Matrix switch for calibrating signal generator

Abstract

The invention discloses a matrix switch for signal generator calibration, which comprises a signal transmission module, a communication control module and a power supply module, and is characterized in that the signal transmission module is in communication connection with the communication control module, and the power supply module is electrically connected with the signal transmission module and the communication control module and supplies power to the signal transmission module and the communication control module; the signal transmission module comprises a radio-frequency signal switching sub-module, a low-frequency signal switching sub-module and a frequency synchronization sub-module; the radio frequency signal switching module is provided with two multi-channel coaxial change-over switches which are connected in series to form a multi-input multi-output matrix switch; the communication control module functionally realizes communication between the matrix switch and an automatic calibration program, sets a signal transmission channel according to an instruction of automatic calibration software, returns an operation result of the instruction to control software, responds to a state query instruction of the automatic calibration software and returns a working state of the current matrix switch; the power supply module supplies power to the matrix switch to ensure normal operation of the matrix switch.

Description

Technical Field

[0001] The present invention relates to the technical field of signal generator calibration, and in particular to a matrix switch for signal generator calibration. Background Art

[0002] The signal generator is a standard device that is widely used in many industries such as communications and electronics. The accuracy of its measurement value is very important. Calibration of the signal generator is an important method to ensure the accuracy of the signal generator's measurement value.

[0003] A signal generator is a precision, multi-parameter device. Current technical specifications specify 17 parameters for signal generator calibration. The higher the operating frequency band of the signal generator, the greater the amount of calibration data required for each parameter. Conventional manual calibration of signal generators is inefficient and time-consuming. Automatic calibration of signal generators is a key method for improving signal generator calibration efficiency. However, signal generator calibration requires nine different standard devices. Manually connecting cables when changing standards significantly reduces the efficiency of automatic calibration. Therefore, enabling the signal generator's output signal to automatically switch between inputs to different standard devices under the control of an automatic calibration program is key to achieving efficient automatic calibration of signal generators.

[0004] Matrix switches are devices that automatically switch programmable signal transmission channels. However, existing matrix switches are based on a general-purpose design and are not fully suitable for the automatic calibration process of signal generators. Manual operation of connecting cables cannot be completely avoided during use, further reducing calibration efficiency. There is an urgent need for an automatic switching device that can address the problems of the existing technology and further improve calibration efficiency. Summary of the Invention

[0005] The present invention provides a matrix switch for signal generator calibration. This matrix switch is designed based on current calibration specifications for various signal generators and is specifically designed for use in signal generator calibration. The switch meets the full parameter measurement requirements of standards such as JJF1931-2021 Signal Generator Calibration Specification, JJG 502-2017 Verification Procedure for Synthetic Signal Generators, and JJF 1174-2017 Vector Signal Generator Calibration Specification, enabling complete automatic calibration of these types of signal generators without the need for manual switching of connecting cables.

[0006] The technical solution adopted in the present invention is: A matrix switch for signal generator calibration, comprising a signal transmission module, a communication control module and a power supply module, wherein the signal transmission module is communicatively connected to the communication control module, and the power supply module is electrically connected to the signal transmission module and the communication control module to supply power to the signal transmission module and the communication control module; the signal transmission module comprises a radio frequency signal switching submodule, a low frequency signal switching submodule and a frequency synchronization submodule, wherein the radio frequency signal switching submodule, the low frequency signal switching submodule and the frequency synchronization submodule are independently and parallelly arranged; the periphery of the signal transmission module is configured with a plurality of fixed and calibrated coaxial cables and adapters; each calibrated input adapter is used to connect to the signal interface port of a different model of a calibrated signal generator ; Each calibrated output adapter is used to connect to a standard device for calibration; the communication control module is provided with four interfaces, and the communication interface of the control computer is matched through any one of the four interfaces; a storage module and a communication processor are provided in the communication control module, and the storage module stores the insertion loss data of each coaxial cable and each adapter, and the communication processor is provided with a response instruction function of the automatic calibration program; the communication control module is used to realize the communication between the matrix switch and the automatic calibration program, set the signal transmission channel according to the instruction of the automatic calibration program, and return the operation result of the instruction to the control program, and respond to the status query instruction of the automatic calibration program to return the current working status of the matrix switch.

[0007] The RF signal switching submodule is composed of two multi-channel coaxial switches connected in series. The input side of the first multi-channel coaxial switch is provided with 5 input channels. The input end of each input channel is connected to a 1.85mm (M)-1.85mm (M) coaxial cable, and the other ends of the four coaxial cables are respectively connected to 1.85mm (F)-N (M), 1.85mm (F)-3.5mm (M), 1.85mm (F)-2.92mm (M), and 1.85mm (F)-2.4mm (M) adapters; one input port of the five coaxial cables is used to adapt to one of the output ports of the calibrated signal generator; the output side of the first multi-channel coaxial switch is connected in series with the second multi-channel The input side of the first-channel coaxial conversion switch and the output side of the second multi-channel coaxial conversion switch are provided with 6 output channels. The output end of the first output channel is connected to a 1.85mm (F)-BNC (M) coaxial cable, and the second output channel to the sixth output channel are all connected to 1.85mm (M)-1.85mm (M) coaxial cables. The output ends of the first output channel and the second output channel are used to connect to the high-frequency frequency measurement channels of CH1 and CH2 of the counter; the output end of the third output channel is used to connect to the input end of the power meter; the output end of the fourth output channel is used to connect to the input end of the spectrum analyzer; the output end of the fifth output channel is used to connect to the input end of the measuring receiver; and the output end of the sixth output channel is used to connect to the input end of the oscilloscope.

[0008] The low-frequency signal switching submodule is equipped with an input channel and two output channels. The input channel is connected to a BNC (M)-BNC (M) coaxial cable and is used for the output end of the built-in low-frequency signal source signal of the calibrated signal generator; the first output channel is connected to a BNC (M)-BNC (M) coaxial cable and is used to connect to a counter; the second output channel is connected to a BNC (M)-Banana (M) coaxial cable and is used to connect to a digital multimeter.

[0009] The frequency synchronization submodule is provided with one input channel and two output channels. The input channel is connected to a BNC (M)-BNC (M) coaxial cable. The input end of the input channel is used to connect to the reference frequency output signal end of the calibrated signal generator; the two output channels are both connected to a BNC (M)-BNC (M) coaxial cable. The output end of the first output channel is connected to the reference frequency input end of the spectrum analyzer; the output end of the second output channel is connected to the frequency standard comparator to measure the reference frequency output signal of the signal generator; when the frequencies of two devices need to be synchronized, the output end of the frequency synchronization submodule channel is opened. When the output end of the frequency synchronization submodule is closed, the frequencies of the two devices are no longer synchronized.

[0010] The four interfaces of the communication control module include USB, RS-232, RJ45 and GPIB4 interfaces.

[0011] The storage module stores the insertion loss data of each coaxial cable and each adapter, that is, the insertion loss value of each channel in the full frequency range is stored. The insertion loss value of the specified channel at the specified frequency is queried through instructions, and then the measured value is corrected.

[0012] The matrix switch of the present invention primarily comprises three modules: a signal transmission module, a communication control module, and a power supply module. The signal transmission module consists of a radio frequency signal switching submodule, a low-frequency signal switching submodule, and a frequency synchronization submodule. The operating frequency bands of these three modules cover the output signals of the calibrated signal generator, from low to high frequencies. The three submodules are independent of each other and can be controlled to operate simultaneously. A failure in one module does not affect the normal operation of the other modules. When the calibrated signal generator supports simultaneous output of radio frequency signals and a built-in low-frequency source, the radio frequency signal switching submodule and the low-frequency signal switching submodule can be controlled to operate simultaneously, further improving the efficiency of automatic calibration.

[0013] The matrix switch also features internal memory that stores insertion loss values for each channel across the full frequency range. Commands can be used to query the insertion loss value for a specific channel at a specific frequency, allowing for corrections to be made to improve measurement accuracy. The stored insertion loss values include not only the insertion loss of each channel within the matrix switch itself, but also the insertion loss of the coaxial cables and adapters used to connect that channel. If the coaxial cables and adapters used for each channel are replaced, the new insertion loss values can be written to the memory via a command for subsequent use, ensuring measurement accuracy throughout the system is maintained regardless of cable and adapter changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a circuit principle block diagram of the present invention. DETAILED DESCRIPTION

[0015] like Figure 1 As shown, the present invention includes a matrix switch for signal generator calibration, including a signal transmission module, a communication control module and a power supply module, the signal transmission module is communicatively connected to the communication control module, the power supply module is electrically connected to the signal transmission module and the communication control module, and supplies power to the signal transmission module and the communication control module; the signal transmission module includes a radio frequency signal switching submodule, a low frequency signal switching submodule and a frequency synchronization submodule, and the radio frequency signal switching submodule, the low frequency signal switching submodule and the frequency synchronization submodule are independently and parallelly arranged; the periphery of the signal transmission module is configured with a plurality of fixed and calibrated coaxial cables and adapters; each calibrated input adapter is used to connect to the signal interface end of the calibrated signal generator of different models; each calibrated output adapter is used to connect to the signal interface end of the calibrated signal generator of different models; The head is used to connect standard equipment for calibration; the communication control module is provided with four interfaces, including USB, RS-232, RJ45, and GPIB4 interfaces, and the communication interface of the control computer is matched through any one of the four interfaces; a storage module and a communication processor are provided in the communication control module, the storage module stores the insertion loss data of each coaxial cable and each adapter, and the communication processor has a response instruction function of the automatic calibration program; the communication control module is used to realize the communication between the matrix switch and the automatic calibration program, set the signal transmission channel according to the instruction of the automatic calibration program, return the operation result of the instruction to the control program, and respond to the status query instruction of the automatic calibration program to return the current working status of the matrix switch.

[0016] The communication control module functionally enables communication between the matrix switch and the automatic calibration program. It sets the signal transmission channel according to the instructions of the automatic calibration software, returns the results of the instructions to the control software, and responds to the status query instructions of the automatic calibration software to return the current operating status of the matrix switch. The module stores the insertion loss data of each channel of the RF switch. This insertion loss data includes the insertion loss of the signal channel within the matrix switch and the insertion loss of the coaxial cable and adapter connected to the channel. The control software can query the insertion loss data of the current signal transmission channel through instructions and automatically correct the signal value in the measurement results. After the matrix switch is calibrated, the insertion loss data of each channel can be written to the communication control module of the matrix switch through instructions for easy use in subsequent calibrations. If the coaxial cable or adapter used in the signal channel is replaced, the stored data can be updated using instructions.

[0017] The RF signal switching submodule is composed of two multi-channel coaxial switches connected in series. The input side of the first multi-channel coaxial switch is provided with 5 input channels. The input end of each input channel is connected to a 1.85mm (M)-1.85mm (M) coaxial cable, and the other ends of the four coaxial cables are respectively connected to 1.85mm (F)-N (M), 1.85mm (F)-3.5mm (M), 1.85mm (F)-2.92mm (M), and 1.85mm (F)-2.4mm (M) adapters; one input port of the five coaxial cables is used to adapt to one of the output ports of the calibrated signal generator; the output side of the first multi-channel coaxial switch is connected in series with the second multi-channel The input side of the first-channel coaxial conversion switch and the output side of the second multi-channel coaxial conversion switch are provided with 6 output channels. The output end of the first output channel is connected to a 1.85mm (F)-BNC (M) coaxial cable, and the second output channel to the sixth output channel are all connected to 1.85mm (M)-1.85mm (M) coaxial cables. The output ends of the first output channel and the second output channel are used to connect to the high-frequency frequency measurement channels of CH1 and CH2 of the counter; the output end of the third output channel is used to connect to the input end of the power meter; the output end of the fourth output channel is used to connect to the input end of the spectrum analyzer; the output end of the fifth output channel is used to connect to the input end of the measuring receiver; and the output end of the sixth output channel is used to connect to the input end of the oscilloscope.

[0018] The low-frequency signal switching submodule is equipped with an input channel and two output channels. The input channel is connected to a BNC (M)-BNC (M) coaxial cable and is used for the output end of the built-in low-frequency signal source signal of the calibrated signal generator; the first output channel is connected to a BNC (M)-BNC (M) coaxial cable and is used to connect to a counter; the second output channel is connected to a BNC (M)-Banana (M) coaxial cable and is used to connect to a digital multimeter.

[0019] The frequency synchronization submodule is provided with one input channel and two output channels. The input channel is connected to a BNC (M)-BNC (M) coaxial cable. The input end of the input channel is used to connect to the reference frequency output signal end of the calibrated signal generator; the two output channels are both connected to a BNC (M)-BNC (M) coaxial cable. The output end of the first output channel is connected to the reference frequency input end of the spectrum analyzer; the output end of the second output channel is connected to the frequency standard comparator to measure the reference frequency output signal of the signal generator; when the frequencies of two devices need to be synchronized, the output end of the frequency synchronization submodule channel is opened. When the output end of the frequency synchronization submodule is closed, the frequencies of the two devices are no longer synchronized.

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] For example, if a 50 GHz signal generator with a 2.4 mm (f) RF output port needs to be automatically calibrated using the RF switch of the present invention in accordance with the JJF 1931-2021 Signal Generator Calibration Specification, a computer must first be connected to the communication control module of the matrix switch to input control commands.

[0022] The signal generator's RF output port is connected to the 2.4mm (m) input port of the matrix switch's RF signal switching submodule. The internal modulation generator's output interface is connected to the low-frequency signal switching submodule's input interface. The reference frequency output interface is connected to the frequency synchronization submodule's input interface. Output Channel 1 of the matrix switch's RF signal switching submodule is connected to a counter's CH1 channel, Output Channel 2 is connected to a counter's CH3 channel, Output Channel 3 is connected to a power meter / power sensor, Output Channel 4 is connected to a spectrum analyzer, Output Channel 5 is connected to a measurement receiver, and Output Channel 6 is connected to an oscilloscope. Output Channel 1 (BNC connector channel) of the matrix switch's low-frequency signal switching submodule is connected to a counter's CH2 channel, and Output Channel 2 (Banana connector) of the low-frequency signal switching submodule is connected to a digital multimeter. The output interface of the matrix switch's frequency synchronization submodule is connected to the reference frequency input interface of the spectrum analyzer.

[0023] When calibrating according to specifications and measuring different parameters, set the corresponding connection channels of the matrix switch according to the standard instruments used, and turn off the unused output channels. Then, different standard equipment can be used to measure the output signal of the signal generator.

[0024] 1. When measuring frequency parameters, input instructions through the computer to enable output channel 1 of the matrix switch RF signal switching submodule, disable other output channels of the RF switch, and use the counter's CH1 channel to measure the frequency. When the signal generator's output signal frequency exceeds 300MHz, enable output channel 2 of the matrix switch RF signal switching submodule, disable other output channels, and use the counter's CH3 channel to measure the frequency. 2. When measuring power parameters, when the output power of the signal generator is between -20dBm and +30dBm, input instructions into the computer to select output channel 3 of the matrix switch RF signal switching submodule and use a power meter to measure the power of the signal generator output signal. When the output signal is less than -20dBm, select output channel 5 of the matrix switch RF signal switching submodule and use a measuring receiver to measure the output signal power of the signal generator. 3. When measuring the carrier residual amplitude modulation and carrier residual frequency modulation parameters, input instructions through the computer to select the output channel 5 of the matrix switch RF signal switching submodule and use the measurement receiver to perform the measurement; 4. When measuring harmonic, non-harmonic, and single-sideband phase noise parameters, input instructions through the computer to select the output channel 4 of the matrix switch RF signal switching submodule and the signal channel of the frequency synchronization submodule, and use a spectrum analyzer for measurement; 5. When measuring parameters such as AM depth, FM deviation, PM deviation, modulation and demodulation distortion, FM under amplitude modulation, and AM under frequency modulation, input commands via a computer to select output channel 5 of the matrix switch RF signal switching submodule and perform measurements using a measurement receiver. 6. When measuring the pulse modulation on-off ratio, input instructions through the computer to select the output channel 4 of the matrix switch RF signal switching submodule and use a frequency analyzer to measure; 7. When measuring the pulse modulation rise / fall time parameters, input instructions through the computer to select the output channel 6 of the matrix switch RF signal switching submodule and use an oscilloscope to measure; 8. When measuring the frequency of the internal modulation generator, open the low-frequency signal switching module output channel 1 and use the counter's CH2 channel for measurement; 9. To measure the amplitude of the internal modulation generator, enter a command on the computer to open output channel 2 of the low-frequency signal switching module and use a digital multimeter to measure. When the calibrated signal generator supports simultaneous output of the RF signal and the internal modulation generator, the matrix switch supports simultaneous measurement of the RF signal and the internal modulation generator output signal, that is, measurements 8 to 9 are performed simultaneously with measurements 1 to 7.

[0025] During each measurement and port interface switching process, the computer can query the insertion loss value of a specified channel at a specified frequency through commands, correct the measured value, and improve measurement accuracy. This processing method is conventional in computer processing and belongs to the existing technology, so it will not be described in detail here; however, this processing method has no application in matrix switches.

[0026] When calibrating this signal generator according to JJG 502-2017, Verification Procedure for Synthetic Signal Generators, the second output channel of the frequency synchronization submodule was connected to a frequency standard comparator. The connection method for the remaining channels was the same as when calibrating according to JJF 1931-2021, Signal Generator Calibration Specification. During calibration, when measuring the internal timebase, the second output channel of the matrix switch frequency synchronization submodule was enabled, while the other channels were disabled. When measuring attenuation (relative level parameters), output channel 6 of the RF signal switching submodule in the RF switch was enabled, while the other output channels were disabled, and measurements were taken using a measurement receiver. The procedure for measuring other parameters was the same as when calibrating according to JJF 1931-2021, Signal Generator Calibration Specification. When calibrating a vector signal generator according to JJF 1174-2017, Vector Signal Generator Calibration Specifications, the instrument connections are the same as when calibrating according to JJG 502-2017, Verification Procedure for Synthetic Signal Generators. When measuring vector modulation parameters, enable output channel 6 of the RF signal switching submodule in the RF switch, disable all other output channels, and use a measurement receiver for measurement. The measurement process for other parameters is the same as when calibrating according to JJF 1931-2021, Signal Generator Calibration Specifications, and JJG 502-2017, Verification Procedure for Synthetic Signal Generators.

[0027] This matrix switch meets the full parameter measurement requirements of JJF 1931-2021 Signal Generator Calibration Specification, JJG 502-2017 Synthetic Signal Generator Verification Procedure, JJF 1174-2017 Vector Signal Generator Calibration Specification, etc., and realizes complete automatic calibration of these types of signal generators, eliminating the need for manual switching of connecting cables during the automatic calibration process.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A matrix switch for signal generator calibration, characterized in that: It includes a signal transmission module, a communication control module and a power supply module. The signal transmission module is communicatively connected to the communication control module. The power supply module is electrically connected to the signal transmission module and the communication control module to supply power to the signal transmission module and the communication control module. The signal transmission module includes a radio frequency signal switching submodule, a low frequency signal switching submodule and a frequency synchronization submodule. The radio frequency signal switching submodule, the low frequency signal switching submodule and the frequency synchronization submodule are independently and parallelly arranged. The periphery of the signal transmission module is configured with a plurality of fixed and calibrated coaxial cables and adapters. Each calibrated input adapter is used to connect the signal interface end of the calibrated signal generator of different models. Each calibrated The output adapter is used to connect to standard equipment for calibration; the communication control module is provided with four interfaces, and any one of the four interfaces is matched to the communication interface of the control computer; the communication control module is provided with a storage module and a communication processor, the storage module stores the insertion loss data of each coaxial cable and each adapter, and the communication processor has a response instruction function of the automatic calibration program; the communication control module is used to realize communication between the matrix switch and the automatic calibration program, set the signal transmission channel according to the instruction of the automatic calibration program, return the operation result of the instruction to the control program, and respond to the status query instruction of the automatic calibration program to return the current working status of the matrix switch.

2. The signal generator calibration matrix switch according to claim 1, wherein: The RF signal switching submodule is composed of two multi-channel coaxial switches connected in series. The input side of the first multi-channel coaxial switch is provided with 5 input channels. The input end of each input channel is connected to a 1.85mm (M)-1.85mm (M) coaxial cable, and the other ends of the four coaxial cables are respectively connected to 1.85mm (F)-N (M), 1.85mm (F)-3.5mm (M), 1.85mm (F)-2.92mm (M), and 1.85mm (F)-2.4mm (M) adapters; one input port of the five coaxial cables is used to adapt to one of the output ports of the calibrated signal generator; the output side of the first multi-channel coaxial switch is connected in series with the second multi-channel The input side of the first-channel coaxial conversion switch and the output side of the second multi-channel coaxial conversion switch are provided with 6 output channels. The output end of the first output channel is connected to a 1.85mm (F)-BNC (M) coaxial cable, and the second output channel to the sixth output channel are all connected to 1.85mm (M)-1.85mm (M) coaxial cables. The output ends of the first output channel and the second output channel are used to connect to the high-frequency frequency measurement channels of CH1 and CH2 of the counter; the output end of the third output channel is used to connect to the input end of the power meter; the output end of the fourth output channel is used to connect to the input end of the spectrum analyzer; the output end of the fifth output channel is used to connect to the input end of the measuring receiver; and the output end of the sixth output channel is used to connect to the input end of the oscilloscope.

3. The signal generator calibration matrix switch according to claim 2, wherein: The low-frequency signal switching submodule is equipped with an input channel and two output channels. The input channel is connected to a BNC (M)-BNC (M) coaxial cable and is used for the output end of the built-in low-frequency signal source signal of the calibrated signal generator; the first output channel is connected to a BNC (M)-BNC (M) coaxial cable and is used to connect to a counter; the second output channel is connected to a BNC (M)-Banana (M) coaxial cable and is used to connect to a digital multimeter.

4. The signal generator calibration matrix switch according to claim 3, wherein: The frequency synchronization submodule is provided with one input channel and two output channels. The input channel is connected to a BNC (M)-BNC (M) coaxial cable. The input end of the input channel is used to connect to the reference frequency output signal end of the calibrated signal generator; the two output channels are both connected to a BNC (M)-BNC (M) coaxial cable. The output end of the first output channel is connected to the reference frequency input end of the spectrum analyzer; the output end of the second output channel is connected to the frequency standard comparator to measure the reference frequency output signal of the signal generator; when the frequencies of two devices need to be synchronized, the output end of the frequency synchronization submodule channel is opened. When the output end of the frequency synchronization submodule is closed, the frequencies of the two devices are no longer synchronized.

5. The signal generator calibration matrix switch according to claim 1, wherein: The four interfaces of the communication control module include USB, RS-232, RJ45 and GPIB4 interfaces.

6. The signal generator calibration matrix switch according to claim 1, wherein: The storage module stores the insertion loss data of each coaxial cable and each adapter, that is, the insertion loss value of each channel in the full frequency range is stored. The insertion loss value of the specified channel at the specified frequency is queried through instructions, and then the measured value is corrected.

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