JPH04157922A - Digital control type temperature compensation piezoelectric oscillator - Google Patents

Abstract

PURPOSE:To suppress a sudden phase change in a time required for satellite communication by interrupting temperature compensation tentatively based on a temperature data or predicting the temperature data in a digital control type temperature compensation piezoelectric oscillator. CONSTITUTION:The output digital code of a temperature detection circuit 1 is fed to a function generating circuit 2 through a control circuit 5. When a control input is at a high level, temperature compensation is implemented and when the control input is at a low level, a temperature data is stored. Thus, the temperature compensation is stopped tentatively. Moreover, as other embodiment, a control circuit 8, an arithmetic storage circuit 9 and a memory circuit 7 are added, a temperature is predicted by a high-degree approximation equation, and the temperature compensation is implemented by the predictive data. Consequently a period when the constant temperature is predicted is utilized. Satellite communication is implemented for the period.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a piezoelectric oscillator, and in particular to a digitally controlled temperature-compensated piezoelectric oscillator that suppresses sudden phase changes within a required time, which is a problem in satellite communications, etc. (hereinafter referred to as DTCXO).

[Conventional technology]

As shown in Figure 9, a conventional DTCXO includes a circuit (hereinafter referred to as a temperature detection circuit) 1 that converts temperature into a digital value, a function generation circuit 2, and a circuit that converts the digital value into an analog voltage (hereinafter referred to as a DAA converter). ) 3 and a voltage controlled piezoelectric oscillator (hereinafter referred to as VCXO) 4.

With such a configuration, as shown in the characteristic diagram of FIG. 10, a stable frequency-temperature characteristic B is realized by compensating for the frequency-temperature characteristic with many frequency fluctuations.

In FIG. 9, the ambient temperature of the piezoelectric oscillator is detected by a temperature detection circuit 1 including a thermistor, etc., and a function generation circuit 2 outputs a digital code for compensating the frequency-temperature characteristics of the piezoelectric oscillator. The digital code output from the function generating circuit 2 is converted into an analog voltage by the D/A converter 3, and is supplied to the ■CX○4, which outputs a predetermined oscillation frequency.

FIG. 11 is another block diagram of the conventional example, in which the function generation circuit 2
In this example, a memory circuit 7 is used instead of a memory circuit 7. The memory circuit 7 outputs a digital code for compensating the frequency-temperature characteristics of the piezoelectric oscillator, and the digital code output from the memory circuit 2 is converted into a voltage by the D/A converter 3 and supplied to the VCXO 4.

[Invention or problem to be solved]

The conventional DTCXO described above performs a temperature compensation operation when a temperature change is detected, so it has the disadvantage that a sudden phase change occurs within a certain time Δt as shown in the timing diagram of FIG. 12. Satellite communication systems where the Doppler effect is a problem cannot be used.

The purpose of the present invention is to solve these problems and to provide a digital control type that suppresses sudden phase fluctuations by temporarily stopping the temperature compensation operation for a certain period of time using an external control signal, and by performing temperature compensation. The purpose is to provide temperature compensation.

[Means to solve the problem]

The configuration of the DTCXO of the present invention includes a temperature detection circuit that converts and outputs temperature into a digital value, a function generation circuit that outputs a digital code that compensates for the frequency value-temperature characteristics based on the output of this temperature detection circuit, and this function generation circuit. a DA converter circuit that converts the output digital value of the circuit into an analog voltage;
In the digitally controlled temperature compensated piezoelectric oscillator including a controlled piezoelectric oscillator that oscillates based on the DAA converter output voltage, between the temperature detection circuit and the function generation circuit,
Alternatively, a control circuit or a holding circuit is connected between the function generation circuit and the DA converter circuit to temporarily stop the temperature compensation operation based on an external signal.

Another configuration of the DCXO of the present invention includes a temperature detection circuit that converts temperature into a digital value, a memory circuit that outputs a digital code that compensates for frequency-temperature characteristics using the output of this temperature detection circuit, and an output digital value of this memory circuit. In a digitally controlled temperature-compensated piezoelectric oscillator that includes a DA converter circuit that converts a value into an analog voltage and a voltage-controlled piezoelectric oscillator that oscillates from the Noanack voltage of this DA converter circuit, there is a voltage between the temperature detection circuit and the memory circuit. , or further comprising a control circuit for temperature compensation and an arithmetic storage circuit connected to the control circuit and controlled by an external input signal between the memory circuit and the DA converter circuit. .

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, which is configured by adding a control circuit 5 to the conventional configuration.

As shown in the block diagram of FIG. 2, this control circuit 10 includes an AND circuit 1 that takes a logical AND between a data input and a control input.
1, an inverter 12, and a latch circuit 13. When the control input is at L level, input temperature data is held, and when the control input is at H level, temperature compensation operation is performed.

According to this embodiment, the output digital code of the temperature detection circuit 1 is supplied to the function generation circuit 2 through the control circuit 5. Therefore, when the control input is set to 1, the normal temperature compensation operation is performed, and when the control input is set to L level, the temperature data is held. Therefore, the temperature compensation operation can be temporarily stopped, and communication with the satellite can be performed during this temporary stop, thereby preventing sudden phase fluctuations.

FIG. 3 is a block diagram of a second embodiment of the present invention, in which the control circuit 5 of FIG. 2 is connected between the output terminal of the function generation circuit 2 and the D/A converter 3. In this case too,
The operation is similar to that shown in Fig. 1.

FIG. 4 is a block diagram of a third embodiment of the present invention, which is constructed by adding a holding circuit 6 such as a sample and hold circuit to the conventional structure. According to this embodiment, the temperature sensor 1
is supplied to the function generating circuit 2 through the holding circuit 6. Normally, the data changes when a temperature change is detected, and when a temperature compensation operation is performed or a control signal is input from the outside, the holding circuit 6 holds the data at that point. This data holding can hold the input data and temporarily stop the temperature compensation operation, as shown in the timing chart of FIG. Therefore, communication in the satellite communication system can be temporarily stopped. Therefore, communication in the satellite communication system can be performed during this temporary suspension time.

This embodiment can also be connected between the output end of the DA converter 3 and the input end of VCχ0, as in FIG.

In these embodiments, it is clear that if the temperature detection circuit 1 is one that outputs an analog voltage, the output AD converter may be added.

FIG. 6 is a block diagram of a fourth embodiment of the present invention, in which a control circuit 8 and an arithmetic storage circuit 9 having external input terminals are replaced with a temperature detection circuit 1 and a memory circuit 2. It is configured by adding it between.

According to this embodiment, the output digital code of the temperature detection circuit 1 is inputted to the arithmetic storage circuit 6 through the control circuit 5, and
As shown in the figure, calculation processing is performed from data C using a high-order approximation formula. Future temperature data D after Δt2 is predicted. When a signal is applied to the input terminal from the outside, a temperature compensation operation is performed based on this predicted temperature data.

In this case, in the communication of the satellite communication system, Δt in FIG.
It should be done between 2.

FIG. 8 is a block diagram of a fifth embodiment of the present invention, in which a control circuit 8 is connected between the output terminal of the memory circuit 7 and the input terminal of the D/A converter 3, and the control circuit is connected to the control circuit from the outside. The input/output terminals of an arithmetic storage circuit 9 having input terminals are connected.

In this example, since the compensation data itself can be handled,
This has the advantage of allowing finer control. Note that a microcomputer circuit can also be used as the arithmetic storage circuit.

〔Effect of the invention〕

As explained above, the present invention can temporarily stop the temperature compensation operation of the DTCXO and predict temperature data, so it has the effect of not causing sudden phase changes within the required time in satellite communications etc. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a circuit diagram of the control circuit 5 shown in FIG. 1, and FIGS. 3 and 4 show second and third embodiments of the present invention. FIG. 5 is a timing diagram explaining the operation of FIG. 4, FIG. 6 and FIG. 8 are block diagrams of the fourth and fifth embodiments of the present invention, and FIG. 7 is a timing diagram explaining the operation of FIG. Timing diagrams explaining the operation, Fig. 9, Fig. 1
Figure 1 is a block diagram of the second side of a conventional digitally controlled temperature-compensated piezoelectric oscillator, Figure 10 is a characteristic diagram showing the change in frequency fluctuation due to temperature in Figure 9, and Figure 12 explains the phase fluctuation of the conventional example. FIG. 1...Temperature detection circuit that converts temperature into a digital value, 2
... Function generation circuit, 3. DA converter, 4. Voltage controlled piezoelectric oscillator, 5, 8.. Control circuit, 6.. Holding circuit, 7.. Memory circuit, 9.. Arithmetic storage circuit, 11.・
...AND circuit, 12...inverter, 13...latch circuit.

Claims (1)

[Claims] 1. A temperature detection circuit that converts and outputs temperature into a digital value, a function generation circuit that outputs a digital code that compensates for frequency value-temperature characteristics using the output of this temperature detection circuit, and this function generation circuit. A digitally controlled temperature-compensated piezoelectric oscillator including a DA converter circuit that converts an output digital value of a circuit into an analog voltage, and a controlled piezoelectric oscillator that oscillates using the output voltage of the DA converter, the temperature detection circuit and the function generation circuit. A digitally controlled temperature compensated piezoelectric oscillator, characterized in that a control circuit or a holding circuit is connected between the function generating circuit and the DA converter circuit, or between the function generating circuit and the DA converter circuit. 2. A temperature detection circuit that converts temperature into a digital value, a memory circuit that outputs a digital code that compensates for frequency-temperature characteristics using the output of this temperature detection circuit, and a DA that converts the output digital value of this memory circuit into an analog voltage. In a digitally controlled temperature-compensated piezoelectric oscillator including a converter circuit and a voltage-controlled piezoelectric oscillator that oscillates using an analog voltage of the DA converter circuit, there is a connection between the temperature detection circuit and the memory circuit, or between the memory circuit and the D
A digitally controlled temperature-compensated piezoelectric oscillator, characterized in that it is provided with a control circuit for temperature compensation and an arithmetic storage circuit connected to the control circuit and controlled by an external input signal, between the A converter circuit and the A converter circuit. .