JPH04198765A - Measuring method and measuring device for resonance frequency of resonator - Google Patents

Abstract

PURPOSE:To perform high-precision measurement by calculating the dielectric resonance frequency based on the oscillation frequency of an oscillating loop circuit. CONSTITUTION:A switch SW1 is turned off, a switch SW2 is turned on, the mode is set to the measuring operation mode, an oscillating loop circuit is connected between coils 23, 24, and the generated oscillation frequency is measured by a frequency counter 35 and stored in an MPU 40. The transmission phase of a dielectric resonator 11 is calculated with it. The resonance frequency of the resonator 11 is calculated, and the result is displayed on a display 41. The switch SW2 is turned off, the switch SW1 is turned on, and the mode is set to the filtering mode to complete the measuring process. High-precision measurement can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for measuring the resonant frequency of a resonator having a predetermined load Q, such as a dielectric resonator.

[Prior Art] A resonant frequency measuring device for measuring the resonant frequency of a dielectric resonator to be measured is proposed in Japanese Patent Publication No. 61-22911.

This resonant frequency measurement device includes a support on which the dielectric resonator to be measured is placed, and a pair of input/output means that couple with the dielectric resonator to be measured when the dielectric resonator is placed on the support. , and an amplifier, and when the dielectric resonator to be measured is placed on a support, the output signal of the amplifier is applied to one of the pair of input/output means, and the signal is selected by the dielectric resonator to be measured. The present invention is characterized by having an oscillation circuit that oscillates when the oscillation condition is satisfied by applying the signal from the other input/output means to the input side of the amplifier, and a frequency meter that can directly read the oscillation frequency value of this oscillation circuit. It is said that

In the conventional resonant frequency measuring device configured as described above, the oscillation frequency of the oscillation circuit is measured as the resonant frequency of the dielectric resonator to be measured.

[Problems to be Solved by the Invention] However, with this conventional resonant frequency measuring device, (a) when the load Q of the resonant frequency is large enough to satisfy the load Q force, or (b) when the measurement frequency range is sufficiently narrow, When the frequency characteristics of devices other than the dielectric resonator and the electrical length of the line can be ignored, the oscillation frequency of the oscillation circuit can be measured as the resonant frequency of the dielectric resonator under test, but if the above conditions are met. When this is not true, as shown in FIG.
Therefore, there was a problem in that the resonant frequency of the dielectric resonator to be measured could not be accurately measured. FIG. 4 is a graph of a characteristic example of the frequency deviation Δf when the transmission phase of the oscillation loop is 12π and the load Q (Q, ) is 4000.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a measuring method and a measuring device that can measure the resonant frequency of a resonator having a predetermined load Q with higher accuracy than in the conventional example.

[Means for Solving the Problems] A method for measuring the resonant frequency of a resonator according to claim 1 of the present invention includes an amplifying means, electrically connected to a resonator having a predetermined load Q, and a resonator having a predetermined load Q. The oscillation frequency of an oscillation signal generated in an oscillation loop circuit having a transmission phase is measured, and the resonance frequency of the resonator is determined based on the measured oscillation frequency, the transmission phase of the oscillation loop circuit, and the load Q of the resonator. It is characterized by calculating and measuring.

Further, the resonant frequency measuring device of a resonator according to claim 2 of the present invention includes an oscillation loop circuit that includes an amplification means, is electrically connected to a resonator having a predetermined load Q, and has a predetermined transmission phase. and a frequency measuring means for measuring the oscillation frequency of the oscillation signal generated in the oscillation loop circuit, based on the oscillation frequency measured by the frequency measuring means, the transmission phase of the oscillation loop circuit, and the load Q of the resonator. and calculating means for calculating the resonant frequency of the resonator.

[Operation] With the above configuration, the oscillation frequency of the oscillation signal generated in the oscillation loop circuit is measured, and the measured oscillation frequency, the transmission phase of the oscillation loop circuit, and the load Q of the resonator are calculated. The resonant frequency of the resonator can be calculated and measured based on . In the present invention,
Rather than measuring the oscillation frequency measured in the oscillation loop circuit connected to the resonator as the resonant frequency of the resonator as in the conventional example, it is better to measure the oscillation frequency of the oscillation signal generated in the oscillation loop circuit. Since the resonant frequency of the resonator is calculated based on the measured oscillation frequency, the transmission phase of the oscillation loop circuit, and the load Q of the resonator, the resonant frequency of the resonator can be calculated with higher accuracy than in the conventional example. The resonance frequency can be measured accurately.

[Example 7] Hereinafter, an apparatus for measuring the resonant frequency of a dielectric resonator according to an embodiment of the present invention will be described in the order of the following items with reference to the drawings.

(1) Configuration of the device for measuring the resonant frequency of a dielectric resonator (2) Principle for measuring the resonant frequency of the dielectric resonator (3) Measurement flow of the measuring device The measuring device of this example has a known load Q. The dielectric resonator 11 to be measured is electrically connected to an oscillation loop circuit including an amplifier 33, oscillated at an oscillation frequency f1, the oscillation frequency f1 is measured, and the measured oscillation frequency f,
This method is characterized in that the resonant frequency f0 of the dielectric resonator 11 is calculated based on the following.

(1) Configuration of a device for measuring the resonant frequency of a dielectric resonator FIG.
FIG. 2 is a longitudinal cross-sectional view of the dielectric resonator 11 shown in the figure and the shield case 10 that houses it. Here, the dielectric resonator 11 has a known load Q (Q,).

This measuring device has two operation modes: a filtering operation mode in which the dielectric resonator 11 operates as a bandpass filter, and a measurement operation mode in which the resonant frequency f0 of the dielectric resonator 11 is measured.

As shown in FIGS. 1 and 2, the cylindrical dielectric resonator 11 to be measured has the same coefficient of linear expansion as the dielectric resonator 11 at the center of the cylindrical shield case 10. It is placed on a support stand 14. This dielectric resonator 11 is made of, for example, TiO2 as a main component and Mg0S as a main component.
It is a ceramic dielectric resonator made of a mixture of oxides such as Bad, ZrO2, etc., and the dielectric resonator 11 of this embodiment has a power of about 80 in the T E 61 a mode which is the fundamental mode.
Resonant frequency f of 0MHz. has. Further, a cylindrical dielectric 12 is provided inside the cylinder of the dielectric resonator 11 and is supported by a shaft 15.
By moving in the direction of arrow A1 and moving the dielectric 12 within the gradient of the electric field of the dielectric resonator 11, the resonant frequency f0 of the dielectric resonator 11 can be finely adjusted.

The shield case 10 is constructed by baking a silver electrode onto the outer surface of a cylindrical casing made of ceramic having the same coefficient of linear expansion as the dielectric resonator 11 for electromagnetic shielding. As shown in FIG. 2, the magnetic field H of the dielectric resonator 11 is coupled to the inner surface of the shield case 10 at four positions spaced apart by an angle of 90 degrees from each other around the center of the cylinder. For example, one turn coil 21, 22, 23° 24 for signal input/output.
is provided. Here, coils 21 and 22 used in the filter operation mode are provided facing each other with the dielectric resonator 11 in between, and coils 23 and 24 used in the measurement operation mode are provided with the dielectric resonator 11 in between. They are placed opposite each other.

In the filter operation mode, the switch SW1 is turned on and the switch SW2 is turned off, and a signal in the approximately 800 MHz band output from the high frequency signal generator 1 is input to the coil 21 via the input terminal T1 and the switch SWI. After
The input signal is filtered by the dielectric resonator 11 . The filtered signal is output from the coil 22 to the load 2 via the output terminal T2.

On the other hand, in the oscillation operation mode, the switch SWI is turned off and the switch SW2 is turned on.

At this time, an oscillation signal is generated in an oscillation loop circuit connected between the coils 23 and 24 and configured so that oscillation conditions, which will be described in detail later, are satisfied.

When switch SW2 is turned on, the oscillation loop circuit shown in FIG. 1 is electrically connected between coils 23 and 24, and the oscillation signal output from coil 24 has an amplification degree of A
amplifier 33 and ports 34a, 3 of the directional coupler 34
The signal is output to the filter 23 via the transmission line connected between the terminals 4b and 4b and the switch SW2. The above two switches SWl and SW2 are switched and controlled by a microprocessor unit (hereinafter referred to as MPU) 40 which is a control device of the measuring device, as will be described in detail later.

A port 34d of the directional coupler 34 that detects an oscillation signal that is a traveling wave passing through the transmission line between the ports 34a and 34b is connected to a frequency counter 351; a port that detects the reflected wave passing through the transmission line. 34c is terminated by a load 34e with a predetermined characteristic impedance.

This frequency counter 35 measures the frequency of the oscillation signal detected at the port 34d, and outputs data fm of the measured frequency to the MPU 40.

The MPU 40 controls the measurement device and controls the dielectric resonator 11.
a CPU (not shown) that measures the resonance frequency f, and a ROM (not shown) that stores a control program for controlling the measuring device and data necessary for executing the control program. , a RAM (not shown) used as a working memory of the CPU, and a switch SWI.

SW2, frequency counter 35 and CRT display 41
The input/output port circuit (not shown) is connected to the input/output port circuit and operates as an interface circuit. This MPU4
0 are the switches SW1.0, which will be described in detail later. SW
2, and also receives the measured oscillation frequency data fm from the frequency counter 35, calculates the transmission phase θ1 of the dielectric resonator 11 based on the received oscillation frequency data fm, and performs dielectric resonance. Known load Q of device 11
The resonant frequency f0 of the dielectric resonator 11 is calculated based on (QL) and the transmission phase θ calculated above, and these data are displayed on the CRT display 41.

(2) Principle of Measuring the Resonant Frequency of a Dielectric Resonator The oscillation conditions in the oscillation loop circuit shown in FIG. 1 are expressed by the following equation.

Re(A・β+) = 1 − (1a) 1
m(A·βl) =O·(1b) Here, A is the amplification degree of the amplifier 33, and β1 is the feedback amount in the oscillation loop circuit.

In the above oscillation loop circuit, the above equation (1a) and (1b
) When the oscillation condition expressed by the formula is satisfied, an oscillation signal having a certain oscillation frequency f1 is generated.

The oscillation loop circuit shown in FIG. 1 in this embodiment has a predetermined transmission phase so that the above equations (la) and (1b) are satisfied.

[r
ad], the transmission phase θ of the dielectric resonator 11 is expressed by the following equation.

Here, n is an integer, and the transmission phase θ1 is a device constant that can be measured in advance with a network analyzer or the like in the oscillation loop circuit.

As is clear from the above equation (2), by measuring the oscillation frequency f in the oscillation loop circuit, the transmission phase θ1 of the dielectric resonator 11 in the oscillation loop circuit is determined.
can be found.

When the resonant frequency of the resonator is fo, the following relationship generally holds between the transmission phase θ of the resonator and its load Q (Q,).

Therefore, by applying the above oscillation loop circuit to the above equation (3), the following equation is obtained.

From the above equation (4), the resonance frequency f is expressed by the following equation.

Here, the dimensionless constant F1 is expressed by the following equation.

Therefore, after measuring the oscillation frequency f of the oscillation signal generated in the oscillation loop circuit, the transmission phase θ1 of the dielectric resonator 11 is calculated by substituting the measured frequency f into the equation (2) above. can do. Next, the calculated transmission phase θ1 and the known load Q of the dielectric resonator 11
After substituting (QL) into the above equation (6) to calculate the value of the above constant F, the value of the above calculated constant F is calculated using the above (5).
The resonance frequency f0 of the dielectric resonator 11 can be calculated and measured by substituting it into the equation.

(3) Measurement flow of the measuring device FIG. 3 is a flowchart showing the measurement flow of the measuring device of FIG. 1 in the measurement operation mode, and the measurement flow of the measuring device will be explained with reference to FIG.

First, in step #1, the switch SWI is turned off, the switch SW2 is turned on, the measuring device is set to the measuring operation mode, and the oscillation loop circuit is connected between the coils 23 and 24.

Next, in step #2, the oscillation frequency f1 of the oscillation signal generated in the oscillation loop circuit is measured by the frequency counter 35, and the data fm is sent to the MPU 40.
The frequency is stored in the internal RAM as the oscillation frequency f1. moreover,
In step #3, the measured oscillation frequency f1
is substituted into the above equation (2) to calculate the transmission phase θ1 of the dielectric resonator 11, and the calculated result is stored in the RAM.

Furthermore, in step #4, the value of the constant F1 is calculated by substituting the transmission phase θ1 calculated above into the above equation (6), and then the value of the constant F1 calculated above is substituted into the above equation (5). Then, the resonant frequency fo of the dielectric resonator 11 is calculated, and the calculated result is displayed on the CRT display 41. Finally, in step #5, switch SW2
is turned off and the switch SWI is turned on to set the measuring device to the filtering operation mode and end this measurement process.

As explained above, the dielectric resonator 11 to be measured having a known load Q is electrically connected to the oscillation loop circuit including the amplifier 33, and the oscillation frequency f is set.

, measure the oscillation frequency f1, calculate the resonant frequency f of the dielectric resonator 11 based on the measured oscillation frequency f, and measure the resonant frequency fo of the dielectric resonator 11. Therefore, the accuracy is higher than that of the conventional example.
Resonant frequency f of dielectric resonator 11 with known load Q
, can be measured accurately.

In the above embodiments, a measuring method and a measuring device for measuring the resonant frequency of a dielectric resonator 11 having a known load Q have been described, but the present invention is not limited to this, and the present invention is not limited to this. Other types of known loads, such as resonators, Q
It can be applied to resonators with

[Effects of the Invention] As detailed above, according to the present invention, like the conventional example,
Instead of measuring the oscillation frequency of the oscillation signal that oscillates in the oscillation loop circuit to which the resonator to be measured is electrically connected, the oscillation frequency of the oscillation signal generated in the oscillation loop circuit is measured as the resonant frequency of the resonator. However, since the resonant frequency of the resonator is calculated and measured based on each of the measured oscillation frequencies, the transmission phase of the oscillation loop circuit, and the load Q of the resonator, it can be measured with higher precision than in the conventional example. , there is an advantage that the resonant frequency of the resonator can be measured.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a device for measuring the resonant frequency of a dielectric resonator according to an embodiment of the present invention, and FIG. 2 is a vertical cross-sectional view of the dielectric resonator of FIG. 1 and a shield case housing it. FIG. 3 is a flowchart showing the measurement process in the measurement operation mode of the measuring device shown in FIG. 1, and FIG. 4 is a graph showing the deviation between the resonant frequency and the oscillation frequency with respect to the resonant frequency of the dielectric resonator. 11... Dielectric resonator, 23.24... Coil, 3
3... Amplifier, 34... Directional coupler, 35...
Frequency counter, 40... microprocessor unit) (MPU),
SW2...Switch. Patent applicant: Murata Manufacturing Co., Ltd. Representative: Patent attorney: 1 person, Ao-Haku and Ao-Haka Figure 2

Claims (2)

[Claims] (1) Measuring the oscillation frequency of an oscillation signal generated in an oscillation loop circuit equipped with an amplification means, electrically connected to a resonator having a predetermined load Q, and having a predetermined transmission phase;
A method for measuring the resonant frequency of a resonator, comprising calculating and measuring the resonant frequency of the resonator based on the measured oscillation frequency, the transmission phase of the oscillation loop circuit, and the load Q of the resonator. . (2) an oscillation loop circuit equipped with an amplification means, electrically connected to a resonator having a predetermined load Q, and having a predetermined transmission phase; and a frequency for measuring the oscillation frequency of the oscillation signal generated in the oscillation loop circuit. and a calculation means for calculating the resonant frequency of the resonator based on the oscillation frequency measured by the frequency measurement means, the transmission phase of the oscillation loop circuit, and the load Q of the resonator. A device for measuring the resonant frequency of a featured resonator.