SU747293A1 - Laser Angle Acceleration Sensor - Google Patents

Description

The invention relates to the technique of piezoquartz production and can be used to measure the parameters of piezoquartz resonators at various stages of its manufacture. A device for measuring the parameters of quartz resonators, which contains in series, is known. connected high-frequency generator, measuring quadrupole with the quartz resonator under investigation, high-frequency amplifier, high-frequency detector, op, phase detector and integrator, as well as a modulation generator, a selective amplifier, a detector and an attenuator 1. The disadvantage of it is to carry out measurements only in a narrow frequency band not exceeding the frequency band of a quartz resonator.

Also known meter frequency dynamic parameters of quartz resonators, which contains a series-connected tunable oscillator with a frequency meter, a quadrupole with a quartz resonator, an amplitude detector, amplifier and indicator, as well as series-connected comparator, trigger and integrator 2. -

The disadvantage of it is a significant measurement error in the dynamic range of measurement parameters of quartz resonators.

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

The goal is achieved by changing. dynamic parameters quartz resonator containing a tunable oscillator with a frequency meter, a quadruple circuit with a quartz resonator under study, an amplitude detector, an amplifier and an indicator, and a successively connected comparator, trigger and integrator, output connected to the control input of the tunable oscillator with a frequency meter , period 20 analog converter, amplitude values converter, two diodes, second comparator, second trigger and two resistors elitel voltage, the output of the amplifier is connected to one

25 of the amplitude values of the transducer inputs, directly and through a diode connected in the forward direction - with another input of the above transducer and through a diode, 30 included in the opposite direction. With the third input of the amplitude conversion transform, the output of which is connected to one from the inputs of the first and second comparators, the other input of the first of which is connected to one of the terminals of the first resistor of the voltage divider connected to the control: the equalizer input of the integrator and with the output of the period-analog converter which o is connected to the output of the first trigger, connected to the output of the second trigger, the first input of which is connected to the output of the first comparator, and its second input is connected to the output of the second comparator, the second input of the voltage divider connected to the other output and the second a voltage divider resistor, the other output of which is connected to the device core. FIG. 1 shows a structural diagram of the meter; in FIG. 2 shows the amplitude-frequency characteristics (AFC) of a quartz resonator with a small (1) and large (2) dynamic equivalent resistance; in FIG. 3 the frequency response of a quartz resonator with a small (1) and a large (2) dynamic equivalent resistance; converted in the meter, in FIG. 4 - signal plots at various points of the meter. The block diagram of the meter contains a transducer FII generator with a frequency meter 1, measuring four poles, with a quartz resonator 2 amplitude detector 3, amplifier 4, two-channel converter 5 amplitude values, diodes b and 7, comparator 8, second comparator 9, triggers 10 and 11, integrator 12, period-analog converter 13, two voltage divider resistors 14 and indicator 15. The measurement error of the parameters of the quartz resonator is determined by the accuracy of integrating the frequency modulated method with an electronic frequency meter. . The maximum measurement error in this case can be determined from the expression: dJ -. (MV (4VT M where V is the generator frequency tuning rate in relative units, T is the counting frequency of the frequency amp & f / f - generator frequency deviation. Inequality shows that in order to reduce the measurement error, it is necessary to increase the generator frequency tuning rate and the frequency counter counting time, however, it is impossible to increase these parameters without limit, since the maximum value of the generator tuning rate is limited to goodness The quartz resonator frequency and measurement parameters of the quadrupole, and the frequency counter counting time is limited by the measurement performance and the frequency drift component of the quartz resonator. The minimum deviation value is limited by the parasitic frequency modulation of the oscillator frequency. - due to the dynamic expansion of the LCH of a quartz crystal. About a resonator, i.e., its various parama values moat equivalent resistance and quality factor. 1, it is IMPORTANT; when dynamically expanding the frequency response of a quartz resonator, the frequency measurement is performed with an error caused by comparing the signal with the allowed threshold level selected from the condition: UQ Osh, where UACH is the release threshold; threshold; Um - the noise level due to the parasitic frequency module. generator at the input of the threshold element. For a quartz resonator with a minimum dynamic resistance, it is impossible to obtain a small frequency deviation at a selected threshold level for a quartz resonator with a minimum dynamic resistance. The width of the frequency response in terms of the threshold is related to the following relation with the maximum R.-na and minimum f min values of the measured resistance. Gh-R ryiin Kn t n Rj is the load resistance of the measuring quadripole. A bipolar amplitude converter (ESD), together with diodes 6 and 7, thus provides the G1 conversion of the frequency response shown in FIG. 1 to the form shown in FIG. To ensure such a conversion, the PAZ 5 must satisfy the following requirements; 1m: the charging time of the capacitors of both channels of the PAZ 5 must be the same, the discharge time of these capacitors must be significantly different. If the rate of increase of the signal at the converter input is constantly or little changed, and the maximum values of the signals also have a small scatter, then choosing the diodes of the capacitors and the input resistances of the differential amplifier of the converter appropriately can not be entered diode 6 and 7. However, under the conditions of the wide scatter measurement of the signal and its amplitude requires the introduction of counter-enabled diodes b and 7, since their absence leads to a significant flattening of the output signal trough. Due to their presence, the charging time of the ESD capacitors 5 is the same, then the maximum generalized frequency detuning (see figure 3) can be determined from

0.75 (ck;) i

Let us compare equalities (3) and (2), for example, with L 0.14, L 0.8, which corresponds to R 5-200 Ohms and Yashch 300 m. Then:

; .

Taking into account equality (1), we find that the measurement error after the introduction of a two-channel converter 5 with diodes 6 and 7 decreases 313 times.

"V

h

-k)

H

/ t

In the General case, the decrease in measurement error is also seen from a comparison of Fig. 1 and 3. At the output of converter 5, the extreme values of the signal coincide with each other and with zero. Therefore, the signal deviation, even with a constant response threshold and a large scatter in the dynamic resistances of quartz resonators, varies little (compare in Fig. 2 and Fig. 3).

The dynamic parameter meter of the quartz resonators works as follows (see Fig. 1 and Fig. 4).

In the initial state, at the output of the PAZ 5, there is no voltage (see Fig. 4, the voltage Ug in time tf). The modes of the comparators 8 and 9 are selected so that, in the absence of a signal at their inputs, the comparator 8 outputs the signal Ua corresponding to a logical one, and the comparator 9 produces a voltage U, corresponding to a logical zero. At the output of the trigger 10, the voltage UJQ is zero, and the voltage from the output of the trigger 11 acts on the integrator 12, the output voltage that goes to the input of the generator 1 and tunes its frequency, bringing it closer to the frequency of the quartz resonator. on the left slope of the frequency response of the measuring quadrupole 2 with a quartz resonator (Fig.2), the voltage at the output of the PAZ 5 is zero, since the constant charging times of its capacitors are equal to each other. In the moment

t the frequency of the oscillator coincides with the frequency foj of the quartz resonator with a series resonance. The constant discharge times of the PAZ 5 capacitors are significantly different.

from each other, therefore, with a subsequent increase in the generator frequency at the output of the PAZ 5, the voltage Uj- increases. At time tg, the voltage Ug from the ESD 5 output equals the trigger threshold of the comparator 8. It should be noted here that the inputs of the comparators are simultaneously affected by a signal carrying information about the frequency response of the measuring quadrupole and noise. Therefore, the output voltages U Ug of the comparators 8, E are transferred from one to zero and vice versa after issuing a series of short pulses equal to one. Thus, at time t, the comparator 8 first generates a series of short single pulses and then zero. The state of the trigger 10 does not change. At time t, the voltage Ug from the output of the PAZ 5 is equal to the threshold {} of the operation of the comparator 9, the latter gives p

single pulses. The first positive voltage drop overturns the trigger 10 f which overturns the trigger 11. As a result, the voltage from the output of the integrator 12 decreases

and tunes the frequency of oscillator 1 down. At time t, the voltage Ug at the output of the PAZ 5 is equal to the threshold UQ / J of the operation of the comparator 8. The comparator 8 outputs a series of single pulses.

and then the unit. The first positive differential trigger 10 overturns without affecting the trigger trigger 11. At time tg, the frequency of the generator 1 coincides with the frequency f of the quartz

resonator. At time t, the voltage at the output of the ESD 5 is equal to the response threshold Uj, the comparator 8. The comparator 8 outputs a series of single pulses, and then zero. The trigger 10 is not me-.

No state. At time t, the voltage Uj at the output of the PAZ 5 is equal to the response threshold UQ, the comparator 9. The comparator 9 outputs a series of single pulses. The first positive voltage drop, trigger 10, is triggered and flips trigger 11. As a result, the voltage with the output of integrator 12 begins to increase, increasing the frequency of generator 1. Then the process repeats. Converter

13, the analog period produces a voltage inversely proportional to the time interval between t and t-. Therefore, decreasing the Q factor of the crystal resonator reduces the threshold for the operation of the comparators, which leads to a decrease in the frequency deviation of the oscillator 1, and also affects the control input of the integrator integration time constant 12,

signal from the output of the converter 13

period-analogue, increases the frequency-tuning frequency. 1. Therefore, in accordance with Equation 1, the integration error of the frequency-modulated signal by the electronic frequency meter is kept small.

Thus, the converter has 5 amplitude values, diodes 6 and 7 Mainly provide high accuracy of measurements when the dynamic resistance of the quartz resonator changes, and elements 8.9, 10 and 11, 13, 14 provide high accuracy of measurements when the quality of the quartz resonator changes.

Claims (2)

1. USSR author's certificate number 437979, cl. G 01 R 27/00, 1973. 2. Authors certificate of the USSR 460510, cl. G 01 R 23/00, 1974 (prototype). Thebes 1 /four HZD-rCII} 1 (XfMff / miffama) ( oiaxSmaxjamLn