CN115514426A

CN115514426A - High-sampling-rate single-acquisition-channel vector network analysis implementation method and system

Info

Publication number: CN115514426A
Application number: CN202211040020.2A
Authority: CN
Inventors: 刘世超; 宋淼; 李智; 李龙; 彭子健
Original assignee: CLP Kesiyi Technology Co Ltd
Current assignee: CLP Kesiyi Technology Co Ltd
Priority date: 2022-08-29
Filing date: 2022-08-29
Publication date: 2022-12-23

Abstract

The invention discloses a method and a system for realizing vector network analysis of a single acquisition channel with high sampling rate, wherein the method comprises the following steps: (1) When the signal is collected, the channel switch is switched to one of the three intermediate frequency signals of R, A and B; (2) Sampling by an ADC (analog to digital converter), mixing one path of collected intermediate frequency signal with an externally input digital local oscillator NCO, performing low-pass filtering on the mixed signal, performing data processing and storing; (3) After the set sampling time or the storage amount is reached, switching to another path of intermediate frequency signal by a channel switch, and executing the step (2); (4) Switching to the last path of intermediate frequency signal by a channel switch, and executing the step (2); (5) And finally, calculating corresponding amplitude and phase information according to the three paths of data. The implementation method and the system disclosed by the invention can effectively remove in-band noise, improve the signal-to-noise ratio of the whole test system and reduce the use amount of resources.

Description

High-sampling-rate single-acquisition-channel vector network analysis implementation method and system

Technical Field

The invention relates to the field of vector network analysis, in particular to a method and a system for realizing vector network analysis of a single acquisition channel with a high sampling rate.

Background

With the development of modern technology, the test indexes and functions are more and more diversified, higher requirements are put forward for high integration and miniaturization of test instruments, and the test instruments such as a vector signal transceiver and the like which have a simultaneous transceiving system not only perform the traditional signal transceiving function, but also can be combined with a radio frequency front end to realize the vector network analysis function. Many signal transceivers only have a single acquisition channel, and cannot use a conventional vector network analysis implementation method, so that research on the vector network analysis implementation method of the single acquisition channel is necessary.

At present, a traditional implementation method of single-acquisition channel vector network analysis based on a signal transceiving integrated hardware structure is that a single ADC samples three intermediate frequency signals of R, a, and B in a time-sharing manner, single data points of the three intermediate frequency signals of R, a, and B are sequentially acquired at fixed time intervals in the whole process, multiple rounds are circularly switched until the number of data points required by each path is acquired, and then data processing is performed, wherein a specific implementation manner is shown in fig. 1. The time-sharing sampler carries out counting control according to a data clock provided by the ADC, generates a switch control signal according to a fixed counting interval to switch the R, A and B paths of intermediate frequency signals, needs to ensure that the signals are stable after the channel switching is finished in the fixed counting interval, then obtains a sampling value of each channel point at each fixed moment, and the process is circulated for multiple times to respectively obtain the R, A and B paths of collected signals. Three routes of collected signals are respectively mixed with three digital local oscillator NCO, the three digital local oscillator NCO needs to ensure that initial phases are the same, and phases are superposed along with the enabling of each route of signals, so that the accuracy of measuring the phases can be ensured. After the frequency mixing is finished, the data enters a low-pass filter, high-frequency signals caused by the frequency mixing are removed, subsequent data processing is carried out according to the need, extraction filtering and other processing are carried out, finally, the data after the R, A and B three paths of intermediate frequency processing are obtained, and corresponding amplitude and phase information can be calculated according to the data of the three paths.

The method is not suitable for a vector signal transceiving system of a large-bandwidth channel, the three sampling periods in the technology are integral multiples of the sampling period of the ADC, the sampling period comprises channel switching, stable time and signal acquisition time, and the sampling period is far larger than the sampling period of the ADC. Aiming at a vector signal transceiving system of a large-bandwidth channel, an anti-aliasing analog filter at the front end of an ADC (analog to digital converter) has large bandwidth which is often hundreds of MHz or even higher, and channel noise of the broadband is introduced into the signal bandwidth by adopting the method, so that aliasing is caused, and a test index is influenced. In addition, the method needs frequent and repeated switching of the switch, and has high requirements on channel switching time and system stability. In addition, in the prior art, the data processing links are complex, three data processing links cannot be multiplexed in consideration of real-time requirements, 3 independent channels such as a digital local oscillator NCO and an extraction filter are needed, and the circuit structure is complex.

Disclosure of Invention

In order to solve the technical problems, the invention provides a method and a system for realizing the vector network analysis of a single acquisition channel with a high sampling rate, so as to achieve the purposes of effectively removing in-band noise, improving the signal-to-noise ratio of the whole test system and reducing the use amount of resources.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a method for realizing vector network analysis of a single acquisition channel with high sampling rate comprises the following processes:

(1) When the signal is collected, the channel switch is switched to one of the three intermediate frequency signals of R, A and B;

(2) Sampling by an ADC (analog to digital converter), mixing one path of collected intermediate frequency signal with an externally input digital local oscillator NCO, performing low-pass filtering on the mixed signal, performing data processing and storing;

(3) After the set sampling time or the storage amount is reached, switching to another path of intermediate frequency signal by a channel switch, and executing the step (2);

(4) After the set sampling time or the storage amount is reached, the second path of intermediate frequency signal is acquired, the channel switch is switched to the last path of intermediate frequency signal, and the step (2) is executed, so that the acquisition of three paths of intermediate frequency signals is completed;

(5) And finally, calculating corresponding amplitude and phase information according to the three paths of data.

In the scheme, the three paths of intermediate frequency signals R, A and B keep fixed phase difference with an ADC acquisition clock and also keep fixed phase difference with an ADC digital output clock.

In the scheme, the three paths of intermediate frequency signals R, A and B and the digital local oscillator NCO constructed by the ADC digital output clock also keep fixed phase difference.

In the above scheme, the data processing in step (2) includes decimation and filtering.

In the scheme, in the whole process from the step (1) to the step (5), the digital local oscillator NCO keeps running all the time.

In the scheme, the controller generates the switch control signal according to the data storage condition and the sampling time to control the switching of the channel switch.

A high-sampling-rate single-acquisition-channel vector network analysis implementation system comprises a channel switch, an ADC (analog to digital converter), a frequency mixer, a low-pass filter, a data processor and a data memory which are sequentially connected, wherein the frequency mixer is further connected with a digital local oscillator NCO, the channel switch is connected with a radio frequency front end, and a controller is connected with the data memory and the channel switch.

Through the technical scheme, the method and the system for realizing the vector network analysis of the single acquisition channel with the high sampling rate have the following beneficial effects:

1. according to the invention, the three paths of intermediate frequency signals R, A and B are not required to be frequently acquired at fixed time in a time-sharing manner, the three paths of signals are respectively acquired by using the ADC in sequence, and the in-band noise can be effectively removed through subsequent data processing, so that the signal-to-noise ratio of the whole test system is improved.

2. According to the invention, three paths of signals are sequentially acquired and completed by using the ADCs respectively, and the three paths of data are multiplexed and mixed based on a pipeline structure and a subsequent data processor, so that the use amount of resources can be reduced.

3. The invention can be suitable for a hardware system integrating large-bandwidth signal receiving and transmitting, the data rate of three paths of intermediate frequency acquisition is consistent with the ADC sampling rate, and in-band noise can be effectively removed.

4. The invention completes the processing process once, the channel switch only needs to be switched for 3 times, and frequent switching is not needed, thereby improving the stability of the system.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.

FIG. 1 is a flow chart of a method for implementing vector network analysis in the prior art;

fig. 2 is a flowchart of a method for implementing vector network analysis of a single acquisition channel with a high sampling rate according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.

The invention provides a method for realizing vector network analysis of a single acquisition channel with a high sampling rate, which comprises the following steps as shown in figure 2:

(2) Sampling by an ADC (analog to digital converter), mixing one path of collected intermediate frequency signal with an externally input digital local oscillator NCO, performing low-pass filtering on the mixed signal, performing data processing such as extraction and filtering, and storing;

(4) After the set sampling time or the storage amount is reached, the second path of intermediate frequency signals are acquired, the channel switch is switched to the last path of intermediate frequency signals, the step (2) is executed, and the acquisition of three paths of intermediate frequency signals is completed;

In the invention, the three paths of intermediate frequency signals R, A and B keep fixed phase difference with an ADC acquisition clock and also keep fixed phase difference with an ADC digital output clock. And the R, A and B three paths of intermediate frequency signals and a digital local oscillator NCO constructed by using an ADC digital output clock also keep a fixed phase difference.

In the whole process from the step (1) to the step (5), the digital local oscillator NCO keeps running all the time and cannot be interrupted, so that the correctness of the phase test is ensured.

In the invention, the controller generates a switch control signal according to the data storage condition and the sampling time to control the switching of the channel switch. In the invention, a treatment process can be completed only by switching three times without frequently switching a switch.

A high sampling rate single acquisition channel vector network analysis implementation system comprises a channel switch, an ADC, a frequency mixer, a low-pass filter, a data processor and a data memory which are sequentially connected, wherein the frequency mixer is further connected with a digital local oscillator NCO, the channel switch is connected with a radio frequency front end, and a controller is connected with the data memory and the channel switch.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for realizing vector network analysis of a single acquisition channel with high sampling rate is characterized by comprising the following processes:

2. The method as claimed in claim 1, wherein the three intermediate frequency signals R, a, and B are all kept at a fixed phase difference from the ADC acquisition clock, and also kept at a fixed phase difference from the ADC digital output clock.

3. The method as claimed in claim 2, wherein the R, a, B three intermediate frequency signals and the digital local oscillator NCO constructed by the ADC digital output clock also maintain a fixed phase difference.

4. The method of claim 1, wherein the data processing in step (2) comprises decimation and filtering.

5. The method for realizing the vector network analysis of the single acquisition channel with the high sampling rate according to claim 1, wherein in the whole process from the step (1) to the step (5), the digital local oscillator NCO keeps running all the time.

6. The method of claim 1, wherein the controller generates the switch control signal to control the switching of the channel switch according to the data storage condition and the sampling time.

7. The system is characterized by comprising a channel switch, an ADC (analog to digital converter), a mixer, a low-pass filter, a data processor and a data memory which are sequentially connected, wherein the mixer is also connected with a digital local oscillator NCO, the channel switch is connected with a radio frequency front end, and a controller is connected with the data memory and the channel switch.