CN104362986B - High-power intermodulation distortion detection means and detection method - Google Patents

Abstract

The invention provides a high-power intermodulation distortion detection device and detection method. The device includes detection equipment and a detection circuit. The device to be tested is connected to the detection device through the detection circuit. The detection device has an RF source card and an arbitrary waveform generator AWG. The detection circuit includes a power amplifier, a first and a second filter and an attenuator. . The method is as follows: the arbitrary waveform generator sends an I/Q modulation signal, the RF source card sends a carrier signal, and then loads the I/Q modulation signal into the carrier signal to obtain a dual-tone signal for detecting intermodulation distortion. Only one RF source card is needed to send out the carrier signal to achieve the purpose of forming a dual-tone signal by one RF source card, reducing the use of RF source cards and reducing production costs. Further, the bandwidth and power of the dual-tone signal can be determined by the I/Q modulation signal sent by the arbitrary waveform generator, which can generate dual-tone signals with the same power bandwidth range, and can also generate dual-tone signals with smaller bandwidths but different powers. Dual-tone signal, with better operation selectivity.

Description

High-power intermodulation distortion detection device and detection method

technical field

The invention relates to the field of wireless communication, in particular to a high-power intermodulation distortion detection device and detection method.

Background technique

In a wireless communication system, especially a radio frequency front-end circuit, there are often nonlinear non-idealities. Intermodulation Distortion (IMD for short) refers to the sum and difference distortion of an input signal introduced by an amplifier. When the input end of the wireless communication system receives external interference, especially there are two or more interference signals of different frequencies at the same time. After the interference signal is affected by the nonlinearity of the system itself, an intermodulation component is generated. If the frequency of the intermodulation component is similar to the target signal, it will interfere with the target signal, causing difficulty in demodulation and reducing the sensitivity of the system. (Sensitivity). Specifically, third-order intermodulation distortion generated by two frequencies is a common problem in narrowband communication systems. When there are two (or more) signals in the system, strong intermodulation products are usually produced. If the frequency of the input signal is f ₁ and f ₂ , its second-order harmonics (2f ₁ and 2f ₂ ) will further generate intermodulation distortion, and its largest intermodulation product is the third-order intermodulation (2f ₁ -f ₂ and 2f ₂ -f ₁ ) Regardless of whether it is an active device or a passive device, such as an amplifier, a mixer, and a filter, etc., third-order intermodulation products will be generated. These intermodulation products degrade the performance of many communication systems. Excessive third-order intermodulation (IMD3) products in the transmitted signal can interfere with other receivers and eventually cause the receiver to malfunction.

Please refer to FIG. 1. FIG. 1 is a schematic structural diagram of an intermodulation distortion detection device in the prior art. The detection structure includes: a detection device 10 and a detection circuit, wherein the detection device 10 is usually a 93K test device for performing 2nd-order or 3rd-order For the detection of order intermodulation distortion signals, several RF source cards (RF Source Cards) can be inserted inside. There are usually multiple function cards inside the 93K test equipment, such as digital cards (Digital Cards), DPS cards (for simple illustration , the digital card and DPS card are not shown in Figure 1) and the arbitrary waveform generator (AWG). The detection circuit sequentially includes a power amplifier (PA) 20, a combiner (Combiner) 30, a DC signal filter (DC Block) 40, an attenuator (Attenuator) 60, a power splitter (Splitter) 70 and a filter (BFP) 80 . In the prior art, when performing intermodulation distortion detection, it is necessary to send out a two-tone signal, and then feed back the generated intermodulation distortion signal to the detection device 10 after passing through the device under test (DUT) 50 connected in the detection circuit, that is, 93K test The detection and analysis of intermodulation distortion signals are carried out in the equipment.

Specifically, one RF source card can only send out one single-tone signal. In order to obtain a dual-tone signal, two RF source cards are required to send single-tone signals of different frequencies to form a dual-tone signal. For example, RF source cards S1 and S2 are used to send out single-tone signals respectively, wherein S1 sends out low-power single-tone signals, such as 0dBM, so the single-tone signals sent by S1 need to be amplified by the power amplifier 20, for example, amplified to 20dBM, At this time, S2 sends another single-tone signal, for example, the power is -15dBM, and the two single-tone signals are processed by the combiner 30 to form the dual-tone signal required for detection. In order to remove the generated DC signal, it is guaranteed to enter the device under test. When the two-tone signal is pure at 50, usually the two-tone signal is first filtered through the DC signal filter 40 to filter the DC signal, and then through the device under test 50, because the device under test 50 is a nonlinear device, it will intermodulate the distorted signal , similarly, in order to remove the DC signal, the dual-tone signal will also pass through the DC signal filter 40 to filter the DC signal after passing through the device under test 50, and then the dual-tone signal needs to undergo corresponding power attenuation through the attenuator 60, and then use The power divider 70 divides the two-tone signal and the intermodulation distortion signal into two branches, and the two-tone signal of one branch is directly fed back to the third RF source card S3 in the detection device 10, and is compared with the initial two-tone signal. For signal comparison, the two-tone signal of the other branch is fed back to the fourth RF source card S4 in the detection device 10 through the filter 80 for analysis of intermodulation distortion. The filter 80 can only pass the intermodulation distortion signal, so as to facilitate the analysis of the intermodulation distortion signal.

In the prior art, it is necessary to use two RF source cards to provide single-tone signals of different frequencies, so that a dual-tone signal can be formed. If the dual-tone signal after passing the device under test is compared with the initial dual-tone signal, then A third RF source card is required, and then a fourth RF source card is required for analysis of intermodulation distortion signals. However, RF source cards are very expensive, and the use of multiple RF source cards will increase the corresponding cost, which is not conducive to mass production. Therefore, those skilled in the art need to solve the problem of high cost caused by using more RF source cards for testing.

Contents of the invention

The purpose of the present invention is to provide a high-power intermodulation distortion detection device and detection method for the defects of the prior art, which can reduce the use of RF source cards and reduce detection costs.

In order to achieve the above object, the present invention proposes a high-power intermodulation distortion detection device, including: a detection device and a detection circuit, wherein, the detection device is provided with an RF source card and an arbitrary waveform generator, and the device to be tested passes through the The detection loop is connected with the detection equipment, the RF source card sends out a carrier signal, the arbitrary waveform generator sends out an I/O modulation signal, and the I/O modulation signal and the carrier signal are loaded together to form a detection interaction Tune a distorted two-tone signal. The detection loop includes a power amplifier, a first filter, a second filter and an attenuator, one end of the power amplifier is connected to the detection device, the other end is connected to one end of the first filter, and the other end of the first filter is The device under test is connected, one end of the attenuator is connected to the device under test, the other end is connected to one end of a second filter, and the other end of the second filter is connected to the detection device.

Further, in the high-power intermodulation distortion detection device, the detection loop further includes a first DC signal filter and a second DC signal filter, and the first DC signal filter is connected to the Between the first filter and the device under test, the second DC signal filter is connected between the attenuator and the device under test.

Further, in the high-power intermodulation distortion detection device, the detection device is provided with an RF signal sending source card and an RF signal receiving source card, and the RF signal sending source card sends a carrier signal, and the RF signal The receiving source card receives and analyzes intermodulation distortion signals.

Further, in the high-power intermodulation distortion detection device, an RF signal comparison source card is also provided in the detection device, which is used for comparing the initial two-tone signal.

Further, in the high-power intermodulation distortion detection device, the detection circuit further includes a power divider, the power divider is connected between the attenuator and the detection device, and the two-tone signal and The intermodulation distortion signal is divided into two branches, one branch is directly connected to the RF signal comparison source card in the detection device, and the other branch is connected to the detection device through the second filter.

Further, the present invention also proposes a high-power intermodulation distortion detection method, using the high-power intermodulation distortion detection device as described above, the method includes steps:

The RF source card sends out the carrier signal, and the arbitrary waveform generator sends out the I/Q modulation signal;

Load the I/Q modulation signal to the carrier signal to obtain a dual-tone signal;

The two-tone signal is fed back to the detection equipment after passing through the detection circuit and the device under test to detect the intermodulation distortion.

Further, in the method for detecting high-power intermodulation distortion, the I/Q modulation signal sent by the arbitrary waveform generator is a single-tone signal, which is loaded onto the carrier signal and mirrored into another single-tone signal to obtain a two-tone signal with a consistent power bandwidth twice the maximum bandwidth of the arbitrary waveform generator.

Further, in the method for detecting high-power intermodulation distortion, the I/Q modulation signal sent by the arbitrary waveform generator is a two-tone signal, which is loaded onto the carrier signal, and the image signal is suppressed to obtain The power adjustable bandwidth is a two-tone signal with twice the maximum bandwidth of the arbitrary waveform generator.

Compared with the prior art, the present invention has the following obvious outstanding qualitative features and significant advantages: in the present invention, the arbitrary waveform generator AWG sends the I/Q modulation signal, the RF source card sends the carrier signal, and then the I/Q The modulated signal is loaded into the carrier signal to obtain a two-tone signal for detecting intermodulation distortion. Only one RF source card is needed to send the carrier signal to achieve the purpose of forming a dual-tone signal by one RF source card, reducing the use of RF source cards and reducing production costs.

Further, the bandwidth and power of the dual-tone signal can be determined by the I/Q modulation signal sent by the arbitrary waveform generator, which can generate a dual-tone signal with the same power bandwidth and a wide range, and can also generate a dual-tone signal with a smaller bandwidth but different power. Dual-tone signal, with better operation selectivity.

Description of drawings

FIG. 1 is a schematic structural diagram of an intermodulation distortion detection device in the prior art;

2 is a schematic structural diagram of an intermodulation distortion detection device in Embodiment 1 of the present invention;

Fig. 3 is a frequency-power schematic diagram of forming a dual-tone signal in Embodiment 1 of the present invention;

4 is a schematic structural diagram of an intermodulation distortion detection device in Embodiment 2 of the present invention;

FIG. 5 is a schematic diagram of frequency-power for forming a dual-tone signal in Embodiment 2 of the present invention.

Detailed ways

The high-power intermodulation distortion detection device and detection method of the present invention will be described in more detail below in conjunction with the accompanying drawings and preferred embodiments. Among the preferred embodiments, it should be understood that those skilled in the art can modify the present invention described here, while still The advantageous effects of the present invention are realized. Therefore, the following description should be understood as the broad knowledge of those skilled in the art, but not as a limitation of the present invention.

Embodiment one:

Please refer to FIG. 2 . In this embodiment, a high-power intermodulation distortion detection device is proposed, including: a detection device 100 and a detection circuit. The device under test 500 is connected to the detection device 100 through the detection circuit. Among them, RF source card and arbitrary waveform generator AWG are arranged in testing equipment 100, and testing equipment 100 can be 93K testing equipment, and multiple RF source cards can be inserted inside it, and be provided with multiple function cards, arbitrary waveform generator AWG It is a kind of function card. Among them, in this embodiment, the detection device 100 is inserted with two RF source cards, which are the RF signal transmission source card S1 and the RF signal reception source card S2, wherein the RF signal transmission source card S1 is used to send the carrier signal, and the RF signal The receiving source card S2 is used to receive the intermodulation distortion signal for analysis. The arbitrary waveform generator AWG is used to send out the I/O modulation signal, and load the I/O modulation signal and the carrier signal together to form a dual-tone signal for detecting intermodulation distortion. Only one RF source card is needed to send the carrier signal to achieve the purpose of forming a dual-tone signal by one RF source card, reducing the use of RF source cards and reducing production costs.

In this embodiment, the detection circuit includes a power amplifier 200, a first filter 310, a second filter 320, and an attenuator 600. One end of the power amplifier 200 is connected to the detection device 100, and the other end is connected to one end of the first filter 310. The other end of the first filter 310 is connected to the device under test 500 , one end of the attenuator 600 is connected to the device under test 500 , the other end is connected to one end of the second filter 320 , and the other end of the second filter 320 is connected to the testing device 100 . After the two-tone signal is amplified by the power amplifier 200, the distorted signal generated by the amplifier 200 is filtered through the first filter 310, so that the pure two-tone signal enters the device under test 500, and then the two-tone signal passes through the attenuator 600 for further processing. After being attenuated and filtered by the second filter 320 , the RF signal receiving source card S2 entering the detection device 100 detects the intermodulation distortion signal.

Wherein, the first filter 310 adopts a bandpass filtering manner, and the second filter 320 may adopt a narrowband bandpass filtering manner or a narrowband bandstop filtering manner for filtering. Wherein, the first filter 310 is used to filter the distorted signal to ensure the purity of the two-tone signal before entering the device under test 510, and the second filter 320 is used to filter out the two-tone signal and only pass the intermodulation distortion signal that needs to be detected, such as The third-order intermodulation distortion signal, because the power difference between the intermodulation distortion signal and the two-tone signal is large, and the detection dynamic range of the detection device 100 is limited, in order to make the detection accurate, it is necessary to remove the two-tone signal, and only keep the intermodulation that needs to be detected distorted signal.

The detection circuit also includes a first DC signal filter 410 and a second DC signal filter 420, the first DC signal filter 410 is connected between the first filter 310 and the device under test 500, and the second DC signal filter 420 is connected between the attenuator 600 and the device under test 500, both of which are used to filter the DC signal to avoid the interference of the DC signal.

On the other side of this embodiment, a high-power intermodulation distortion detection method is also proposed, using the high-power intermodulation distortion detection device as described above, the method includes steps:

S1: The RF source card sends out the carrier signal, and the arbitrary waveform generator AWG sends out the I/Q modulation signal;

Please refer to FIG. 3 , in step S1, the RF signal source card S1 is used to send the carrier signal f1, and the I/Q modulation signal sent by the arbitrary waveform generator AWG is a single tone signal f2.

S2: Load the I/Q modulation signal onto the carrier signal to obtain a dual-tone signal;

Please continue to refer to Figure 3, load the I/Q modulation signal from the arbitrary waveform generator AWG as a single tone signal f2 onto the carrier signal f1, mirror it into another single tone signal, and its frequency is f1+f2 on the frequency spectrum, thus Get a two-tone signal. It should be pointed out that, since the power of the other single-tone signal f1+f2 mirrored is the same as that of the single-tone signal f2 sent by the I/Q modulation signal, the bandwidth of the obtained dual-tone signal can reach two times the maximum bandwidth of the arbitrary waveform generator AWG. times. Since the other tone signal f1+f2 is formed by the I/Q modulation signal sent by the arbitrary waveform generator AWG as a mirror image of the tone signal f2, the power of the two is the same and cannot be changed according to the requirements of the test conditions, but can only be suppressed.

S3: The two-tone signal is fed back to the detection device 100 after passing through the detection circuit and the device under test 500 to detect intermodulation distortion.

In step S3, the two-tone signal passes through the device under test 500 to generate an intermodulation distortion signal, and the generated intermodulation distortion signal is then fed back to the RF signal receiving source card S2 in the detection device 100 for distortion analysis.

Embodiment two:

Please refer to Fig. 4, in the present embodiment, the proposed high-power intermodulation distortion detection device also includes a detection device 100 and a detection circuit, the difference is that a RF signal comparison source card S3 is also provided in the detection device 100 for comparison Initial two-tone signal. In addition, the detection circuit also includes a power divider 700 on the basis of Embodiment 1. The power divider 700 is connected between the attenuator 600 and the detection device 100, and it is used to divide the two-tone signal and the intermodulation distortion signal into two branches. One branch is directly connected with the RF signal comparison source card S3 in the detection device for signal comparison and analysis, and the other branch is connected with the RF signal receiving source card S2 in the detection device through the second filter 320 for use in for analyzing intermodulation distortion signals. The rest of the components are the same as those in Embodiment 1. For details, please refer to Embodiment 1, which will not be repeated here.

In addition, in the high-power intermodulation distortion detection method proposed in this embodiment, the general steps are the same as in the first embodiment, the difference is that the I/Q modulation signal sent by the arbitrary waveform generator AWG is a two-tone The signal includes two frequencies, as shown by f2 and f3 in Figure 5, and the I/Q modulation signal is loaded onto the carrier signal f1 to obtain the two-tone signal required for detection. At this time, the interference signals f1+f2 and f1+f3 generated during loading can be suppressed by adjusting the power and frequency of the I/Q modulation signal, and the interference signals f1+f2 and f1+f3 can be completely suppressed. At this time, the obtained dual-tone signals can have different powers, but their bandwidth is limited by the maximum bandwidth of the arbitrary waveform generator AWG, that is, the maximum bandwidth can only be the maximum bandwidth of the arbitrary waveform generator AWG.

Therefore, it can be known from Embodiment 1 and Embodiment 2 that the number of RF source cards in the detection device 100 and whether the dual-tone signal to be obtained requires a larger bandwidth or different power can be determined by specific detection requirements.

To sum up, in the high-power intermodulation distortion detection device and detection method provided by the embodiments of the present invention, the arbitrary waveform generator sends out the I/Q modulation signal, the RF source card sends out the carrier signal, and then loads the I/Q modulation signal into the carrier The signal can then be obtained as a two-tone signal to detect intermodulation distortion. Only one RF source card is needed to send the carrier signal to achieve the purpose of forming a dual-tone signal by one RF source card, reducing the use of RF source cards and reducing production costs. Further, the bandwidth and power of the dual-tone signal can be determined by the I/Q modulation signal sent by the arbitrary waveform generator, which can generate a dual-tone signal with the same power bandwidth and a wide range, and can also generate a dual-tone signal with a smaller bandwidth but different power. Dual-tone signal, with better operation selectivity.

The foregoing are only preferred embodiments of the present invention, and do not limit the present invention in any way. Any person skilled in the technical field, within the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which does not depart from the technical solution of the present invention. The content still belongs to the protection scope of the present invention.

Claims (5)

1. a kind of high-power intermodulation distortion detection means, including detection device 100 and measure loop, device under test 500 pass through institute State measure loop with the detection device 100 to be connected, RF sources card and Arbitrary Waveform Generator are provided with the detection device 100 AWG, RF sources card send carrier signal, and the Arbitrary Waveform Generator AWG sends I/O modulated signals, the I/O is modulated Signal forms the two-tone signal as detection intermodulation distortion together with carrier signal loading, it is characterised in that described to detect back Road includes power amplifier 200, the first wave filter 310, the second wave filter 320 and attenuator 600, the power amplifier 200 One end is connected with the detection device 100, and the other end connects one end of the first wave filter 310, the other end of the first wave filter 310 Device under test 500 is connected, described one end of attenuator 600 is connected with the device under test 500, and the other end connects the second wave filter 320 one end, the other end of the second wave filter 320 are connected with the detection device 100；

RF sources card in the detection device 100 includes RF signal transmission source card S1 and RF signal receiving source cards S2, the RF letters Number transmission source card S1 sends carrier signal, and the RF signal receiving source cards S2 is received and analyzed intermodulation distortion signals；

RF sources card in the detection device is additionally provided with RF signal reference source card S3, for comparing initial two-tone signal；

The measure loop also includes a power splitter 700, and the power splitter 700 is connected to the attenuator 600 and detection is set Between standby 100, the two-tone signal and intermodulation distortion signals are divided into two branch roads, a branch road directly with the detection device 100 In RF signal reference source cards S3 be connected, another branch road passes through the RF in second wave filter 320 and the detection device 100 Signal receiving source card S2 is connected.

2. high-power intermodulation distortion detection means as claimed in claim 1, it is characterised in that：The measure loop also includes one Individual first direct current signal filter 410 and a second direct current signal filter 420, the first direct current signal filter 410 It is connected between first wave filter 310 and device under test 500, the second direct current signal filter 420 is connected to described Between attenuator 600 and device under test 500.

A kind of 3. high-power intermodulation distortion detection method, using high-power intermodulation distortion detection dress as claimed in claim 1 or 2 Put and operated, it is characterised in that concrete operation step is as follows：

A.RF sources card sends carrier signal, and Arbitrary Waveform Generator AWG sends I/Q modulated signals；

B. I/Q modulated signals are loaded onto in carrier signal, obtain two-tone signal；

C. the two-tone signal feeds back to detection device 100 after measure loop and device under test 500 and carries out intermodulation distortion Detection.

4. high-power intermodulation distortion detection method as claimed in claim 3, it is characterised in that：The Arbitrary Waveform Generator The I/Q modulated signals that AWG is sent are tone signal, are loaded into the carrier signal, and mirror image obtains into another tone signal The consistent two-tone signal with twice of a width of Arbitrary Waveform Generator maximum bandwidth of power.

5. high-power intermodulation distortion detection method as claimed in claim 3, it is characterised in that the Arbitrary Waveform Generator The I/Q modulated signals that AWG is sent are two-tone signal, are loaded into the carrier signal, and suppress image signal, obtain work( Rate BREATHABLE BANDWIDTH is the two-tone signal of one times of Arbitrary Waveform Generator maximum bandwidth.