JP7165765B2 - Signal generator and its attenuation correction method - Google Patents

Description

The present invention relates to a signal generator that generates a modulated wave in a desired frequency band.

As a signal generator for generating a modulated wave in a desired frequency band, for example, there is a signal generator that generates a modulated wave in a desired frequency band by frequency-converting an intermediate frequency signal generated by an arbitrary signal generator using a mixer or the like. Are known.

Such a signal generator is incorporated in, for example, a mobile terminal testing device for testing mobile communication terminals, and generates and outputs a signal for testing.

Patent Document 1 discloses a storage device that stores the relationship between the number of transmission slots, the attenuation setting value, and the terminal voltage control value, and an attenuation that controls the attenuation based on the attenuation setting value selected based on the number of transmission slots. and an amplifier that controls the transmission power of a transmission signal based on a terminal voltage control value selected based on the number of transmission slots, and uses the ambient temperature of the amplifier to adjust the attenuation setting value and the terminal voltage control value. Weighting is described.

As described above, some devices using semiconductor components such as attenuators and amplifiers have characteristics that change depending on the temperature.

Japanese Patent Application Laid-Open No. 2006-80992

For devices whose characteristics change with temperature, the temperature around the device is measured and the characteristics are selected based on the measured temperature. was taking a long time. In particular, equipment with non-linear characteristics requires time for adjustment.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a signal generator capable of correcting an output signal in a short period of time even if it is equipped with equipment whose characteristics change with temperature.

A signal generator according to the present invention comprises a signal generator that generates a test signal, a variable attenuator that attenuates the signal generated by the signal generator and whose characteristics change with temperature, and a signal attenuated by the variable attenuator. a level detection unit for detecting the level of the signal received from the variable attenuator; a temperature detection unit for detecting the temperature around the variable attenuator; obtaining the characteristic of the attenuation amount with respect to the parameter, obtaining the attenuation amount of the variable attenuator from the signal level detected by the level detection unit when the control parameter of the variable attenuator is set to a predetermined value, and obtaining the obtained attenuation amount and a control unit that corrects the characteristics of the variable attenuator based on the predetermined value.

With this configuration, the characteristic corresponding to the ambient temperature of the variable attenuator is corrected by the signal level detected by the level detector when the control parameter is set to the predetermined value. Therefore, even if a device whose characteristics change with temperature is provided, the output signal can be corrected in a short period of time.

Further, in the signal generator of the present invention, the control unit determines the value of the control parameter corresponding to each predetermined amount of attenuation based on the corrected characteristic of the attenuation amount with respect to the control parameter of the variable attenuator. Make the desired adjustments.

With this configuration, the value of the control parameter corresponding to each predetermined amount of attenuation is obtained based on the corrected characteristics of the variable attenuator. Therefore, even a variable attenuator having nonlinear characteristics can correct an output signal in a short time.

Further, the attenuation amount correction method of the present invention includes a signal generation unit that generates a test signal, a variable attenuator that attenuates the signal generated by the signal generation unit and whose characteristics change depending on temperature, and the variable attenuator. and a temperature detector for detecting the temperature around the variable attenuator. a step of determining characteristics of the attenuation amount with respect to a control parameter for controlling the attenuation amount of the variable attenuator based on the ambient temperature; obtaining the attenuation amount of the variable attenuator from the obtained signal level; and correcting the characteristic of the variable attenuator from the obtained attenuation amount and the predetermined value.

With this configuration, the characteristic corresponding to the ambient temperature of the variable attenuator is corrected by the signal level detected by the level detector when the control parameter is set to the predetermined value. Therefore, even if a device whose characteristics change with temperature is provided, the output signal can be corrected in a short period of time.

INDUSTRIAL APPLICABILITY The present invention can provide a signal generator capable of correcting an output signal in a short period of time even if it is equipped with equipment whose characteristics change with temperature.

FIG. 1 is a block diagram of a signal generator according to one embodiment of the present invention. FIG. 2 is a graph showing an example of characteristics of the variable attenuator of the signal generator according to one embodiment of the present invention. FIG. 3 is a flowchart for explaining the procedure of attenuation amount correction processing of the signal generator according to one embodiment of the present invention.

Hereinafter, signal generators according to embodiments of the present invention will be described in detail with reference to the drawings.

In FIG. 1, a signal generator 1 according to an embodiment of the present invention includes a signal generator 10 that generates a test signal, a variable attenuator 11 that attenuates the test signal generated by the signal generator 10, A level detector 12 for detecting the level of the test signal attenuated by the variable attenuator 11, an output port 13 for outputting the test signal attenuated by the variable attenuator 11, and a temperature around the variable attenuator 11 are measured. A temperature detection unit 14 for detecting temperature, a user interface unit 15 for accepting a user's operation and providing information to the user, and a control unit 16 for controlling each part of the device to execute processing as the signal generation device 1. consists of

The signal generation unit 10 is configured by a signal generator that generates test signals having the intensity and frequency set by the control unit 16 . The variable attenuator 11 is configured by, for example, a voltage control type variable attenuator. The variable attenuator 11 may be a digital control type variable attenuator.

The level detector 12 detects the level of the test signal attenuated by the variable attenuator 11 and outputs it to the controller 16 . The temperature detector 14 detects the temperature around the variable attenuator 11 and outputs it to the controller 16 .

The user interface unit 15 includes an input unit that receives an operation input from a user, and a display unit that displays a screen for setting parameters of test signals to be generated, various messages, and the like. The input unit is composed of a touch pad, keyboard, push buttons, rotary knob, and the like. The display unit is configured by a liquid crystal display device or the like.

The control unit 16 is configured by a computer unit including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk device, and an input/output port (not shown).

The ROM and hard disk device of the computer unit store programs for causing the computer unit to function as the control section 16 along with various control constants, various maps, and the like. That is, the computer unit functions as the control unit 16 by the CPU executing programs stored in the ROM and the hard disk device. The hard disk device may be a CF (Compact Flash) card based on flash memory.

The input/output ports of the controller 16 are connected to the signal generator 10, the variable attenuator 11, the level detector 12, the temperature detector 14, and the user interface 15, so that the controller 16 and each part can transmit and receive signals. It has become.

In this embodiment, the variable attenuator 11 has nonlinear characteristics as shown in FIG. Also, the variable attenuator 11 has different characteristics depending on the frequency of the signal to be attenuated. The figure shows the cases where the frequencies of the signals to be attenuated are 1.0 GHz, 5.0 GHz, and 7.0 GHz.

Also, the characteristics of the variable attenuator 11 change depending on the temperature of the variable attenuator 11 . The hard disk device of the control unit 16 stores, for example, the characteristics of the variable attenuator 11 for each predetermined temperature. The control unit 16 obtains the “basic characteristics” of the variable attenuator 11 based on the temperature around the variable attenuator 11 detected by the temperature detection unit 14 .

Based on the obtained "basic characteristics", the control unit 16 obtains a control voltage, which is a control parameter of the variable attenuator 11, such that a predetermined amount of attenuation, for example, 10 dB, is obtained. Sets the amount of attenuation for

The control unit 16 causes the signal generation unit 10 to generate a signal of a predetermined level, and detects the amount of attenuation by the variable attenuator 11 from the signal level detected by the level detection unit 12 .

The control unit 16 corrects the "basic characteristics" from the relationship between the detected attenuation amount and the control voltage. For example, the control unit 16 corrects the voltage value so that the control voltage value at the detected attenuation amount becomes the set voltage value. For example, the control unit 16 performs correction by moving the entire voltage value so that the value of the control voltage at the detected attenuation amount becomes the set voltage value.

The control unit 16 checks the control voltage for 25 dB of attenuation in 1 dB steps based on the "corrected characteristics". At this time, for example, in the case of the characteristics shown in FIG. 2, if the attenuation amount is less than 25 dB, the control voltage is rounded to zero [V]. Also, if the attenuation does not reach zero dB, the control voltage is rounded to 2.5[V].

Attenuation amount correction processing by the signal generator according to the present embodiment configured as described above will be described with reference to FIG. Note that the attenuation correction process described below is executed when the output level correction function is selected by operating the user interface unit 15 .

In step S1, the control unit 16 detects the temperature around the variable attenuator 11 by the temperature detection unit 14, and sets the characteristic map of the variable attenuator 11 corresponding to this temperature as the "basic characteristic" map. After executing the process of step S1, the control unit 16 executes the process of step S2.

In step S2, the control section 16 sets the control voltage of the variable attenuator 11 to a predetermined voltage, causes the signal generation section 10 to generate a signal of a predetermined level, and the level detection section 12 detects the level of the output signal. After executing the process of step S2, the control unit 16 executes the process of step S3.

In step S3, the control unit 16 obtains the attenuation amount of the variable attenuator 11 from the level of the detected output signal. After executing the process of step S3, the control unit 16 executes the process of step S4.

In step S4, the control unit 16 corrects the "basic characteristics" map from the obtained attenuation amount and the predetermined voltage set as the control voltage. After executing the process of step S4, the control unit 16 executes the process of step S5.

In step S5, the control unit 16 changes the control voltage based on the corrected map, and performs fine adjustment such as determining the control voltage corresponding to each 1 dB of attenuation. After executing the process of step S5, the control unit 16 ends the attenuation correction process.

As described above, in the above-described embodiment, the control unit 16 obtains the characteristics corresponding to the temperature around the variable attenuator 11, and the level detection unit 12 detects when the control voltage of the variable attenuator 11 is set to a predetermined voltage. The attenuation amount of the variable attenuator 11 is obtained from the signal level thus obtained, and the characteristic of the variable attenuator 11 is corrected from this attenuation amount and the predetermined voltage.

As a result, the characteristics corresponding to the temperature around the variable attenuator 11 are corrected by the signal level detected by the level detector 12 when the control voltage is set to the predetermined voltage. Therefore, even if a device whose characteristics change with temperature is provided, the output signal can be corrected in a short period of time.

Further, the control unit 16 performs adjustment to find a control voltage corresponding to the attenuation amount for each predetermined amount based on the corrected characteristics.

Thereby, the control voltage corresponding to the attenuation amount for each predetermined amount is obtained based on the corrected characteristics. Therefore, even the variable attenuator 11 having nonlinear characteristics can correct the output signal in a short time.

Although embodiments of the present invention have been disclosed, it will be apparent that modifications may be made by those skilled in the art without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

1 signal generator 10 signal generator 11 variable attenuator 12 level detector 14 temperature detector 16 controller

Claims (3)

a signal generator (10) for generating a test signal;
a variable attenuator (11) that attenuates the signal generated by the signal generator and whose characteristics change with temperature;
a level detector (12) for detecting the level of the signal attenuated by the variable attenuator;
a temperature detection unit (14) for detecting the temperature around the variable attenuator;
A characteristic of the attenuation amount with respect to a control parameter for controlling the attenuation amount of the variable attenuator is obtained based on the ambient temperature of the variable attenuator, and the level is detected when the control parameter of the variable attenuator is set to a predetermined value. a control section (16) for obtaining an attenuation amount of the variable attenuator from the signal level detected by the section, and correcting the characteristics of the variable attenuator from the obtained attenuation amount and the predetermined value. 2. The control unit according to claim 1, wherein the control unit performs adjustment to obtain the value of the control parameter corresponding to each predetermined amount of attenuation based on the corrected characteristic of the attenuation amount with respect to the control parameter of the variable attenuator. Signal generator. A signal generator (10) that generates a test signal, a variable attenuator (11) that attenuates the signal generated by the signal generator and whose characteristics change according to temperature, and a signal attenuated by the variable attenuator and a temperature detection unit (14) for detecting the temperature around the variable attenuator, comprising:
determining characteristics of the attenuation amount with respect to a control parameter for controlling the attenuation amount of the variable attenuator based on the ambient temperature of the variable attenuator;
obtaining an attenuation amount of the variable attenuator from the signal level detected by the level detector when the control parameter of the variable attenuator is set to a predetermined value;
and a step of correcting the characteristics of the variable attenuator from the obtained attenuation amount and the predetermined value.

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