SU1182438A1 - Apparatus for measuring quality of oscillatory lc-circuit - Google Patents

Abstract

A DEVICE FOR MEASURING THE VIBILITY OF VIBRATING L C-CIRCUITS, containing a trigger pulse generator, the first driver. interval, two interval time meters and a dividing unit, characterized in that, in order to extend the measurement range in the low frequency region, a null-body second interval generator, a key and a dc generator are introduced into it, and the output of the dc generator through the key is connected to the terminal of the device for connecting the LC circuit under study and to the input of the zero-body, the output of which is connected to the inputs of the interval drivers, the start input of the second of which is connected to the output of the trigger pulse generator the control input of the key, the outputs of the first and second interval formers are connected to the corresponding inputs of the division unit through the interval duration meters, the output of which is the output of the device.

Description

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The invention relates to a measurement technique. It can be used to measure the Q-factor of inductors of low-frequency optical filters and oscillatory circuits with non-linear elements.

The purpose of the invention is to expand the range of measurements in the low frequency region.

Figure 1 shows the block diagram of the device J in figure 2 - timing diagrams, according to his work and his work.

The device contains series-connected oscillatory 1C - c6ntur 1, key 2, generator 3 of direct current, as well as a null organ 4, the output of which is connected to the inputs of two channels 5 and 6, each of which contains formors 7 and 8 of the interval connected to the meters 9 and 10 of the interval duration, the outputs of which are connected to the inputs of the dividing unit 11, the generator 12 of start pulses, the output of which is connected to the input of the driver 8, and the terminal 13 of the device for connecting the LC circuit.

The device works as follows.

Start pulse: from the output of the generator 12 opens the key 2 (Fig. 2a, b), ensuring the accumulation of electromagnetic energy in the oscillatory circuit 1 under study from the generator 3. The duration of the current flow through the oscillating circuit 1 must not be less than the time of the transition process of energy storage in order to The moment of the termination of the trigger pulse in the oscillatory circuit has established a mode.

At the end of the pulse start-up action, the key 2 is closed (fig. 2a, b, moment bo) and free damped oscillations appear at the output of the investigated oscillatory circuit. At the same time, the leading edge of the trigger pulse initiates the process of forming the interval T, t, –tQ in the driver 8 (FIG. 2d, moment ig).

The voltage U (t) on the capacitor C of circuit 1 when the switch 2 is closed is changed according to the following law:

 coscDet-QeinWct, VI)

capacitor voltage at time

damping coefficient;

06

2L LC resistance,

g

L inductance;

Ngsc

 G g - the frequency of free damped oscillations,

 p- - - measuring the quality factor, 21 2L

Ci) is the natural frequency of the CS circuit.

When the oscillation passes through the first zero value at the moment of time, T, (Fig. 26), the expression (1) vanishes and then the equality: cos CSTT

,; (2)

0 (W

While ensuring the formation of a phase shift of CO with T, within the interval, the expression (2) takes the form:

(3)

Q

CJcT,

At each transition of the free damped Kone6aHVieM through a zero value, the null organ 4 produces a short locking pulse (Fig. 2b). When the decaying oscillation reaches its first zero value (Fig. 26, time 4i), a pulse is generated at the output of the null organ 4, which completes the process of forming the interval (t -t) in the imaging unit 8 and at the same time forming the interval () in the imaging unit 7. In the duration gauge 10, the signal C is fixed, which is proportional to the interval duration (tpi-t,) from the moment of occurrence of the oscillation until it reaches the first zero value.

The next impulse from the output of the nullorgan 4 at the repeated transition by a damped oscillation through a zero value completes the formation of the interval () in the imager 7. At the same time, in the duration meter

9, the signal M is fixed, proportional to; y; the efficiency of one of the half-periods of the damped oscillation.

At the output of dividing unit 11, which forms the ratio of the received durations, a signal is reproduced that is proportional to the measured Q-factor of the oscillatory, C-loop.

which, taking into account (3), has the following mathematical expression

M TC.

tt;

Tyyg

half period of damped oscillations.

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R

fpU2.f

fie. 2

Claims (1)

A DEVICE FOR MEASURING THE QUALITY OF VIBRATION L C-CIRCUITS, comprising a trigger pulse generator, a first driver. interval, two measuring instruments for the duration of intervals and the division unit, characterized in that, in order to expand the measurement range in the low-frequency region, a zero-organ _{3 is} placed in it, a second interval former, a key and a direct current generator, while the output of the direct current generator through the key connected to the terminal of the device for connecting the LC-circuit under study and the input of the zero-organ, the output of which is connected to the inputs of the interval shapers, the start input of the second of which is connected to the output g of the start pulse generator and control -governing key input, the outputs of the first and second through slot formers meters duration intervals are connected to respective inputs divider whose output is an output device.