SU1287120A1 - Meter of transient characteristics - Google Patents

Abstract

The invention relates to a radio measurement technique. The purpose of the invention is to increase accuracy and enhance functionality. The transient response meter consists of a basic meter that contains the first, second and third pulse generators, N dividers with a variable division factor, a switching node, a switch, an adder, a synchronizer and a recorder, as well as two input and one output buses, and . it includes a reset node, N RS-flip-flops, N elements AND and two OR elements, and the number N is determined by the initial oscillation frequency under study and its variation during the transition process, as well as the duration of the latter and the permissible errors of its sampling in frequency and time. 8 il. i W

Description

u 00

112

The invention relates to radio measurements and can be used to study and control the dynamic properties of controlled self-oscillating systems, which include quartz and string sensors, as well as controlled quartz oscillators and other devices controlled by frequency.

The purpose of the invention is to improve the accuracy and functionality.

FIG. 1 shows time diagrams explaining the principle of transformation of the increment of the period or frequency of the signal under study in the voltage change; 2 is a functional diagram of the proposed transient meter; FIG. 3 is timing diagrams explaining the operation of the proposed transient meter} in FIG. 4 is a functional diagram of a divider with a variable division factor; in fig. 5 - functional layout of the reset node; in fig. 6 is a functional diagram of the switch} in Fig. 7 is a functional diagram of the adder; on Fig - restored functions of the transition process and short-term frequency instability.

-

In the proposed transient meter, to accurately restore the transient function of the frequency setting, the frequency or period oscillation is converted to a voltage change in a sequential order.

At the same moment of time, the interrogation interval (Fig. 1b) begins to form from the reference frequency pulses (4mg.1a), where K is the number of reference frequency pulses in the polling interval; X is the period of the reference frequency, and Ie of the pulses of the frequency under study (Fig, 1 s) is the interval under study (Fig. 1 d), where K is the number of pulses of the frequency under study in the studied interval; T is the period of the frequency under study, the measurement interval t is formed (Fig. 1 e) as the difference between the reference and the studied intervals, which commutes the pulses of the reference (Fig. 1 m) or frequencies under study (Fig. 1 t); the number of switched pulses is converted to voltage (Fig. 1 n, z), and each switched pulse corresponds to 202

There is a voltage increment per quantization step.

Thus, the increment of the period or frequency of the process under study using the proposed meter is converted into a sequence of voltage readings arranged in time at regular intervals

ODA

The type of switched pulses (Fig. 1 n, z) has a significant effect on the metrological properties of the meter, therefore, depending on their type, two modes of operation are possible: 1st mode - the reference frequency pulses are switched, the 11th mode switches the investigated pulses frequencies.

In order to assess the metrological properties of each of the modes, the change in the output voltage with a jump change in the period (dT) or frequency (uf) is determined.

1-mode operation.

Output voltage before voltage jump is equal to

and

you I

CoKT, t:

whether.

(one)

where t

To

- the initial value of the period

the studied frequency. After changing the period T by the value LT, the voltage (1) transforms to

and.

CoT „-K, T,

(2)

 Vb, X2 T

ABOUT

The dependence of the output voltage on the increment of the period aT in this case is

IV, whether

(3)

In order to simplify the calculations, the intervals tg and t, at the initial moment of time, are taken to be equal to each other, taking into account SOGU, i.e. K, T, KD; ,

... jj ratio

one.

one

L

T, + & T

T / + TX o o o

& t

(3) determine the dependence of the voltage on the increment

t, n. fo-

f, -if

whether.

(four)

where do you determine the resolution of the 1st mode in frequency, i.e. frequency deviation d corresponding to 312871

change in output voltage per quantization step

uf

 wg

ton. f. one

(five)

I1st mode of operation.

Similarly to the 1st mode, relations like (3), (4) and (5) are determined. Output voltage varies with period increment

tpnP t -T „LT

whether

and frequency increments

 tonp (7) Resolution of 11th mode:

fp. T-.)

op p

From relations (4-8), it follows that the 1st mode has a linear characteristic of the conversion period - voltage, the 11th mode has a linear characteristic of the frequency-voltage conversion; the resolution of the 1st mode is determined not only by the polling interval and the initial value of the frequency under study, but also by the value of the reference frequency, the resolution of the 11th mode is determined only by the interval of the survey.

The transient frequency setting function can be restored by linear interpolation within each polling interval, with the maximum value of the restoration error determined by

. K. „

(9)

-twKc - 8

where K is a coefficient taking into account the conversion of the frequency increment or period into a voltage change.

Reducing the error of recovery is possible by reducing the time interval between discrete voltage values ().

From Fig. 1 n, z it can be seen that during the measurement interval t the number of pulses is converted into voltage, and during the interval t the indication of the result obtained.

In order to increase the measurement accuracy by increasing the resolution of the meter between the pulses a b (Fig. 1n), N similar measuring devices are formed in a similar way.

12871

neither

(five)

204

pulses (ka of FIG. 1, conventionally, the formation of only one pulse is shown by lines). In this case, the number N is found from the condition

5Df i iq with ° pr ut. t.

(ten)

fO

Taking into account relation (5) and the fact that sampling errors by frequency § and time 5 are equal respectively

S 0

  .KC

about

(eleven)

15 5,

4t

where uf is the change of the studied frequency during the transition process;

ut is the duration of the transition process,

function (10) is converted to

f, -5,

f Si ". . .

 N

f "c-g. f. Af.

(12)

25

thirty

35

40

45

50

55

Outside of this interval, the effect of increasing accuracy does not reach c (f, fj.

Since there is no differentiation node in the proposed solution, which introduces a significant error in the discretization of nonlinearity and inertia Sj, and also the number of information points is increased N times, the accuracy increase in comparison with the known device can be achieved BN (1 + 6g) .

The transient response meter (Fig. 2) contains the first pulse shaper 1, N dividers 2, the first inputs of which are connected to the output of the first driver 1 of pulses, and the second input of the switching node 3, N RS-flip-flops 4, the first and second inputs of which are connected respectively to the outputs and the second inputs of the respective dividers 2. The output of the switch node 3 is connected to the first inputs of the N elements AND 5 | the second inputs of which are each connected to the output of the corresponding RS flip-flop 4. The inputs of the first element OR 6 are each connected to the output of one of the N elements AND 5. The inputs of the second element OR 7 are each connected to the output of one of the N RS-flip-flops 4. 8 is connected to the output of the second element OR 7.

51

The first and second inputs of the switch 9 are connected respectively to the outputs of the first element OR 6 and the second driver 8 pulses. The inputs of the adder 10 are connected to the corresponding outputs of the switch 9. The first input of the recorder 11 is connected to the output of the adder 10. The output of the third pulse driver 12 is connected to the input of the reset node 13, the outputs of which are connected each to the second inputs of the corresponding / RS-triggers 4 synchronizer 14 is connected to the second input of the recorder 11. The first and second input buses 15 and 16 are connected respectively to the inputs of the first 1 and third 12 pulse shapers, and the output bus 17 is connected to the first output of the synchronizer 11.

The second pulse shaper 8 (FIG. 2) is made in the form of a capacitor 18, a HE element 19, and a 2I-HE element 20. Divider 2 consists of binary counters 21, a crossover field 22, 8I-HE elements 23, and an IPI-NE 2 / element 2 J (figure 4).

The reset node 3 consists of a divider 2 with a variable division ratio, counting triggers 25, multiplexer selectors 26, and elements 2 and 27 (figure 5).

The switch 9 consists of binary counters 28 (FIG. 6), the adder 10 consists of the elements OR 29, the resistor R 30 and the resistors 2 R 31 (FIG. 7

The proposed meter works as follows.

Before the start of the measurement, the research institute determined by formulas (3) and (12)

are the polling interval t and the number N, Calculate the sampling interval

t.

At

 ,

 Oh-oh. J

WHAT allows you to choose the period of the frequency of the reference generator T and the coefficient

Cycle Kjj of node 13 of discharge.

The division ratio DPKD 2 choose from

  x XMoKci

where is the maximum value

l FldKC

the period of the studied frequency.

The signal is transmitted, respectively, from the first (reference frequency pulse) or the second (investigated frequency pulse) of its inputs.

The assignment of all nodes of the meter and the passage of signals are considered with one basic variant, i.e. when (the basic version includes one PDKD 2, one RS flip-flop 4 and one Elment 2I 5).

The pulses of the reference frequency (fig.Z, fd) from the second input bus 16 through the third driver 12 pulses arrive at the input of the reset node ,. At the first output of the resetting unit 13, a sequence of reset pulses is formed (Fig. 3.1), following with a polling interval t Kj T. The reset pulse sets the high pressure air pump 2 and the RS-trigger ger 4 to the zero state (Fig. 3c-1)

The pulses of the investigated frequency f (Fig. 3 f,) from the first input bus 15 through the first pulse shaper are fed to the first inputs of the DPDD 2 and the second input of the switching node. A setup pulse (Fig. 3 in-1) appears at the output of the PDCD 2 after the arrival of a reset pulse at time t. The pulses of the installation are fed to the first inputs of the RS flip-flops 4, while at its output a measuring interval is formed, the duration of which is equal to

t, t,

-t.

(14)

The measuring interval from the output RS-flip-flop 4 is fed to the second input of element 2 and 5, to the first input of which, depending on the mode of operation of the switching unit 3, pulses of frequency f or f are received.

At the output of element 2 and 5, pulses appear, the number of which is equal to

five

0

where t

-onf

-t.

T,

(15)

V

0, "

- the duration of the reference period or the studied frequency.

The pulses from the output of element 2 and 5 through the element OR 6 arrive at the first input of the switch 9, which interrupts the number of pulses into the code. Measuring interval from the output of RS-trigger 4 through the element OR 7 and the second

Depending on the required characterization of 8 pulses comes

The conversion characteristics j defined by expressions (3), (4), (6) and (7) set the I or 11th mode of operation of the switching node to the output of the switch to the second input of the switch for setting the last edge of the measurement interval to the initial (zero) state (fig. 3m

shaper 8 pulses arrives

so; ke to the second input of the switch for setting the last one on the leading edge of the measuring interval to the initial (zero) state (fig.3m).

71

The adder converts the code of the pulses into a voltage (Fig. 3n, z) formed during the measuring interval, and an increase in the code by one corresponds to an increase in the voltage per quantization step dC.

The output voltage of the adder

out

and bnplb di. (sixteen)

out T,

The synchronizer is designed to synchronize the start of operation of the meter with the filing time of the test effect on the object under study. The voltage from the output of the adder is fed to the recorder.

Thus, at the end of each polling interval on the recorder, a voltage appears that characterizes the increment of the period or frequency in the corresponding polling interval.

When forming additional information points, the proposed transient response meter works as follows.

At each of its outputs, a reset unit 13 generates a sequence of reset pulses following the polling interval, but each successive pulse is shifted relative to the previous one by the sampling interval dt (Fig 3.1 out, N out). Discharge pulses from each of the node outputs The 13 reset is set to the zero state corresponding to DPKD 2 and K5-trigger 4 (Fig. 3, c-1, CN). The pulses of the frequency under study (Fig. 3, f), from the first input bus 15, through the first driver 1 of the pulses, arrive at the first inputs of all DPCD 2, at the output of which, at time intervals t after the arrival of the corresponding reset pulse, installation pulses appear (Fig. 3 C-1, BN), which translate the corresponding triggers into a single state (FIG. 3 c-1, cN). At the output of each of the RS-flip-flops 4, a measuring interval t is defined by the relation (14), which is filled with frequency pulses f or f with the help of elements 2И 5. Using the first element N OR 6, the output signals of all elements 5 are summed (Fig. 3 d), as a result, at the output of element N IL 6, a sequence of 20 "

pulse check. Using the switch 9 and the adder 10, the number of pulses in the packet is converted into a voltage (FIG. 3 h), which is fed to the recorder 11 for control. Before the arrival of the next burst of pulses, the switch 9 is set to the zero state by the pulses formed from the measurement intervals of all RS flip-flops 4 by means of the second elements N OR 7 and the driver 8 pulses (FIG. 3).

Consequently, for any number of basic variants, the change in the period or frequency of the signal under study is converted into a sequence of voltage samples following the sampling pulse, defined by relation (13).

The work of individual complex nodes meter.

Divider 2 with variable division factor (figure 4).

Upon the arrival of the reset pulse to the second input of the DPDD 2, all binary counters on the outputs are set to the zero state, after which the binary code of the incoming pulses begins to appear on them for each frequency pulse arriving at the first input. On the cross field 22, a binary code of the number of pulses is set, which determines the division factor. At the output of element 2, IPI-NO 24 and PDCD 2, a signal appears only if all the inputs of elements 8I-NO 23, which are bridged to the corresponding outputs of the binary divider, have unit signal levels.

The reset node 13 (fig.Z).

Frequency pulses from the input are sent to the DPKD 2. From the output of the PDKD 2, the signal goes to a chain of serially connected counting triggers 25. The outputs of the first four triggers 25 are connected to the corresponding control inputs of the selector multiplexers 26. The outputs of the subsequent triggers 25 are connected to the control inputs of equal selector-multiplexer 26-1, the outputs of which are connected to gating the inputs of selector-multiplexers 26, which ensures their consistent operation. The binary code from the outputs of the first four flip-flops 25 by each of the selectors-multiplexers 26 is converted into a decimal code, which is fed to one input of the corresponding elements 2 and 27, to the other inputs of which are received the reset pulses from the output of PDKD 2.

Therefore, on the 1st exit.

N

howled

after

resetting impulses

Switch 9 (Fig. 6) consists of serially connected binary counters 28, the signal received at the second input sets binary counters to the zero state, after which the binary code of the number of pulses received at the first input of the switch appears at the outputs of switch 9; 9.

Summer 10 (Fig. 7) is a code-to-voltage converter based on the matrix R30-2R31. The voltage switching is performed by the elements OR 29.

Waveforms of the transient process of setting the frequency and form of short-term frequency instability are shown in Fig.8a, b.

Compared with the known device, the proposed transient response meter is characterized by N (1 + Sg) times higher measurement accuracy, which is due to the digital form of signal processing and an increase in N times the information points for frequency setting, broader functionality, since the increase in accuracy and resolution allows you to measure the shape of short-term frequency instabilities at different averaging times (1 ms, 10 ms, etc.), the lack of analog nodes and blocks, the full With a digital meter performance, the high linearity of the frequency conversion characteristics is voltage or period-voltage.

Thus, the proposed transient meter allows determining the transient frequency setting function with high accuracy, as well as controlling the short-term non-stability.

bone generators, and can be used in the development and testing of controlled systems.

frequency devices

five

0

0

Claims (1)

Invention Formula A transient meter that contains the first, second, and third pulse shapers, N dividers, a switching node, a serially connected switch and adder, a serially connected synchronizer and recorder, as well as two input buses and one output bus that is connected to the synchronizer output, and the first input The bus through the first pulse shaper is connected to the first inputs of the dividers, characterized in that, in order to improve the accuracy and enhance the functionality, the sat node is introduced wasp, N RS flip-flops, N elements in AND, two elements, OR, the output of the third pulse generator is connected to the input of the reset node and the first input of the switching node, the second input of which is connected to the output of the first pulse generator, each of the N outputs of the node reset is connected to the second input of the corresponding divider and to the first input of the corresponding RS flip-flop, the second input of each RS flip-flop is connected to the output of the corresponding delimiter, the first inputs of the AND elements are connected to the outputs of the corresponding RS-flip-flop and the corresponding input I will give the second element OR, the output of which through the second pulse shaper is connected to the first input of the switch, the outputs of the elements AND are connected to the corresponding input of the first element OR, the output of which is connected to the second input of the switch, output 5 the adder is connected to the second input of the recorder, the second input bus is connected to the input of the third pulse generator, the output of the switching unit is connected to the second inputs of the element I. five 0 fut. 2 2ltix I I I I I Mi I I I t I I well -fc Jl I-j U M9Uf t I I and M I I I M i I 2S TS T w I-1 M ,,.-.- f I - /five -L-lfl u-f g; | m Mix a short / eemenous slowing frequency S FIG. B