JP2655072B2 - High frequency signal generator temperature test equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature test apparatus,
In particular, the present invention relates to a temperature test apparatus for measuring a change in magnitude of a high-frequency signal generated by a high-frequency signal generator due to temperature.

[0002]

2. Description of the Related Art The magnitude of an output high-frequency signal changes for each temperature if the electrical operation state of the high-frequency signal generator has a characteristic dependent on temperature. There is a temperature test apparatus for measuring the amount of change in the magnitude of a high-frequency signal generated by a high-frequency signal generator due to temperature.

FIG. 2 is a block diagram showing an example of a conventional temperature test apparatus. A high-frequency signal generator serving as a device under test 5 is installed inside the temperature test tank 1, and a high-frequency signal is output to an output terminal 6 of the high-frequency signal generator. In order to take out the high-frequency signal of the test object output terminal 6 out of the temperature test chamber,
A coaxial cable 2 for signal extraction is prepared, one end is connected to the output terminal 6 under test, and the other end is pulled out of the temperature test chamber 1. The detector 10 is connected to the other end, and the output is displayed on the display unit 12. Here, the detector 10 generally has a characteristic that easily depends on the temperature.
It is necessary to set up a fixed temperature environment outside the temperature test tank.

The high-frequency signal generator 5 installed inside the temperature test chamber 1 changes the magnitude of the high-frequency signal output to the DUT output terminal 6 depending on the temperature environment created by the temperature test chamber 1. . The high-frequency signal at the output terminal 6 under test is taken out of the temperature test chamber by the coaxial cable 2 for taking out the signal, and the high-frequency signal is converted into a direct-current signal by the detector 10 connected thereto. The value obtained by calibrating the signal is displayed as the magnitude of the high-frequency signal.

With these operations, by reading the magnitude of the signal indicated on the display unit for each temperature set in the temperature test chamber, the magnitude of the magnitude of the high-frequency signal generated by the high-frequency signal generator of the device under test is determined. The amount of change can be measured.

[0006]

In this conventional temperature test apparatus, a coaxial cable for signal extraction is used to connect a high-frequency signal generator inside the temperature test chamber and a detector outside the temperature test chamber. In order to know the magnitude of the high-frequency signal at the terminal, it is necessary to correct the loss caused by the passage of the high-frequency signal through the coaxial cable with respect to the measured value shown on the display unit.

Further, since the coaxial cable is installed inside the temperature test chamber similarly to the high-frequency signal generator, the amount of loss varies depending on the temperature. Must be measured in advance. At the same time, the amount of loss must be measured for each frequency of the high-frequency signal generated by the high-frequency signal generator, and the number of correction values to be prepared becomes enormous, making it extremely difficult to obtain the correction values.

Further, there is a problem that the reproducibility of the correction value once obtained is lost due to the change over time when the coaxial cable for signal extraction is repeatedly used for a temperature test.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the need for previously acquiring a loss amount of a coaxial cable for signal extraction as a correction value, and to realize a loss occurring in the coaxial cable for signal extraction in real time for each measurement. An object of the present invention is to provide a temperature test apparatus capable of detecting an amount, performing correction, and measuring the magnitude of a high-frequency signal output from a high-frequency signal generator to an output terminal for each temperature.

For this reason, in the temperature test apparatus of the present invention, in addition to the conventional temperature test apparatus, a branch circuit connected to the first coaxial cable for signal extraction outside the temperature test tank, and one end of the branch circuit connected to one end of the branch circuit. A second coaxial cable having the same material, the same structure, the same diameter, and the same length as the first coaxial cable, which is connected, installed inside the temperature test chamber again, and the other end is taken out of the temperature test chamber; A pair of first and second detectors connected to the other end of the coaxial cable and the other end of the branch circuit, respectively, and output from the high-frequency signal generator based on the magnitudes of the signals obtained by these detectors. An arithmetic unit for calculating the magnitude of the high-frequency signal and a display unit for outputting the calculation result are provided.

[0011]

The loss of the second coaxial cable is determined from the difference between the output of the first detector and the output of the second detector. Since the first coaxial cable and the second coaxial cable are made of the same material, the same structure, the same diameter, and the same length, the loss given in the temperature test chamber has the same value. Therefore,
The amount of loss of the first coaxial cable is known. This determines the magnitude of the high-frequency signal generated by the high-frequency signal generator,
Can be displayed.

[0012]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a temperature test apparatus according to one embodiment of the present invention. This temperature test apparatus is a temperature test tank 1 capable of obtaining a temperature environment in a temperature test range for performing a test.
It has. The high frequency signal generator, which is the device under test 5,
It is installed inside the temperature test tank 1. High frequency signal generator 5
Is output to the device under test output terminal 6. In order to take out the high-frequency signal to the outside of the temperature test chamber 1, a coaxial cable 2 for taking out the signal is provided in the temperature test chamber 1, and one end is connected to the output terminal 6 under test.
The other end is connected to a branch circuit input terminal 7 of a branch circuit 4 installed outside the temperature test chamber 1. The branch circuit 4 has a configuration for branching a signal input to the input terminal 7 to output terminals 8a and 8b.

In the temperature test chamber 1, a coaxial cable 3 for measuring the amount of loss is further provided. This coaxial cable 3
The same material and the same structure as the signal extraction coaxial cable 2
They have the same diameter and the same length. One end of this coaxial cable 3
The other end is connected to the output terminal 8 b of the branch circuit 4, and the other end is connected to a loss measurement signal extraction terminal 9 outside the temperature test chamber 1.

A detector 10 is connected to an output terminal 8a of the branch circuit 4.
a, and a detector 10b is connected to the loss measurement signal extraction terminal 9. The detector detects the high-frequency signal and converts it into a DC signal representing the magnitude of the high-frequency signal.

The output terminals of the detectors 10a and 10b are connected to a calculation unit 11, and the calculation unit 11 is connected to a display unit 12. The calculation unit 11 calculates a DC signal representing the magnitude of the high-frequency signal output to the output terminal 6 of the high-frequency signal generator 5 from the DC signals output from the detectors 10a and 10b.
The display unit 12 displays the DC signal.

As described above, the coaxial cable 2 for signal extraction and the coaxial cable 3 for loss measurement use the same material, the same structure, the same diameter, and the same length.
The number of use repetitions of these two coaxial cables is made the same. This is to ensure that the same loss occurs under the same conditions in these two coaxial cables.

In the temperature test apparatus having the above-described configuration, the high-frequency signal output to the test object output terminal 6 is transmitted through the coaxial cable 2 for signal extraction under an arbitrary temperature condition set by the temperature test chamber 1. Shown in FIG. 2, and further divided by the branch circuit 4 into two output terminals 8a and 8a.
b. In this embodiment, the magnitude of the high-frequency signal at the DUT output terminal 6 is P ₆ , the magnitude of the high-frequency signal at the branch circuit output terminal 8 _a is P _a , and the amount of loss generated in the coaxial cable 2 for signal extraction is L. ₂ , and if the branch circuit 4 does not cause loss and the signal is completely branched into two,
In decibels, it holds the relationship _{P a = P 6 -L 2 -3} . The attenuation of 3 dB is due to two branches by the branch circuit 4. Branch circuit output terminal 8
The size of the high-frequency signal generator in b are the same as P _a.

Assuming that the loss amount of the loss measuring coaxial cable 3 is L ₃ and the magnitude of the high-frequency signal at the loss measuring signal extraction terminal 9 is P ₉ , P ₉ = P _a −L in decibels. ₃ = P ₆ −L ₂ −3−L ₃

In addition to these conditions, the coaxial cable 2 for signal extraction and the coaxial cable 3 for loss measurement are made of the same material.
Because of the same structure, the same diameter, and the same length, strain due to mechanical expansion and contraction due to changes in the temperature environment in which it is used occurs under the same conditions, and as a result, the amount of electrical loss also increases Will change and take the same value. Accordingly, the loss L generated in the coaxial cable 2 for signal extraction
₂ and the loss L generated in the loss measuring coaxial cable 3
_3, always from being installed inside temperature test chamber 1, becomes relatively equal change its temperature environment, the size P _a of the high-frequency signal in the branch circuit output terminal 8a, loss measurement signal The difference in the magnitude P ₉ of the high-frequency signal at the extraction terminal 9 is caused by the loss L ₂ generated in the signal extraction coaxial cable _2.
Becomes That is, _{P a -P 9 = L 3 (} = L 2).

The detector 10a has a branch circuit output terminal 8a
Is input to the detector 10b.
A high frequency signal at the loss measurement signal extraction terminal 9 is input. Detector 10a is by detecting a high-frequency signal branching circuit output terminal 8a, to obtain a DC signal based on the magnitude P _a of the high-frequency signal. The detector 10b is by detecting a high-frequency signal loss measurement signal extraction terminal 9, to obtain a DC signal based on the magnitude P ₆ of the high-frequency signal. These detectors 10a,
The DC signal from 10b is supplied to the operation unit 11.

The operation unit 11 performs a calculation corresponding to the following equation using the supplied DC signal.

P _a + (P _a −P ₉ ) +3 By this calculation, the magnitude P ₆ of the high-frequency signal at the DUT output terminal ₆ is obtained.

The output of the arithmetic section 11 is sent to the display section 12, and the measurer is displayed with the magnitude P ₆ of the high-frequency signal at the DUT output terminal 6. The magnitude of the high-frequency signal displayed on the display unit 12 is corrected for the amount of loss that occurs in the signal extraction coaxial cable 2.

[0025]

As described above, according to the present invention, since the branch circuit, the loss measuring coaxial cable, the pair of detectors, the arithmetic unit, and the display unit are provided, the temperature generated in the signal extracting coaxial cable is provided. Each loss amount can be known from the loss amount generated in the loss amount measuring coaxial cable.

Further, since the magnitude of the high-frequency signal at the output terminal of the device under test is obtained from the signal obtained by the detector and can be displayed on the display unit, the operation is performed by a conventional temperature test apparatus. Measurement of the loss amount for compensating the signal extraction cable for each temperature and frequency, and based on the compensation value obtained in advance by the operator for the measurement value for each temperature test condition and each frequency to be measured. The result is that it is not necessary to perform the measurement while performing the correction.

In addition, the problem that the reproducibility of the previously measured correction value is lost due to the repeated use of the signal extracting cable is also solved by the repeated use of the signal extracting coaxial cable and the loss measuring cable. By making the number of times the same, the change with the passage of time occurs in the same manner, so that the measurement can be performed with the loss amount corrected.

[Brief description of the drawings]

FIG. 1 is a block diagram of a temperature test apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional temperature test device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Temperature test tank 2 Coaxial cable for signal extraction 3 Coaxial cable for loss measurement 4 Branch circuit 5 DUT (high-frequency signal generator) 6 DUT output terminal 7 Branch circuit input terminal 8, 8a, 8b Branch circuit output terminal 9 Loss measurement signal extraction terminal 10, 10a, 10b Detector 11 Operation unit 12 Display unit

Claims (3)

(57) [Claims] 1. A temperature test apparatus for measuring a change in magnitude of a high-frequency signal generated by a high-frequency signal generator due to a temperature, wherein a high-frequency signal generator serving as a device under test is installed to arbitrarily change an internal temperature. A first coaxial cable that is installed in the temperature test chamber and outputs a high-frequency signal generated by the high-frequency signal generator to the outside of the temperature test chamber; A branch circuit for branching the output high-frequency signal into a first output terminal and a second output terminal outside the temperature test chamber; and a branch circuit installed in the temperature test chamber and having one end connected to a first output terminal of the branch circuit. Is connected, and the other end is taken out of the temperature test chamber. The same material as the first coaxial cable,
A second coaxial cable having the same structure, the same diameter, and the same length; a first detector connected to a second output terminal of the branch circuit; and a second coaxial cable connected to the other end of the second coaxial cable. A second detector to be connected, an arithmetic unit for calculating the magnitude of the high-frequency signal output from the high-frequency signal generator from the DC signals obtained by the first and second detectors, and a calculation by the arithmetic unit And a display unit for outputting a result. 2. The first coaxial cable is a coaxial cable for extracting a signal, the second coaxial cable is a coaxial cable for measuring a loss amount, and the arithmetic unit is a coaxial cable of the first detector. The magnitude of the DC signal of the second detector is subtracted from the magnitude of the DC signal to obtain the loss amount of the coaxial cable for measuring the loss amount. This loss amount is determined by the loss amount of the coaxial cable for signal extraction. 2. The temperature test apparatus according to claim 1, wherein the magnitude of the high-frequency signal output from the high-frequency signal generator is calculated assuming that: 3. The temperature test apparatus according to claim 2, wherein the coaxial cable for signal extraction and the coaxial cable for loss measurement have the same number of repetitions of use.