A vector network analyzer system of a no-reference channel circuit single receiver architecture

Abstract

The application discloses a kind of vector network analyzer systems of single receiver architecture of no reference channel circuit, belong to electronic measurement and data acquisition and analysis technical field, including radio frequency transmitting module, radio frequency receiving module, for generating LO local oscillator signal local oscillator source output module.The application adopts correlation double sampling mode, suppresses the direct current component of receiver, and the ability of direct current component suppression is higher than traditional digital IQ down conversion, with the ability of improving the final measurement accuracy of vector network analyzer;By using analog phase transformation circuit, without increasing reference signal hardware channel circuit again, digital control oscillator and digital IQ down conversion function are omitted, IQ data calculation amount is reduced, and hardware resources are also saved;Since only one way ADC is used for sampling, i.e.single receiver architecture is used, system cost is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of electronic measurement and data acquisition and analysis technology, specifically to a vector network analyzer system with a single receiver architecture and no reference channel circuit. Background Technology

[0002] In the field of radio frequency (RF) and microwave measurement, vector network analyzers are used to characterize RF devices. Although initially used only for measuring S-parameters, modern vector network analyzers are highly integrated and advanced to outperform the device under test. RF circuits require unique testing methods. It is difficult to directly measure voltage and current at high frequencies; therefore, when measuring high-frequency devices, they must be characterized by their response to RF signals. Vector network analyzers characterize the device by sending a known signal to the device and then performing a ratio measurement on the input and output signals.

[0003] Early network analyzers only measured amplitude. These scalar network analyzers could measure return loss, gain, VSWR, and perform other amplitude-based measurements. Today, most network analyzers are vector network analyzers, capable of measuring both amplitude and phase simultaneously. Vector network analyzers are a very versatile class of instruments; they can characterize S-parameters, match complex impedances, and perform time-domain measurements.

[0004] Traditional intermediate frequency data processing requires a large amount of hardware resources. Moreover, with the same amount of hardware resources, the filtering effect of interference signals is difficult to guarantee because the rectangular coefficient of digital filters is very small and the transition band is smooth and not steep. Digital filters occupy a lot of resources, while analog filters are large in size and occupy a lot of space, and are relatively complicated to debug. The above problems need to be solved. To this end, a vector network analyzer system with a single receiver architecture without reference channel circuit is proposed. Summary of the Invention

[0005] The technical problem to be solved by this invention is: how to solve the problems of high complexity of system hardware design and difficulty of debugging the radio frequency front end in the prior art. It provides a vector network analyzer system with a single receiver architecture without reference channel circuit, which significantly reduces the complexity of system hardware design and the difficulty of debugging the radio frequency front end.

[0006] The present invention solves the above-mentioned technical problems through the following technical solution: The present invention includes an RF transmitting module, an RF receiving module, and a local oscillator source output module for generating LO local oscillator signals; the RF transmitting module has two output terminals connected to two corresponding input terminals of the RF receiving module, and one output terminal of the RF transmitting module is connected to one output terminal of the local oscillator source output module, through which the RF transmitting module transmits RF signals; the RF receiving module also has one input terminal connected to another output terminal of the local oscillator source output module, through which the RF receiving module receives RF signals and performs intermediate frequency signal data acquisition.

[0007] Furthermore, the RF transmitting module includes a first integrated phase-locked loop frequency synthesizer, a balun, a first wideband 2-to-1 switch, a first bandpass filter, a 90-degree bridge, a second wideband 2-to-1 switch, a second bandpass filter, a first mixer, a channel filter bank, an amplifier, a step attenuator, a directional coupler, and a transmit output port; one differential output of the first integrated phase-locked loop frequency synthesizer is connected to the input of the balun, the output of the balun is connected to the input of the first wideband 2-to-1 switch, the output of the first wideband 2-to-1 switch is connected to the input of the first bandpass filter, and the first bandpass filter output... The output terminal is connected to the input terminal of the second broadband 2-to-1 switch via a 90-degree bridge. The output terminal of the second broadband 2-to-1 switch is connected to the input terminal of the second bandpass filter. The output terminal of the second bandpass filter is connected to the intermediate frequency input terminal of the first mixer. The RF output terminal of the first mixer is connected to the input terminal of the channel filter bank. The output terminal of the channel filter bank is connected to the input terminal of the amplifier. The output terminal of the amplifier is connected to the input terminal of the step attenuator. The output terminal of the step attenuator is connected to the input terminal of the directional coupler. One of the output terminals of the directional coupler is connected to the transmit output port for outputting a variable amplitude RF signal.

[0008] Furthermore, the RF receiving module includes a receiving input port, a third broadband 2-to-1 switch, a fourth broadband 2-to-1 switch, a fixed attenuator, a second mixer, a third bandpass filter, a low-pass filter, and an ADC sampling unit. The input terminal of the third broadband 2-to-1 switch is connected to the coupling output terminal of the directional coupler. The input terminal of the fourth broadband 2-to-1 switch is connected to both the output terminal of the third broadband 2-to-1 switch and the receiving input port. The output terminal of the fourth broadband 2-to-1 switch is connected to the input terminal of the fixed attenuator. The output terminal of the fixed attenuator is connected to the RF input terminal of the second mixer. The intermediate frequency output terminal of the second mixer is connected to the input terminal of the third bandpass filter. The output terminal of the third bandpass filter is connected to the RF input terminal of the third mixer. The intermediate frequency output terminal of the third mixer is connected to the input terminal of the low-pass filter. The output terminal of the low-pass filter is connected to the input terminal of the ADC sampling unit. Another output terminal of the first integrated phase-locked loop frequency synthesizer is connected to the local oscillator input terminal of the third mixer.

[0009] Furthermore, the local oscillator output module is a second integrated phase-locked loop frequency synthesizer, and the two output terminals of the second integrated phase-locked loop frequency synthesizer are respectively connected to the local oscillator input terminal of the first mixer and the local oscillator input terminal of the second mixer.

[0010] Furthermore, the first integrated phase-locked loop frequency synthesizer generates a point frequency signal cos(ω0t). By controlling the channel switching of the first wideband two-to-one switch and the second wideband two-to-one switch, it can combine RF signals with phases of 0 degrees, 90 degrees, 180 degrees and 270 degrees, namely four phase signals: cos(ω0t), cos(ω0t+pi / 2), cos(ω0t+pi), and cos(ω0t+3×pi / 2).

[0011] Furthermore, when the vector network analyzer system performs S11 parameter measurement, it controls the third and fourth broadband two-to-one switches to import the coupled output signal of the directional coupler into the radio frequency receiving module. The S11 parameter can then be measured by digital sampling through the ADC sampling unit.

[0012] Furthermore, when the vector network analyzer system performs S21 parameter measurement, the coupling output signal of the directional coupler is connected to a 50-ohm resistor by controlling the third broadband two-to-one switch, and the input RF video signal of the receiving input port is imported into the radio frequency receiving module by controlling the fourth broadband two-to-one switch, thus realizing the measurement of S21 parameter.

[0013] Compared with the prior art, the present invention has the following advantages: This vector network analyzer system with a single receiver architecture and no reference channel circuit, due to the use of correlated double sampling, suppresses the DC component of the receiver. Its ability to suppress the DC component is higher than that of traditional digital IQ downconversion, thus improving the final measurement accuracy of the vector network analyzer; by using an analog phase conversion circuit, there is no need to add a reference signal hardware channel circuit, omitting the digital control oscillator and digital IQ downconversion function, reducing the computational load of generating IQ data, and also saving hardware resources; since only one ADC is used for sampling, i.e., a single receiver architecture is adopted, the system cost is greatly reduced. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the vector network analyzer system under parameter measurement state in S11 of the embodiment of the present invention, which features a single receiver architecture without a reference channel circuit.

[0015] Figure 2 This is a schematic diagram of the signal phase control timing and ADC sampling unit process of the hardware circuit in an embodiment of the present invention;

[0016] Figure 3This is a schematic diagram of the structure of a vector network analyzer system with a single receiver architecture and no reference channel circuit in the S21 parameter measurement state in an embodiment of the present invention.

[0017] Figure 1 , 3 In the middle section: 101, First integrated phase-locked loop frequency synthesizer; 102, Balun; 103, First wideband 2-to-1 switch; 104, First bandpass filter; 105, 50-ohm resistor; 106, 90-degree bridge; 107, Second wideband 2-to-1 switch; 108, Second bandpass filter; 109, First mixer; 110, Channel filter bank; 111, Amplifier; 112, Step attenuator; 113, Directional coupler; 114, Transmit output port; 115, Receive input port; 116, Third wideband 2-to-1 switch; 117, 50-ohm resistor; 118, Fourth wideband 2-to-1 switch; 119, Fixed attenuator; 120, Second integrated phase-locked loop frequency synthesizer; 121, Second mixer; 122, Third bandpass filter; 123, Third mixer; 124, Low-pass filter; 125, ADC sampling unit. Detailed Implementation

[0018] The embodiments of the present invention are described in detail below. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0019] like Figure 1 As shown, this embodiment provides a technical solution: a vector network analyzer system with a single receiver architecture without a reference channel circuit, including module 1, module 2, and module 3, wherein module 1 is an RF transmitting module, module 2 is an RF receiving module, and module 3 is a local oscillator output module.

[0020] The radio frequency (RF) transmitting module has two output terminals connected to the input terminals of the RF receiving module, and one input terminal connected to the output terminal of the local oscillator output module, for transmitting RF signals.

[0021] The radio frequency receiving module has two input terminals connected to the output terminal of the radio frequency transmitting module, and another input terminal connected to the output terminal of the local oscillator output module. It is used to receive RF radio frequency signals and perform intermediate frequency signal data acquisition.

[0022] The two output terminals of the local oscillator output module are connected to the input terminals of the RF transmitting module and the RF receiving module, respectively, to generate the LO local oscillator signal.

[0023] The radio frequency transmission module includes a first integrated phase-locked loop frequency synthesizer 101, a balun 102, a first broadband two-to-one switch 103, a first bandpass filter 104, a 50-ohm resistor 105, a 90-degree bridge 106, a second broadband two-to-one switch 107, a second bandpass filter 108, a first mixer 109, a channel filter bank 110, an amplifier 111, a step attenuator 112, a directional coupler 113, and a transmit output port 114.

[0024] The radio frequency receiving module includes a receiver input port 115, a third wideband two-to-one switch 116, a 50-ohm resistor 117, a fourth wideband two-to-one switch 118, a fixed attenuator 119, a second mixer 121, a third bandpass filter 122, a third mixer 123, a low-pass filter 124, and an ADC sampling unit 125.

[0025] The local oscillator output module is the second integrated phase-locked loop frequency synthesizer 120.

[0026] The specific connection relationships of the various parts in the radio frequency transmission module are as follows:

[0027] A first integrated phase-locked loop frequency synthesizer 101 has one differential output connected to the input of a balun 102, and the output of the balun 102 connected to the input of a first wideband 2-to-1 switch 103, used to generate radio frequency output signals with phases of 0 degrees, 90 degrees, 180 degrees, and 270 degrees; another output of the first integrated phase-locked loop frequency synthesizer 101 is connected to the local oscillator input of a third mixer 123, used to generate an intermediate frequency signal to facilitate digital sampling by the ADC chip (ADC sampling unit 125).

[0028] A first broadband 2-to-1 switch 103 is connected to the input of a first bandpass filter 104. The output of the first bandpass filter 104 is connected to the input of a second broadband 2-to-1 switch 107 via a 90-degree bridge 106. The output of the second broadband 2-to-1 switch 107 is connected to the input of a second bandpass filter 108. The output of the second bandpass filter 108 is connected to the intermediate frequency input of a first mixer 109. The RF output of the first mixer 109 is connected to the input of a channel filter bank 110. The output of the channel filter bank 110 is connected to the input of an amplifier 111. By filtering the broadband RF signal output by the first mixer 109, a clean frequency-variable RF output signal is generated.

[0029] Amplifier 111, the output of which is connected to the input of step attenuator 112, the output of which is connected to the input of directional coupler 113, and one of the outputs of directional coupler 113 is connected to transmit output port 114, for outputting RF radio frequency output signals with variable signal amplitude.

[0030] The specific connection relationships of the various parts in the radio frequency receiving module are as follows:

[0031] The third broadband two-to-one switch 116 has its input terminal connected to the coupling output terminal of the directional coupler 113, and is used to receive the reflected signal from the transmit output port 114 (the RF output signal emitted by the transmit output port 114 will be reflected due to impedance mismatch, and the reflected signal will be output through the coupling output terminal of the directional coupler 113).

[0032] The fourth broadband 2-to-1 switch 118 has its input terminal connected to the output terminal of the third broadband 2-to-1 switch 116 and the receiving input port 115, respectively, and is used to switch the input signal source.

[0033] A fourth broadband 2-to-1 switch 118 is provided. The output of the fourth broadband 2-to-1 switch 118 is connected to the input of a fixed attenuator 119. The output of the fixed attenuator 119 is connected to the RF input of a second mixer 121. The intermediate frequency output of the second mixer 121 is connected to the input of a third bandpass filter 122. The output of the third bandpass filter 122 is connected to the RF input of a third mixer 123. The intermediate frequency output of the third mixer 123 is connected to the input of a low-pass filter 124. The output of the low-pass filter 124 is connected to the input of an ADC sampling unit 125. This is used to sample the input RF signal.

[0034] The specific connection relationships of the various parts in the radio frequency receiving module are as follows:

[0035] The second integrated phase-locked loop frequency synthesizer 120 has two output terminals connected to the local oscillator input terminal of the first mixer 109 and the local oscillator input terminal of the second mixer 121, respectively, for up-conversion of the RF transmitting module and down-conversion of the RF receiving module.

[0036] The specific implementation process of the function of this invention is as follows:

[0037] 1. The first integrated phase-locked loop frequency synthesizer 101 generates a point frequency signal cos(ω0t). By controlling the channel switching of the first wideband two-to-one switch 103 and the second wideband two-to-one switch 107, radio frequency output signals with phases of 0 degrees, 90 degrees, 180 degrees and 270 degrees can be combined, namely four phase signals: cos(ω0t), cos(ω0t+pi / 2), cos(ω0t+pi), and cos(ω0t+3×pi / 2).

[0038] 2. Adjusting the amplitude of the RF output signal by stepping attenuator 112 can improve the dynamic range of the vector network analyzer system.

[0039] 3. When this vector network analyzer system performs S11 parameter measurement, it is only necessary to control the third broadband two-to-one switch 116 and the fourth broadband two-to-one switch 118 to import the coupled output signal of the directional coupler 113 into the radio frequency receiving module 2, and then perform digital sampling through the ADC sampling unit 125 to realize the measurement of S11 parameters.

[0040] 4. The RF receiving module 2 performs two down-conversions on the received RF signal. The RF input signal is signal1, i.e., cos(ω0t+θ0), and the signal generated by the second integrated phase-locked loop frequency synthesizer 120 is signal2, i.e., cos(ω1t+θ1). After passing through the second mixer 121, the signal undergoes the first down-conversion.

[0041] signal1×signal2=cos(ω0t+θ0)×cos(ω1t+θ1)

[0042]

[0043] The IF1 signal, i.e., cos(ω0t-ω1t+θ0-θ1), can be obtained by filtering out the high-frequency signal through the third bandpass filter 122.

[0044] The signal generated by the first integrated phase-locked loop frequency synthesizer 101 is signal3, i.e., cos(ω2t+θ2), where ω2=ω0-ω1. After passing through the third mixer 123, it undergoes a second down-conversion.

[0045] IF1×signal3=cos(ω0t-ω1t+θ0-θ1)×cos(ω2t+θ2)

[0046]

[0047] Since ω2=ω0-ω1, we get:

[0048]

[0049] The IF2 signal, i.e., cos(θ0-θ1-θ2), can be obtained by filtering out high-frequency signals using low-pass filter 124.

[0050] 5. Since the IF2 signal is a DC signal, the state of the RF input signal of the RF receiving module 2 can be obtained by sampling the IF2 signal through the ADC sampling unit 125; through the output combination of the balun 102 and the 90-degree bridge 106, 0-degree, 90-degree, 180-degree, and 270-degree signals can be generated. The ADC sampling unit 125 samples at times t01, t11, t21, and t31 respectively, and can obtain the DC voltage values ​​VA, VB, VC, and VD respectively. Figure 2 As shown. The control signal only needs to ensure that the time intervals t0~t01, t1~t11, t2~t21, and t3~t31 are equal to achieve a correlation between the DC voltage values ​​VA, VB, VC, and VD, thus yielding:

[0051] Amplitude of S11 signal:

[0052] Phase of the S11 signal: Or obtain the complex format of the S11 signal.

[0053] 6. Similarly, by controlling the third broadband two-to-one switch 116 to select and connect the coupled output signal of the directional coupler 113 to the 50-ohm resistor 117, and by controlling the fourth broadband two-to-one switch 118 to import the input signal of the receiving input port 115 into the RF receiving module 3, the measurement of the S21 parameter can be realized. Figure 3 As shown.

[0054] Related dual sampling method: Data is acquired from the first integrated phase-locked loop frequency synthesizer of the RF transmitting module and the RF receiving module. This sampled data is obtained through time-division sampling and switching of the corresponding hardware phase states, resulting in a set of sampled data under four phase states, such as... Figure 2 As shown, this is the time-division sampling process.

[0055] It should be noted that steps 4 and 5 above describe the workflow and formula derivation of the relevant double sampling method.

[0056] In summary, the vector network analyzer system with a single receiver architecture and no reference channel circuit described in the above embodiments, due to its use of correlated double sampling, suppresses the DC component of the receiver. Its ability to suppress the DC component is higher than that of traditional digital IQ down-conversion, thus improving the final measurement accuracy of the vector network analyzer. By using an analog phase conversion circuit, there is no need to add a reference signal hardware channel circuit, eliminating the need for a digitally controlled oscillator and digital IQ down-conversion function, reducing the computational load for generating IQ data, and saving hardware resources. Since only one ADC is used for sampling, i.e., a single receiver architecture, the system cost is greatly reduced.

[0057] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A vector network analyzer system with a single receiver architecture and no reference channel circuit, characterized in that, include: RF transmitting module, RF receiving module, and local oscillator source output module for generating LO local oscillator signal; The radio frequency (RF) transmitting module has two output terminals connected to two corresponding input terminals of the RF receiving module. One output terminal of the RF transmitting module is connected to one output terminal of the local oscillator output module, through which the RF transmitting module transmits RF signals. The RF receiving module also has one input terminal connected to the other output terminal of the local oscillator output module, through which the RF receiving module receives RF signals and performs intermediate frequency (IF) signal data acquisition. The radio frequency transmission module includes a first integrated phase-locked loop frequency synthesizer, a balun, a first wideband 2-to-1 switch, a first bandpass filter, a 90-degree bridge, a second wideband 2-to-1 switch, a second bandpass filter, a first mixer, a channel filter bank, an amplifier, a step attenuator, a directional coupler, and a transmit output port. One differential output of the first integrated phase-locked loop frequency synthesizer is connected to the input of the balun, the output of the balun is connected to the input of the first wideband 2-to-1 switch, the output of the first wideband 2-to-1 switch is connected to the input of the first bandpass filter, and the output of the first bandpass filter is connected to... A 90-degree bridge is connected to the input of a second broadband 2-to-1 switch. The output of the second broadband 2-to-1 switch is connected to the input of a second bandpass filter. The output of the second bandpass filter is connected to the intermediate frequency input of a first mixer. The RF output of the first mixer is connected to the input of a channel filter bank. The output of the channel filter bank is connected to the input of an amplifier. The output of the amplifier is connected to the input of a step attenuator. The output of the step attenuator is connected to the input of a directional coupler. One output of the directional coupler is connected to the transmit output port for outputting a variable amplitude RF signal.

2. The vector network analyzer system with a single receiver architecture and no reference channel circuit as described in claim 1, characterized in that: The RF receiving module includes a receiving input port, a third broadband 2-to-1 switch, a fourth broadband 2-to-1 switch, a fixed attenuator, a second mixer, a third bandpass filter, a low-pass filter, and an ADC sampling unit. The input of the third broadband 2-to-1 switch is connected to the coupling output of the directional coupler. The input of the fourth broadband 2-to-1 switch is connected to both the output of the third broadband 2-to-1 switch and the receiving input port. The output of the fourth broadband 2-to-1 switch is connected to the input of the fixed attenuator. The output of the fixed attenuator is connected to the RF input of the second mixer. The intermediate frequency output of the second mixer is connected to the input of the third bandpass filter. The output of the third bandpass filter is connected to the RF input of the third mixer. The intermediate frequency output of the third mixer is connected to the input of the low-pass filter. The output of the low-pass filter is connected to the input of the ADC sampling unit. Another output of the first integrated phase-locked loop frequency synthesizer is connected to the local oscillator input of the third mixer.

3. The vector network analyzer system with a single receiver architecture and no reference channel circuit according to claim 2, characterized in that: The local oscillator output module is a second integrated phase-locked loop frequency synthesizer. The two output terminals of the second integrated phase-locked loop frequency synthesizer are respectively connected to the local oscillator input terminal of the first mixer and the local oscillator input terminal of the second mixer.

4. A vector network analyzer system with a single receiver architecture and no reference channel circuit as described in claim 3, characterized in that: The first integrated phase-locked loop frequency synthesizer generates a point frequency signal. By controlling the channel switching of the first broadband 2-to-1 switch and the second broadband 2-to-1 switch, RF radio frequency signals with phases of 0 degrees, 90 degrees, 180 degrees, and 270 degrees can be combined, i.e. , , , Four types of phase signals.

5. A vector network analyzer system with a single receiver architecture and no reference channel circuit as described in claim 4, characterized in that: When the vector network analyzer system performs S11 parameter measurement, it controls the third and fourth broadband two-to-one switches to import the coupled output signal of the directional coupler into the radio frequency receiving module. After digital sampling by the ADC sampling unit, the S11 parameter can be measured.

6. A vector network analyzer system with a single receiver architecture and no reference channel circuit as described in claim 5, characterized in that: When the vector network analyzer system performs S21 parameter measurement, the coupling output signal of the directional coupler is connected to a 50-ohm resistor by controlling the third broadband two-to-one switch, and the input RF signal of the receiving input port is introduced into the RF receiving module by controlling the fourth broadband two-to-one switch, thus realizing the measurement of S21 parameter.

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