SU1541534A1 - Device for measuring statistic parameters of crystal vibrators - Google Patents

Abstract

The invention relates to instrumentation engineering and can be used to measure the static parameters of quartz resonators. The purpose of the invention is to increase measurement speed by eliminating the time for reconfiguring the transfer coefficient of a scale converter when changing the measurement ranges of the parameters of a quartz resonator - by introducing new functional connections, as well as choosing the time of arrival of the sync pulse to the control input of the second meter of instantaneous voltage values ₂ equal to 2T ₁ + ΔT _cf , where T ₁ is the time instant of arrival of the sync pulse to the control input of the first meter of instantaneous voltage values. As a result, the transfer coefficient of the scaling converter (K _MP = 2) is not required when switching from one measurement range of the measured parameters of the crystal to another, which greatly simplifies the setup of the device. 2 Il.

Description

This invention relates to an instrumentation technique and can be used to measure the static parameters of quartz resonators, namely, static capacitance and insulation resistance.

The purpose of the invention is to increase the measurement speed by eliminating the time for reconfiguration of the transfer coefficient of the scaler when changing the measurement ranges of the parameters of the quartz resonator.

Fig. 1 shows a functional diagram of the device; Fig. 2 shows a complete equivalent circuit for replacing a quartz resonator.

The device contains a synchronization unit 1, a reference voltage source 2, a terminal 3 for connecting a quartz resonator, an operational amplifier k, a reference capacitor 5 (Co), the first 6 and second 7 instantaneous voltage meters, a scaling converter 8, the first 9 and the second 10 blocks subtraction, comparator 11.

The output of the source of the reference voltage (ION) is connected to one of the terminals 3 for connecting a quartz resonance

four

cl

with

four.

torus (CR), another terminal for connecting the RC is connected to the inverting input of the operational amplifier (op-amp) 4, the negative capacitor circuit of which includes the reference capacitor 5 (C0), the non-inverting op-amp input is connected to the common bus of the device, and the output of the op-amp - with the inputs of the first meter 6 instantaneous voltage outputs (IMZN1), the second meter 7 instantaneous voltage values (IMZN2) and the first input of the second subtraction unit 10 (BV2), while the second input of the second reading unit 10 is connected to the output of the first block 9 subtraction (BV1), and in The output is from the second input of the comparator 11, the first input of which is connected to the output of the source 2 of the reference voltage.

The output of the first meter 6 instantaneous voltage values is connected via a scaling converter 8 to the first input of the first subtraction unit 9, the second input of which is connected to the output of the second meter 7 instantaneous voltage values. Pep

. Q 5

five

0

The output of the synchronization unit 1 is connected to the synchronization input of the source 2 of the reference voltage, the second output is connected to the synchronization input of the first meter 6 instantaneous voltage values, the third output is connected to the synchronization input of the second meter 7 instantaneous voltage values.

The device works as follows.

The synchronization unit 1 generates sync pulses that control the operation of the source 2 of the reference voltage. At the output of the latter, a sequence of unipolar rectangular pulses of amplitude U "is input through a quartz resonator connected to the terminals, to the input of the operational amplifier +, to the negative, reverse circuit the connection of which includes a reference capacitor 5 with a capacity of C0,

Output voltage PU depending on the ratio of equivalent parameters of the RC is described by one of the expressions

Ґ4

oh (oh

J

with o 3-ot (1

9) 1 + WS +

JGOCoRu3

- sin (wt io, w

  a2

+ Cost + Uot C0C0RU3

 fec, - ,, + aL) + UsCiL + hz

with o - a2

UaS, G e; njv 1 + U2t C0 - n - m mn -1

at u a2

with cjj a2

where is os

R "

2L,

GO

i

U) 2 6

. oo

arctg -;

d

-n -a + -j

a2 -U) |;

- - 4a2 - 00J. L, C, are the dynamic parameters of a quartz resonator (Fig. 2); CST is the static capacitance of a quartz resonator,

9) 1 + WS +

JGOCoRu3

40

five

0

Ru is the insulation resistance of the quartz resonator; C0 - reference capacity

a capacitor; UQ is the amplitude of the output voltage of source 2.

The first meter 6 instantaneous voltage values with respect to the AtCM clock signal input to the synchronization input at time t records the output voltage Uu4 (t) at time t {+ ftt

-cm

five

equal to UVJHJK, (t + DSSc.).

The second meter 7 instantaneous values of the voltage on the sync signal with a duration of fltclt received at the synchronization input at the moment of time

t, j 2t1 + uttw fixes the output voltage UQlJ (t) at time 2t + & tcu + fitcu 2 (t, + btcu), equal to UUM5Hl (2t +.).

With all the processes, descriptions3

values of exponential function can be considered completed, since

when t is exponential

It assumes a value of 99.3% of the steady state. Thus, by choosing, -,

those. fulfilling the transient end condition, we obtain an expression for the voltages at the outputs of the instantaneous voltage meters

ui 3n (t + utcu) +

L.Q

UoC U0 (, 4. Co C0R,

.ol-c,

U

IM4NO

(2t, + 2fitCH) 2ft- +

With

+ y ° Јi + y2l2ti + 2utci;)

CQCoRuj

The voltage from the output of the meter 6 through the scaling converter 8 is fed to the first input of the first subtraction unit 9, to the other input of which the voltage comes from the output of the meter J. The output voltage of the first subtraction unit 9 is described by the expression

  KurlUuN-bHI - UUHJHJ,

where Kmp 2 - transfer ratio

scaling converter. Consequently,

U

 2uim UuMaHi

With

BV1

UoC,

f with,

Thus, the output voltage and & in (proportional to the value of the static capacitance of the quartz resonator.

The voltage from the output of the first subtraction unit 9 is fed to one of the inputs of the second subtraction unit 10, to the other input of which voltage is supplied from the output of the operational amplifier A. The output voltage of the second subtraction unit 10 is U b & g UBB Uoy

15346

The voltage from the output of the second block 10 subtraction goes to one of the inputs of the comparator 11, to the other input of which the voltage goes from the output of the source 2 of the reference voltage, while at the output of the comparator 11 pulses are generated, the duration fltn of which is determined from

Uc

and

561

Choosing the Up value in such a way that the comparator changes its state at the time instant ut tl (i.e. when all transients are finished, they get

and - PP

U0r p

WKMj

of which utH $ is

ut us out

Thus, the device measures the static parameters of a quartz resonator. In this case, the measurement error of the static capacitance of the quartz resonator in the proposed

This device is the same as the known one and can be found from the expression

I

thirty

uUcT - UbE, - UuH3n (t) where UHHaH (t, §f.

 Ye-si

The relative error in measuring the static capacitance of a quartz resonator in the device is determined from the expression

§ „-fiHuL- t 00% i- 100%.

U M3NH (t) T

0

Static measurement error

five

the capacitance of the quartz resonator in the proposed device, as well as in the known, depends only on the ratio of the dynamic and static capacitances of the quartz resonator and is not equivalent to the moment of fixing the output voltage of the operational amplifier and other equivalent parameters of the quartz resonator.

The C, / Cst ratio is the value, ® inverse to the frequency coefficient r, the value of which for various types of quartz cutoffs is in the range of 130– 2500, i.e.

3 "-.100% sO, 0 ... 0.77%

LCT r

At the same time, the proposed device is simplified in comparison with the known one due to the introduction of new functions.

connections and timing of the arrival of the sync pulse to the control input of the meter 7 t, equal to 2t (+ utc.t). As a result, the transfer coefficient of the scaling converter 8 is not required to change when switching from one measurement range of the quartz parameters

resonator. The transfer coefficient is equal to the first input of the first block.

The stacking converter is equal to two and remains unchanged when changing the measurement ranges of the parameters of the quartz resonator. This greatly simplifies the setup of the device and eliminates the loss of time to reconfigure it. When switching from one parameter measurement range to another.

15

A subtracting, the second input of which is connected to the output of the second subtraction unit, and the output to the second input of the comparator, while the first input of the second subtraction unit is connected to the output of the second meter of instantaneous voltage values, the first output of the synchronization unit is connected the second output is with the synchronization input of the first instantaneous voltage meter, the third output is with the synchronization input of the second instantaneous voltage meter, characterized in that ysheni operating speed measurement, a first output meter instantaneous values of voltage through a scaling-preobrazoFormul invention

A device for measuring the static parameters of quartz resonators, containing a source of voltage, the output of which is connected to the first terminal for connecting the quartz resonator and the first input of the comparator, the second terminal for the connector 30 is connected to the second input of the quartz resonator connected to the subtractor.

-in "-hCn- ::

with the inverting input of the operational amplifier, the negative feedback circuit of which is included. a reference capacitor, the non-inverting input of the operational amplifier is connected to the common bus of the device, and the output - to the inputs of the first and second instantaneous value meters

0

five

A subtracting, the second input of which is connected to the output of the second subtraction unit, and the output to the second input of the comparator, while the first input of the second subtraction unit is connected to the output of the second meter of instantaneous voltage values, the first output of the synchronization unit is connected the second output is with the synchronization input of the first instantaneous voltage meter, the third output is with the synchronization input of the second instantaneous voltage meter, characterized in that ysheni operating speed measurement, a first output meter instantaneous values of voltage across the converter is connected to a scaling sec

subtraction block.

Wcr

c

ti

1

if

ci jl

fig.i

Claims (1)

Claim A device for measuring the static parameters of quartz resonators, containing a reference voltage source, the output of which is connected to the first terminal for connecting the quartz resonator and the first input of the comparator, a second terminal for connecting a quartz resonator connected to the inverting input of the operational amplifier, into the negative feedback circuit of which the reference capacitor is turned on, and the non-inverting input of the operational amplifier is connected to the common bus of the device, and the output is connected to the inputs of the first and second and measurer instantaneous voltage and the first input of the first subtractor, a second input coupled to an output of the second subtracter, and an output - to a second input of the comparator, the first input of the second. the subtraction unit is connected to the output of the second instantaneous voltage value meter, the first output of the synchronization unit is connected to the synchronization input of the reference voltage source, the second output is connected to the synchronization input of the first instantaneous voltage value meter, the third output is the synchronization input of the second instantaneous voltage value meter, characterized in that, in order to improve the measurement performance, the output of the first meter of instantaneous voltage values through a scaling converter is connected to a second input of the second subtractor. Figure 1 15 * 1.534