SU1718137A1 - Device for continuous measuring of frequency of pulses - Google Patents

Abstract

The invention can be used to trace frequency measurements. The device contains a crystal oscillator 1, a divider 2 with a variable division factor, n reversible counters 3, n-1 correction pulse shaping units 4, a division unit 5 on a reversible counter, a control signal generation unit 6, an inverter unit 7, a division unit 8, an indicator 9 parallel code. 2 Il.

Description

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The invention relates to electroradiation measurements and can be used to trace pulse frequency measurements;

The purpose of the invention is to improve the accuracy of frequency measurement.

FIG. 1 and 2 are given, respectively, structural diagrams of the device and the inverter unit included in it.

The device for continuous measurement of the pulse frequency comprises a crystal oscillator 1, a divider 2 with a variable division factor, n reversible counters 3, n-1 correction pulse shaping units 4, a division unit 5 on a reversible counter, a control signal generating unit 6, an inverter unit 7, block 8 division and indicator 9 parallel code.

The output of the quartz oscillator 1 is connected to the input of a divider 2 with a variable division factor, the control inputs of which are connected to the outputs of n reversible counters 3 and the inputs of the indicator 9 of a parallel code. The device input is combined with the input of block 8, the first input of block 5 and the summing input of the first reversible counter 3, the subtracting input of which is combined with the output of divider 2, the second input of block 5 and the first input of block 6 of generation of control signals. The second input of block 6 is connected to the output of block 8 dividing, and n outputs are connected to the inputs of inverter block 7, the first and second additional inputs of which are connected to the first and second outputs of block 5. The first and second inputs of each of the n-1 correction pulse shaping blocks 4 connected, respectively, with the outputs of the transfer and the loan of the previous reversible counter, and the first and second outputs - with the summing and subtracting inputs of the subsequent reversing counter, while (n-1) - the output loop of the inverter unit 7 is connected to additional pairs input frames of the corresponding blocks 4.

The device works as follows.

The frequency of the faux pulses at the output of the division of bodies 2 with a variable division factor is determined in accordance with the formula

fe "x - fc

m KG

where fo is the frequency of the pulses at the output of the crystal oscillator 1;

N is the capacity of the divider 2;

m is the value of the control signal.

For the circuit shown in FIG. 1, the divisor 2 is equal to 4p, then if n b, then

23

m T2JDj with Dj - O V 1 and j - 0-23.

In the loop of the tracking system of the correction pulse shaping unit 4, implemented, for example, on two elements 2I, in addition to transmitting transfer pulses (loan), respectively, between reversing counters 3, they also transmit

Q transfer (loan) pulses from the outputs of dividing unit 5 on a reversible counter, arriving at the inputs of correction pulse shaping units 4 through inverter unit 7, depending on the state of its control code OJM (j 0.5). formed block b forming control signals.

This ability to transmit transfer pulses (loans) allows

Q correction of the control code Dj (| 0-23) not only from the low-order to the high-order by sequential transfer of transfer pulses (loan) between reversing counters 3, but also by direct recording

g pulses of transfer (loan) from the outputs of dividing unit 5 on a reversible counter immediately to higher bits of the control code Dj (0-23).

This allows to significantly reduce

Q is the time constant of the device when transients occur.

In the steady state, the frequency fnbix of the pulses at the output of the device is equal to the frequency f of the pulses at its input. Wherein

c the equilibrium state of the control code Dj (j 0-5) is determined from the equation PM f

Yours - and with fBbix f.

Q where PM is the control signal corresponding to the DJM control code (Q 0-5) with the capacitance No,

K is the division factor of the frequency f of the input pulses by the dividing unit 8 (by 5 example, K 2).

When the error A f out - f, caused by, for example, a change in the frequency of the pulses of the input signal, occurs, the control code changes

0) 0 0-23) generated by reversible counters 3, since their counting inputs and counting inputs of block 5 will receive a different number of pulses per unit of time,

5 Changing the code Dj 0 0-23) on the control inputs of the divider 2 with a variable division factor leads to a change in the frequency of the fobix pulses at the output of the device in the direction of reducing the mismatch DI. Control code D | Cl- 0-23) in

the steady state is proportional to the frequency f of the pulses of the input signal and is transmitted to the inputs of the parallel code indicator 9 for indication.

The dividing unit 5 on the reversible counter is designed to reduce the frequency of the device input pulses and the output pulses of divider 2, as well as create a relay static characteristic with deadband L. The formation of such a zone eliminates the influence of the fluctuation component of the sequence of input pulses on the operation of the device. Block 5 can be implemented on the basis of a reversible counter with summing and subtracting inputs, any output pulse of which (transfer or borrowing) after passing through element 2I affects the synchronization input of the recording of the fixed code of this counter.

Low level transfer (loan) signals from the outputs of block 5 are further processed by block 7 of inverters, taking into account the control code DJM (j 0-5) from the outputs of block 6 of generating control signals.

The control signal generating unit 6 is designed to generate a DJM control code (j 0-5) and is a tracking system and partly a model of the device in FIG. 1. Block 6 can be implemented on the basis of a reversible counter, the outputs of which are connected to the control inputs of a divider with a variable division factor, while its output is connected to the subtracting input of the reversing counter. The impulses of the frequencies of Thyx and fux / K are supplied, respectively, to the clock input dividers and summing input of the reversible counter, the outputs of which are connected to the inputs of the inverter unit 7. The time constant of block 6 may be several orders of magnitude shorter than the time constant of the device, made without blocks 4–8. The deadband of unit 6 eliminates the influence of noise imposed on the useful signal on the operation of the device in the steady state.

The inverter unit 7 (Fig. 2) is designed to distribute transfer (loan) pulses from the outputs of dividing unit 5 on a reversible counter between the correction impulse generation units 4 depending on the state of the control code DJM 0 0-5) generated by the unit 6 generation of control signals.

Block 7 of inverters contains elements 2И-НЕ 10 and elements OR 11. A necessary condition for the occurrence of transfer pulses or a loan (0-4) low level at the outputs of block 7 of inverters is the presence of clock pulses at the outputs of block 5. A sufficient condition for impulse transfer phenomena is

5 DSM 1, DIM, i.e. the excess of the control code Dj (J 0-5) equilibrium, and a sufficient condition for the occurrence of loan impulses is DS 0. Dj - 0, i.e. the DJM control code (j 0-5) is less than the equilibrium state for the corresponding values of X 0-4.

Thus, when the mismatch increases, the FREQUENCIES of the INPUT f and OUTPUT feux

impulses, the constant time of the device decreases due to the direct recording of transfer (loan) pulses, jЈ0-4, immediately to the higher bits of the code Dj (j 0-23), which leads to a reduction in the time of transient processes, and 0, the mismatch of the corresponding frequencies is an increase in the time constant of the device to reduce the measurement error.

A device for continuous frequency measurement in comparison with the known one makes it possible to improve the accuracy of measuring the frequency of input pulses with superimposed noises while simultaneously increasing the speed.

Claims (1)

0 claims A device for continuous measurement of the frequency of the pulses, containing a series-connected crystal oscillator and a divider with a variable division factor, as well as a parallel code indicator and parallel meters, whose outputs are connected to the corresponding control inputs of the variable split ratio indicator and the parallel code indicator inputs, wherein the output of the variable division divider is connected to the subtractive input of the first reversible counter, the summing input of which is 5 with the purpose of improving the accuracy of frequency measurement, n-1 correction pulse shaping units, a division unit on a reversible counter, and a control generation unit were added to it to increase the accuracy of the frequency measurement. Signals, a dividing unit and an inverter unit, the 1p inputs of which are connected to the corresponding outputs of the control signal generation unit, the first and second 5 additional inputs are connected respectively to the first and second outputs of the dividing unit on a reversible counter, and n-1 pairs of outputs are connected to additional pairs of inputs of the corresponding correction pulse shaping units, with input the device is connected to the first input of the block of each block of the formation of pulses of the dividing counter and the corrections are connected respectively to the unit; they are connected to the second input of the transfer and loan of the previous unit of the control signaling counter of the counter; , the first input of which is connected to the second- outputs of each block of formation of the division block on the reverse pulses of the correction by its own input are connected to the counter and the subtractive input of the first switch but to the summer and itayuschim versivnogo counter inputs, the first and second subsequent WMOs-down counter.