JPS59205803A - Piezoelectric oscillator with thermostatic oven - Google Patents

Abstract

PURPOSE:To improve the performance in frequency change against temperature change by inserting a heat-sensitive element between the connections of an output of an amplifier section of a piezoelectric oscillator and a feedback section. CONSTITUTION:A piezoelectric oscillator 2 is accommodated in the inside of a temperature insulating section 1 of a thermostatic oven to decrease the temperature change as less as possible. The heat-sensitive element, e.g., a parallel circuit comprising a thermister 17 and a resistor 18 is inserted between the connections of an output of the amplifier section and a feedback section. When a forward voltage drop of diodes 15, 16 is changed by +DELTAVF because of temperature change, the resistance value of the thermister 17 is changed by +DELTARTH and the combined resistance value of the thermister 17 and the resistor 18 is changed by +DELTAR. In setting the amount of change +DELTAR to a value to cancel the +DELTAVF, the current value fed back to a piezoelectric vibrator 2 is not changed against temperature change. As a result, the exciting level of the piezoelectric vibrator 2 is kept constant.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermostatic oven-equipped piezoelectric oscillator in which a piezoelectric oscillator is housed in a heat-retaining section of the thermostatic oven.

<Prior Art> In order to ensure that the number of oscillation stations of a conventional piezoelectric oscillator changes rapidly with changes in ambient temperature, a method is generally used in which a piezoelectric oscillator is housed in a heat-retaining section of a thermostatic oven. The element in the piezoelectric oscillator that has the greatest influence on temperature changes is the piezoelectric vibrator. Therefore, if this piezoelectric vibrator is housed in a constant temperature bath where temperature changes are small, the stability of oscillation frequency changes with respect to temperature changes can be increased.

FIG. 1 shows an example of the circuit configuration of a conventional piezoelectric oscillator with a constant temperature oven. Here, 1 is a heat-retaining part of a thermostatic oven, 2 is a piezoelectric vibrator held in the thermostatic oven 1, 3 to 8 are capacitors, 9 to 13 are resistors, 14 is a transistor, and 15.16 is a diode. . In this circuit configuration, a circuit including resistors 9 to 12, capacitor 5, and transistor 14 is an amplifier section,
The diodes 15, 16 and the capacitor 6 constitute an amplitude limiting circuit, and the circuit including the capacitors 3, 4, and 8, the resistor 13, and the piezoelectric vibrator 2 is a feedback section.

The piezoelectric vibrator 2 of the feedback section is housed in the heat-retaining section 1 of the thermostatic chamber, and by minimizing the temperature changes that the piezoelectric vibrator 2 undergoes due to changes in ambient temperature, the frequency as a piezoelectric oscillator responds to temperature changes. Improves change performance (stability).

However, since the other elements are located outside the thermostatic chamber 1, they undergo temperature changes that are almost the same as those experienced by the piezoelectric oscillator, and the effect of frequency changes on performance is not small. Among these, changes in the forward voltage drop due to temperature changes in the diodes 15 and 16 change the excitation level of the piezoelectric vibrator 2, which is one of the obstacles to improving frequency change performance. FIG. 2 shows an example of the excitation level characteristics of the piezoelectric vibrator 2 with respect to changes in the forward voltage drop of the diodes 15 and 16 in FIG. 1, and FIG. 3 shows an example of frequency characteristics with respect to changes in ambient temperature in FIG. 1.

In order to improve this drawback, the piezoelectric oscillator as a whole is housed in the heat-retaining section 1 of a thermostatic oven, as shown in Fig. 4, but the structure is complicated, the shape is large, and the power consumption of the thermostatic oven increases. However, it had the disadvantage of being expensive.

<Objective of the Invention> The object of the present invention is to eliminate the drawbacks of the conventional thermostatic chambered piezoelectric oscillator mentioned above, and to create a constant temperature oscillator that has high frequency change performance with respect to temperature changes, has a simple structure, is small in size, has low power consumption, and is inexpensive. An object of the present invention is to provide a piezoelectric oscillator with a tank.

<Summary of the Invention> The circuit configuration of the oven-controlled piezoelectric oscillator of the present invention includes an amplifier section having an amplitude limiting circuit at its output, a feedback section including at least a piezoelectric vibrator and a phase inverting capacitor, and the piezoelectric vibrator internally. The device is characterized in that a thermostatic chamber to be accommodated is changed, and a temperature sensing element is inserted between the connection between the output of the amplification section and the feedback section.

According to the circuit configuration of the present invention, the excitation level of the piezoelectric vibrator can be adjusted by canceling the change in the forward voltage drop due to the temperature change of the diode of the amplitude limiting circuit in the amplifier output by the change in the inserted temperature sensing element. The frequency can be kept constant, and the performance of the frequency change with respect to the 2:+'+i degree change of the piezoelectric oscillator in the constant temperature oven can be further improved. Since only the piezoelectric vibrator is required as the element housed in the heat-retaining part of the thermostatic oven, it is possible to provide an inexpensive piezoelectric oscillator with a thermostatic oven, which has a simple structure, a small shape, and low power consumption of the thermostatic oven. That's it.

<Example> This invention will be described in more detail with reference to the drawings. FIG. 5 is a circuit diagram showing an embodiment of the circuit configuration of the thermostatic oven-equipped piezoelectric oscillator according to the present invention.

In the figure, a piezoelectric vibrator 2 is housed inside a heat-retaining part 1 of a thermostatic oven to minimize temperature changes. Resistors 9 to 12, mandensor 51. Torrensista 1, 4
, -, diodes 1 '5, '16, and an amplitude limiting circuit 21 constituted by a capacitor 6. The amplifier section 22 includes capacitors 3, 4, and 8, a resistor 13, and a piezoelectric vibrator 2. The circuit is the feedback section 23. Capacitor 3.4 is a phase phase 1111, capacitor.

In this embodiment, a parallel circuit of a temperature sensing element, such as a thermistor (registered trademark) 17, and a resistor 18 is inserted between the output of the amplifier section and the feedback section. Is it good now? A 1 degree change increases the forward voltage drop of diode 15 and 16 by +△
(2) If F changes, the resistance value of the thermistor 17 changes to +RTH at the same time, and the combined resistance value of the thermistor 17 and resistor 18 also changes by +ΔR.

Here, if the change meter 17 for →- is set to a value that cancels +△vF, the current value fed back to the piezoelectric vibrator 2 will not change with temperature change ≦ As a result, the piezoelectric range will change. The excitation level of child 2 is kept constant.

FIG. 6 shows an example of the excitation level characteristics of the piezoelectric vibrator with respect to ambient temperature changes of the constant temperature oven piezoelectric oscillator shown in FIG. 5, and FIG.

Examples of frequency characteristics of the vibrator with respect to changes in ambient temperature are shown below.

<Effects> As explained above, according to the present invention, in order to improve the frequency change performance of the oven-equipped piezoelectric oscillator with respect to temperature changes, only the piezoelectric vibrator is required as the element housed in the heat-retaining section of the oven. Therefore, it is possible to provide an inexpensive piezoelectric oscillator with a thermostatic oven, which has a structure of 1r, +1r, ii, is small in size, and has low power consumption in the thermostatic oven.

Incidentally, FIG. 5 shows one embodiment, and a circuit whose impedance changes depending on temperature may be constructed using a diode or the like.

ll ffi'+r-+l explanation of the drawings Figure 1 is a circuit diagram showing an example of the circuit configuration of a conventional piezoelectric oscillator with a constant temperature oven.
Figure 2 is a graph showing an example of the excitation level characteristics of a piezoelectric vibrator with respect to temperature changes in the forward voltage of the diodes 15 and 16 in Figure 1, and Figure 3 is a graph showing an example of frequency characteristics with respect to ambient temperature changes in Figure 2. 4 is a circuit diagram showing an example of the circuit configuration of a conventional piezoelectric oscillator with a thermostatic oven, FIG. 5 is a circuit diagram showing an example of the circuit configuration of a piezoelectric oscillator with a thermostatic oven according to the present invention, and FIG. Perimeter t″1□1 in Fig. 5
FIG. 7 is a graph showing an example of the excitation level characteristic of a piezoelectric vibrator with respect to a change in V degree. FIG.

1: Holder of constant 2 flli tank 2: rt part, 2: Piezoelectric gland oscillation,
3: Phase rotation capacitor, 4: Phase rotation capacitor, 5
~8: Capacitor, 9~13, 18: Resistor, 14: Transistor, 17: Thermistor as a temperature sensing element, 21
: amplitude limiting circuit, 22: amplification iτIS, 23: feedback section.

Patent applicant: NEC Corporation Representative Kurumao Kusano 1
Figure 72 Figure 1'l# → Den/i 已 3 Figure 4 Flash

Claims (1)

[Claims] (1) A thermostatic oven-equipped piezoelectric oscillator comprising an amplifier section having an amplitude limiting circuit at its output, a feedback section including at least a piezoelectric vibrator and a phase inverting capacitor, and a thermostatic oven housing the piezoelectric vibrator therein, A temperature sensing element whose impedance changes depending on the temperature is inserted between the output side of the amplification section and the feedback section, and a change in the excitation voltage for the piezoelectric vibrator due to a change in the oscillation output due to temperature fluctuation is inserted. A piezoelectric oscillator with a constant temperature oven, characterized in that the temperature is canceled by changes in the impedance of a temperature sensing element.