JPH02295223A - Automatic production method of temperature correction table for temperature compensated oscillation circuit - Google Patents

Abstract

PURPOSE:To omit the use of an equipment of a large scale by changing the temperature within a range where the characteristic of a temperature compensated oscillation circuit is assured and producing automatically the correction value at each temperature point to automatically produce a temperature correction table. CONSTITUTION:A phase comparison means 40 and a signal generating means 50 are added to a temperature compensated oscillator TCO for the formation of a phase locked loop. Then the temperature is changed within a range where the characteristic of the TCO is assured. The means 40 confirms a phase locked state every time a change detecting means 60 detects the change the minimum one unit. The value pointed by the means 50 then is equal to the wanted correction value. This correction value is written into an address designated by the temperature measurement value in a temperature correction table memory 30. Thus a temperature correction table is automatically produced. Consequently, the use of a measuring instrument and the computer system of large scales can be also omitted.

Description

[Detailed Description of the Invention] [Summary] Regarding a method for automatically creating a temperature correction table for a temperature-compensated oscillation circuit, the temperature is changed within a range that guarantees the characteristics of the temperature-compensated oscillation circuit, and the correction value is calculated at each temperature point. The purpose of the present invention is to provide a method for automatically creating a temperature correction table for a temperature controlled oscillator circuit by automatically generating a temperature correction table by automatically generating a voltage controlled oscillator, a temperature measurement means, and a temperature correction table. Phase comparison means for comparing the phase of the output clock of the voltage controlled oscillator and the reference clock, and signal generation for supplying a correction signal to the voltage controlled oscillator so that the phase comparison means is phase-locked to the temperature compensated oscillator circuit consisting of a table memory. and a change detection means for detecting that the temperature measurement means has changed by the minimum one unit of temperature measurement, the ambient temperature of the temperature compensated oscillation circuit is changed within a temperature range that guarantees the characteristics, and the change detection means Each time a minimum 1-unit change in temperature is detected, the phase comparison means confirms that the phase is locked, and the value indicated by the signal generation means at that time is specified as the temperature measurement value in the temperature correction table memory. The temperature correction table is automatically created by writing to the address specified in the table.

[Industrial application field]

The present invention relates to a method for automatically creating a temperature correction table for a temperature compensated oscillation circuit.

There are high-precision oscillators such as crystal oscillators and rubidium atomic oscillators, but among these, when particularly high precision is required, the oscillator is placed in a constant temperature oven and the temperature is kept constant. Oscillator is used.

Such a method of placing the oscillation circuit in a thermostatic oven and keeping the temperature constant requires a complicated configuration of the thermostatic oven and temperature control means for the thermostatic oven, making the oscillator expensive.

Therefore, as a method that does not use a constant temperature oven, an oscillation element,
Temperature compensated oscillators (hereinafter referred to as TCOs) are used which have a function of compensating for fluctuations in oscillation frequency due to temperature characteristics of circuit components used in oscillation circuits.

[Conventional technology]

FIG. 3 shows a block diagram illustrating a conventional example.

The conventional example shown in FIG. 3 converts correction values specified by a voltage controlled oscillator (hereinafter referred to as VCO) 10, a temperature measurement means 20, a temperature correction table memory 3OA, and a temperature correction table memory 30A from D/A. The temperature compensated oscillator circuit includes a D/A conversion circuit 34 that inputs data to the VCOIO, a frequency counter 70 for creating a temperature correction table, and a correction value input circuit 80.

With the above-described configuration, the temperature is varied within a temperature range that guarantees the characteristics, and the temperature at that time is measured by the temperature measuring means 20. on the other hand,
Since the oscillation frequency changes as the temperature changes, the oscillator frequency is counted by the frequency counter 70,
A correction value is input from the correction value input circuit 80 so that a predetermined oscillation frequency is achieved.

Further, since the control voltage of the VCOIO is an analog quantity, and the correction value given from the correction value input circuit 80 or the temperature correction table memory 30 is a digital quantity, the D/A conversion circuit 34 is provided between them.

In this way, a correction value is obtained at each temperature, each data is input into the computer system 90, a correction table is created, and the correction table is written into the temperature correction table memory 30A using a ROM writer or the like.

In this way, after creating the temperature correction table memory 30A, the oscillation frequency correction operation is performed by measuring the ambient temperature in which the oscillator is placed using the temperature measuring means 20, and calculating the correction value at that temperature. The digital correction value is read from the correction table memory 30A, converted to an analog value by the D/A conversion circuit 34, and inputted to the VCO 10 to perform temperature correction.

[Problem to be solved by the invention]

In the conventional example described above, first, the ambient temperature of the TCO is changed within a temperature range in which the characteristics are to be guaranteed, and a correction value is obtained at each temperature, and a high-precision frequency counter is used to write the temperature correction table memory using a ROM writer or the like. , required large-scale equipment such as a computer system equipped with a data input/output mechanism, and required long hours of work by skilled workers.

The present invention provides, within the scope of guaranteeing the characteristics of the temperature compensated oscillation circuit,
The purpose of the present invention is to provide a method for automatically creating a temperature correction table for a temperature controlled oscillator circuit, which automatically creates a temperature correction table by changing the temperature and automatically generating a correction value at each temperature point. do.

The VCOIO, the phase comparison means 40, and the signal generation means 50 constitute a phase-locked loop, and providing such means is a means for solving this problem.

[Means to solve the problem]

FIG. 1 shows a block diagram illustrating the principle of the invention.

10 in the block diagram of the principle of the present invention shown in FIG. 1 is ■CO
20 is a temperature measurement means, 30 is a temperature correction table memory, 40 is a phase comparison means for comparing the phases of the reference clock and the output clock of the vCO, and 50 is a phase comparison means 40 whose phase is locked. like vco
60 is a signal generation means for giving a correction signal to io;
It is a change detection means for detecting a change. [Function] By providing the TCO with a phase comparison means 40 and a signal generation means 50, a phase locked loop is constructed.

Here, the temperature is changed within a temperature range that guarantees the TCO characteristics, and the change detection means 60 detects the minimum 1 of the temperature change.
Each time a change in unit is detected, it is confirmed that the phase comparison means 40 has achieved phase lock.

The value indicated by the signal generating means 50 at that time is the correction value to be sought, and by writing this correction value to the address specified by the temperature measurement value in the temperature correction table memory 30, the temperature correction table is automatically created. It becomes possible to create.

〔Example〕

The gist of the present invention will be explained in detail below with reference to the embodiment shown in the first figure.

FIG. 2 is a bronc diagram illustrating an embodiment of the present invention,
Change detection means 60 serves as temperature correction table memory 30.
a write control circuit 31 that detects a minimum one-unit change in temperature and generates a write signal when the phase comparison means 40 confirms phase lock; and a signal A indicating that a temperature correction table is being created. , a two-man powered AND circuit 32 which inputs the output of the write control circuit 31 and writes the output into the correction table memory 30.
, a D/A conversion circuit 34 which converts the correction value given by digital data into an analog value and inputs it as a control voltage of VCOIO, and a temperature correction table memory as an input correction signal of the D/A conversion circuit 34. 30A and a selection circuit 33 for selecting a signal from the signal generating means 50, and a temperature correction table memory 30A consisting of a read-only memory.

In the configuration described above, the temperature is gradually varied over the entire temperature range that compensates for the characteristics of the temperature compensated oscillator.

Since the oscillation frequency changes when the temperature changes, the signal generating means 50 generates a correction signal using a digital code so that the phase comparing means 40 is phase locked.

While creating the temperature correction table, the input terminal A of the selection circuit 33
Since "1" is given to "1", the input signal of the selection circuit 33 selects the correction signal generated by the signal generation means 50,
The correction signal is converted into an analog correction value by the D/A conversion circuit 34 and inputted to C010, the oscillation frequency is converted, and the phase comparator 40 locks the phase.

During such an operation, when the change detection means 60 detects a minimum one-step change in temperature measurement and the phase comparison means 40 locks the phase, the write control circuit 31 outputs "1".
generates a signal.

"1" is input to the input terminal A of the AND circuit 32 while the temperature correction table is being created, and when "1" is generated from the write control circuit 31, the output of the AND circuit 32 becomes "1". The value indicated by the signal generating means 50 is written as a correction value at that temperature into the address corresponding to that temperature in the temperature correction table memory 30A.

In this way, each time the temperature is changed and the phase comparison means 40 locks the phase, the value indicated by the signal generation means 50 is set as the correction value at that temperature, and the temperature correction table memory 3
By writing to 0A, it is possible to automatically create a temperature correction table.

(Effects of the Invention) According to the present invention as described above, it is possible to automatically create a temperature correction table for a temperature compensated oscillator without using a large-scale measuring instrument or computer system.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating the principle of the present invention, FIG. 2 is a block diagram illustrating an embodiment of the present invention, and FIG. 3 is a block diagram illustrating a conventional example. In the figure, 10 is a voltage controlled oscillator, 20 is a temperature measurement means, 30 and 30A are temperature correction table memories, 31 is a write control circuit, 32 is an AND circuit, 33 is a selection circuit, 34 is a D/A conversion circuit, 40 50 is a phase comparison means; 50 is a signal generation means; 60 is a change detection means; 70 is a frequency counter; 80 is a correction value input circuit; 90 is a computer system; FIG. 1 is a block diagram illustrating the principle of the present invention. Block diagram illustrating an example Figure 2

Claims (1)

[Claims] A method for automatically creating a temperature correction table for a temperature compensated oscillator circuit, comprising: a voltage controlled oscillator (10); a temperature measuring means (20);
A temperature compensated oscillator circuit consisting of a temperature compensation table memory (30) includes: phase comparison means (40) for comparing the phases of the output clock of the voltage controlled oscillator (10) and the reference clock; and the phase comparison means (40). Signal generating means (50) for applying a correction signal to the voltage controlled oscillator (10) so as to achieve phase lock; and change detecting means for detecting that the temperature measuring means (20) has changed by the minimum one unit of temperature measurement. (60) is provided, and the ambient temperature of the temperature compensated oscillation circuit is changed within a temperature range that guarantees the characteristics, and each time the change detecting means (60) detects a minimum one unit change in temperature, the phase change is changed. Confirm that the comparison means (40) is phase-locked, and write the value indicated by the signal generation means (50) at that time to the address specified by the temperature measurement value in the temperature correction table memory (30). A method for automatically creating a temperature compensation table for a temperature compensated oscillator circuit by automatically creating a temperature compensation table.