clock cycle, the content in the second difference calculating block 11 and block 6 of the evaluation of the average frequency increment is zero. The construction of diagrams is carried out in accordance with the description of the device operation. Dotted lines connect the estimated points.

Claims (1)

The inclusion of new elements in the original device distinguishes it favorably from the well-known one, since it makes it possible to increase the accuracy of measuring the current value of the average frequency. Apparatus of the Invention A device for measuring the average frequency of a non-stationary random flow pulses according to ed. St. No. 673933, characterized in that, in order to improve measurement accuracy, an average frequency increment estimator is introduced into the device, the sign and information outputs of which are connected to the third and fourth inputs of the second switch, the first input of the average frequency increment estimator is connected to the fifth the output of the control unit, the second input is connected to the output of the overwrite pulse generator, and the third input is connected to the third output of the first differential counting unit I. Sources of information taken into account during the examination . 1. USSR author's certificate No. 673933, cl. G 01 R 23/02, 1978. FIG 2