JPS603564A - Resonator characteristic measuring and selecting device - Google Patents

Abstract

PURPOSE:To measure quickly and exactly a resonator characteristic of VHF- UHF bands according to the oscillation frequency and the output level, by providing a positive feedback oscillator provided with a narrow band band pass filter, a fixed phase shifter and an amplifier. CONSTITUTION:A positive feedback oscillator is constituted of a loop of a high frequency amplifier 401 - a narrow band band pass filter 402 - a power distributor 403 - a fixed phase shifter 404. A part of an oscillating output passes through the power distributor 403, also passes through other power distributor 405, its frequency and output level are monitored simultaneously by a frequency counter 406 and a wattmeter 407, respectively, and the resonance frequency of a resonator, and a no-load Q are measured. In case when said frequency and output level are within some range, the resonator can be selected by adding a means for deciding that the resonator is a non-defective one. In this way, it is the feature of this device to measure the resonating characteristic of a resonator to be measured 408 from the oscillation frequency output level of the positive feedback oscillator, and a no-load Q of the resonator, and a resonance frequency can be measured easily and quickly without using an expensive measuring instrument.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a resonator characteristic measurement and selection device that measures the resonant frequency and no-load Q characteristics of a resonant double pager used in the VHF and UHF bands using a simple method. It is something.

Conventional configuration examples and their problems Since the characteristic of a resonator under VHFHF is a lumped constant circuit, the resonant frequency no-load Q is almost always measured with a Q meter. However, when the frequency becomes higher still, the Q-meter method cannot be applied because it is necessary to treat the circuit as a distributed constant circuit with floating inductance and capacitance. Therefore, in the past, the resonant characteristic (curve) was actually measured using a network tenalizer or a sweep oscillator and a high-precision detector for measuring a high-Q resonator on VHFHF, and the resonant frequency and no-load Q were calculated from the data. He took a method of

Although this method is the best method for obtaining accurate data, it has drawbacks such as expensive measuring equipment, time-consuming measurement, and inability to directly obtain correlation between no-load Q and measured values. However, there remained a cost problem in quickly measuring a large number of resonators.

3 Purpose of the Invention The purpose of the present invention is to provide VHF-
It is an object of the present invention to provide a resonator characteristic measurement and selection device that quickly and accurately measures resonator characteristics in the UHF band.

Structure of the Invention The present invention achieves the above object, and includes a positive feedback oscillator including at least a narrowband bandpass filter, a fixed phase shifter, and an amplifier configured to be able to incorporate a resonator under test. , there is provided a resonator characteristic measuring and selecting device characterized in that the resonator characteristics of the resonator to be measured are measured from the oscillation frequency and output level of the positive feedback oscillator.

Description of examples The basic configuration of an embodiment of the present invention is shown in FIG.

In FIG. 1, 1o1 is an amplifier, 1o2 is a one-stage narrowband bandpass filter configured using a resonator to be measured,
103 is a phase shifter, and this entire loop forms a positive feedback oscillator. Normally, a positive feedback oscillator feeds back the output of the amplifier to the input, so that the phase difference is 360°×n (n=o, ±1
．． ±2. ), but since there are many oscillation points up to this point, a bandpass filter etc. is used to give the amplitude characteristics a frequency characteristic, and the oscillation frequency is uniquely determined. Designed to be determined. The present invention attempts to measure the resonator characteristics by utilizing the relationship between the bandpass filter used in this oscillator and the oscillation frequency and oscillation output level. FIG. 2 shows the structure and characteristics of a one-stage bandpass filter used in this embodiment. In a, 2Q1, 202 is the input/output terminal of the filter, 204
, 205 are coupling capacitors, and 203 is a resonator lever to be measured. In this example, a quarter wavelength coaxial type resonator is shown. This resonator 203 is configured to be easily connected and fixed to a circuit by crimping or the like in order to quickly measure a large number of resonators. Now, if we reduce the coupling capacitance of the filter to realize a narrow band filter, the amplitude and phase characteristics of the filter will have a large change near the resonant frequency fr of the resonator 203, as shown in Figure 2. It becomes possible. Since the frequency characteristics of the 6-page phase shifter 103 shown in FIG. 1 can usually be designed to be small, the resonance frequency fr and the oscillation frequency fO when configured as an oscillator almost match. This relationship is shown in Figure 3a. In addition, since the filter 102 has a narrow band as described above and has a large insertion loss, if it is configured as a positive feedback oscillator, the circuit can be designed in a region where the output of the amplifier is not saturated. In addition, the insertion loss of the filter is determined by the resonator 2 used when the coupling is the same.
The insertion loss is inversely proportional to the no-load Q of 03, that is, the larger Q is, the smaller the insertion loss is. Therefore, if this filter constitutes a positive feedback oscillator, the oscillation output level and the no-load Q of the resonator can be made to have a relationship close to direct proportion as shown in FIG.

Since the oscillation frequency and output level of the oscillator can be easily measured, it is possible to measure the resonant frequency and no-load Q of the resonator by measuring the oscillator characteristics.

This method is particularly useful in the process of selecting a large number of resonators in a short time.

FIG. 4 shows a specific configuration of an embodiment of the present invention.

This example is a device that uses a frequency counter and a wattmeter to perform high-speed selection of resonators. In the figure, 401
is a high frequency amplifier, and 402 is a resonator 40 to be measured.
A narrowband bandpass filter incorporating 8 as a resonant element,
403 is a power distribution field (hybrid circuit) and 404u is a fixed phase shifter. High frequency amplifier 401 - narrowband bandpass filter 402 - power divider 403 - fixed phase shifter 404
The loop constitutes a positive feedback oscillator. A part of the oscillation output passes through the power divider 403 and is further transmitted to another power divider 40.
5, its frequency is simultaneously monitored by a frequency counter 406 and its output level is monitored by a power meter 407, and the resonant frequency and no-load Q of the resonator are measured. Resonators can be selected by adding a means for determining that a resonator is good if the frequency and output level are within a certain range.

By the way, in the example of FIG. 4, the measurable frequency range is narrow, so if a wide band is to be achieved, the oscillation frequency band of the positive feedback oscillator must be widened.

This can be dealt with by providing the phase shifter 404 with a function of switching the phase amount.

7be' Also, although a coaxial resonator was used as the resonator in this example, this method can be applied to any structure of the resonatorζ(
! : is forever. Further, by employing means for fixing the resonator to the filter 402 by crimping or the like, rapid measurement becomes possible.

Effects of the Invention As described above, the present invention provides a narrowband bandpass filter configured to be able to incorporate a resonator under test, a fixed phase shifter,
Provided is a resonator characteristic measuring and selecting device, comprising a positive feedback oscillator including at least an amplifier, and measuring the resonator characteristics of a resonator to be measured from the oscillation frequency output level of the positive feedback oscillator. This method provides a means to easily and quickly measure the unloaded Q and resonant frequency of a resonator without using expensive measuring equipment, and can be applied to high-speed selection of resonators, and its industrial value is extremely high. big.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a positive feedback oscillator, which is the basic configuration of an embodiment of the present invention, FIG. 2a is a configuration diagram of a narrowband filter used in the positive feedback oscillator, and FIG.
3a and 3b are characteristic diagrams showing the correlation between oscillator characteristics and resonator characteristics, and FIG. 4 is a block diagram showing a specific configuration of an embodiment of the present invention. 401... Amplifier, 4o2... Narrow band pass filter, 403, 405... Out-of-power arrangement, 4o4... Fixed phase shifter, 406... ...
...Frequency counter, 407...Water meter, 4o
8...Resonator to be measured. Name of agent: Patent attorney Toshio Nakao and 1 other person λ Figure 1 Figure 2 r Frequency Figure 3 Excavation frequency Nine-shouldered Satoru output ν Bell

Claims (3)

[Claims] (1) A positive feedback oscillator including at least a narrowband bandpass filter configured to be able to incorporate a resonator under test, a fixed phase shifter, and an amplifier; the oscillation frequency and output of the positive feedback oscillator; A resonator characteristic measuring and selecting device characterized by measuring the resonator characteristics of a resonator to be measured based on a level. (2) The resonator characteristic measurement and selection device according to claim 1, characterized in that the output of the positive feedback oscillator is simultaneously measured using a frequency counter and a wattmeter. (3) A resonator characteristic measurement and selection device according to claim 1 or 2, characterized in that the resonator to be measured is mechanically compressed and incorporated into a narrow band pass filter. .