RU1775U1 - DEVICE FOR THERMAL COMPENSATION OF THE INSTABILITY OF FREQUENCY OF QUARTZ RESONATORS - Google Patents

Abstract

DEVICE FOR THERMAL COMPENSATION OF THE INSTABILITY OF FREQUENCY OF QUARTZ RESONATORS, containing a quartz resonator, a capacitor and a thermistor, the first output of the quartz resonator is connected to the first output of the capacitor, the second output of the capacitor is connected to the first output of the thermistor, characterized in that the additional output is connected to the capacitor the second terminal of the thermistor, and the second with the first terminal of the quartz resonator.

Description

iCTPOHCTBU Yes THERMAL UNDERSTANDING QUARTZ PE3UHATUPUB

The proposed utility model relates to radio engineering and can be used to increase the temperature stability of the frequency of quartz resonators and generators.

Known devices for compensating for frequency instability

quartz resonators and generators in the temperature range using a varicap and a temperature-dependent potentiometer, for example, described by B

book of GB Altshuller Quartz frequency stabilization, m., Communication, 1974.

Such devices can significantly increase the temperature stability of the frequency of quartz resonators and, accordingly, generators, while the quartz resonator’s topological value changes little and, therefore, the fixing ability of the quartz resonator changes little.

However, it is necessary to stabilize the reference voltage with great accuracy, which increases the size and energy consumption. In addition, in order to obtain the frequency control limits necessary for thermal compensation, the reference voltage supplied to the thermopotentiometer cannot be small (the reference voltage must be at least 3-5 V),

To create a device to compensate for frequency drift in the temperature range without using a voltage stabilizer and at low voltage power supplies, you can use XR circuits, usually connected in series with a quartz resonator.

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taken as a prototype,

Figure 1 presents a diagram of a prototype device in which a capacitor Cj- is used as the reactance X.

The following notation is introduced in FIG.

1- quartz resonator;

2- capacitor;

3- thermistor.

The prototype device contains a quartz resonator 1, the first output of which is connected to a common point of the capacitor 2 and the thermistor 3, the second conclusions of which are also interconnected,

This circuit is designed for thermal condensation of a quartz resonator with a positive temperature coefficient of frequency.

The device according to the scheme of FIG. 1 works as follows:

With increasing temperature, the resistance of the thermistor will decrease, which leads to a decrease in the equivalent reactance XR of the chain, and, consequently, to a decrease in the operating frequency of the quartz resonator and generator. Thus, the total frequency drift in the temperature range of the quartz resonator, taking into account the action of the QW chain, decreases. Similarly, the overall change in the frequency of the quartz resonator and the XR chain will decrease with decreasing frequency.

The disadvantage of such a device for thermal compensation of the frequency is the introduction of large losses in the oscillatory circuit of the generator and, as a result, a decrease in the quality factor and fixing ability, a decrease in the frequency stability, margin of excitation and the output voltage of the generator,

Actual insertion loss can be defined as

if

The specified disadvantage is eliminated as follows. An apparatus containing a quartz resonator, the first output of which is connected to the first output of the capacitor, the second output of the capacitor is connected to the first output of the thermistor, an additional capacitor is introduced, the first output of which is connected to the second output of the thermistor, and the second to the first output of the quartz resonator.

Significantly reduce the insertion loss by applying the scheme of Fig., Which uses the XKS chain.

This diagram indicates:

1 - quartz resonator;

Z is the capacitor;

3- ter1; 0 resistor;

4- additional capacitor.

The device contains a quartz resonator I with a series-connected capacitor 2, in parallel with which is connected a series connection of a thermistor 3 and an additional capacitor 4, with a reactive resistance Xfl.

The proposed device operates as follows.

With increasing temperature, the resistance of the thermistor will decrease, which leads to a decrease in the operating frequency of the quartz resonator and generator. Thus, the total frequency drift in the temperature range of the quartz resonator, taking into account the action of the XXR chain, decreases. Similarly, the overall change in the frequency of the quartz resonator and the XXR chain will decrease with decreasing frequency.

In this case, the introduced losses Afew will be equal to:

Coefficient of reduction of insertion loss l /. FROM /

/

For example, with A and the ratio - the coefficient of attenuation of the external loss Dxlx will be more than 60 times, and with. and - --M B will be more than 220 times.

Therefore, the scheme of the proposed thermal compensation device using the XAR chain, allowing you to work without a voltage stabilizer and at low voltage of the voltage source and does not lead to a significant increase in losses, and, therefore, without a significant decrease in the quality factor, the margin of excitation of the generator and the output voltage.

Given the foregoing, the authors believe that the proposed device meets the requirements for a utility model.

Patent holder - Voronezh Research Institute of Sayazi.

Deputy Chief Engineer S - Yu.V. Snezhno

Claims (1)

DEVICE FOR THERMAL COMPENSATION OF THE INSTABILITY OF FREQUENCY OF QUARTZ RESONATORS, containing a quartz resonator, a capacitor and a thermistor, the first output of the quartz resonator is connected to the first output of the capacitor, the second output of the capacitor is connected to the first output of the thermistor, characterized in that the additional output is connected to the capacitor the second terminal of the thermistor, and the second with the first terminal of the quartz resonator.