CN116707528A

CN116707528A - Automatic detection method for radio frequency signal amplitude based on programmable function

Info

Publication number: CN116707528A
Application number: CN202310901723.8A
Authority: CN
Inventors: 郭文龙; 郑志伟; 向霖; 覃勇; 尹怡辉; 朱宏韬; 黄天发; 李锐清; 张维路
Original assignee: CETC 34 Research Institute
Current assignee: CETC 34 Research Institute
Priority date: 2021-03-10
Filing date: 2021-03-10
Publication date: 2023-09-05
Also published as: CN113014260A

Abstract

The application provides an automatic detection method of radio frequency signal amplitude based on programmable function, which obtains a corresponding relation table of signal amplitude and AD sampling value through signal measurement; then embedding a read-write command for communicating with a computer in an MCU program in the radio frequency module, and writing data into a nonvolatile memory in the MCU when the computer inputs the write command; when a read command is input, data in a nonvolatile memory in the MCU is reported to a computer, an AD sampling value is converted into 16 system, and a corresponding relation table of signal amplitude and the AD sampling value is written into the nonvolatile memory in the MCU through the input command of the computer, so that data solidification is completed; and finally, the MCU periodically reads the AD sampling value of any signal input into the radio frequency module, reads a corresponding relation table of the signal amplitude and the AD sampling value in the internal nonvolatile memory, and finds out the signal amplitude corresponding to the AD sampling value of the input signal in the relation table by using a halving search method.

Description

Automatic detection method for radio frequency signal amplitude based on programmable function

The application discloses a division application of a patent application named as an automatic detection method of radio frequency signal amplitude based on a programmable function, wherein the application date of the original application is 2021, 03 and 10, and the application number is 202110260326.8.

Technical Field

The application relates to the technical field of detection of radio frequency signals, in particular to an automatic detection method of radio frequency signal amplitude based on a programmable function.

Background

Radio-frequency signal optical fiber (RoF) is used as a technology for the vigorous development, radio-frequency signals are modulated on optical signals, the characteristics of the optical fiber, such as wide frequency band, small loss and light weight, are fully utilized, and high-capacity data high-speed remote transmission is realized by an optical fiber link.

In the aspect of signal transmission, the defect that a ground station control center and an antenna are installed at the same place in construction can be overcome by utilizing the radio frequency signal optical fiber transmission technology. The antenna field is arranged at a remote place (good signal quality); the data processing equipment, the demodulator and the frequency converter can be arranged in a data center (convenient for life) in a city which is tens of kilometers away from the antenna field, and workers can directly go to the data center to work, so that the trouble and waste caused by reciprocating between the antenna array and the office are avoided.

The electromagnetic interference and multiple data connection problems can be well solved by utilizing the radio frequency signal optical fiber transmission technology. A very thin and lightweight optical cable comprising 10 core 20 core or more single mode optical fibers facilitates the connection of equipment to the antenna site and eliminates expensive sealed waveguides, coaxial cables or copper cables. And simultaneously solves the RFI/EMI problem among multiple cables.

In mobile communications, the most important flexible application of the rf optical fiber transmission system is broadband indoor coverage, such as subways, large malls, train stations, airports, exhibition centers, and the like.

With the continuous development of military technology, the radio frequency signal optical fiber transmission technology is widely applied to occasions such as satellite communication, radar detection, electronic countermeasure and the like.

At present, in the production and debugging process of the radio frequency module, the detection program of the amplitude of the radio frequency signal needs to be customized one by one, which is unfavorable for mass production.

The radio frequency signal is an electric signal with certain frequency and power (i.e. amplitude), the radio frequency module is used for processing or transmitting the radio frequency signal, the module is provided with software besides hardware, a carrier operated by the software is an MCU chip in the radio frequency module, and one of the functions of the software is to calculate the amplitude of the radio frequency signal.

As shown in the following figure 1, the radio frequency signal is firstly sent to an amplifier in the radio frequency module, and the detection signal output by the amplifier is subjected to AD sampling, namely, the analog quantity is converted into the digital quantity, so that the processing of a computer is facilitated. The sampling result is an integer, under the condition of 10-bit precision, the range is 0-1023, the amplitude of the signal is reflected by the sampling result, the MCU program uses the sampling result to carry out a series of calculations, the calculated signal amplitude can be obtained by inquiring a computer, namely, a command is input on the computer, the command is sent to the MCU through serial port communication, and the MCU returns the result.

In order to calculate the signal amplitude, in the prior art, signal measurement is first performed, because the relationship between the AD sampling value and the signal amplitude has no fixed rule, but in general, the larger the signal amplitude is, the larger the AD sampling value is, and the change rate (i.e., slope: Δamplitude/Δad sampling value) is closely related to the hardware circuit.

And designing a set of measurement commands communicated with a computer in the MCU program, namely sending the commands to the MCU through the computer, and reporting the AD sampling value of the current radio frequency signal by the MCU. The radio frequency signal source (signal source for short) gives signals with different amplitude values (the signals are sent from the signal source, the amplitude values can be directly read from the signal source display screen), the detection output by the amplifier is different, and the AD sampling value obtained by the MCU is different after AD conversion. Given the signal amplitude of the whole range which can be processed by the radio frequency module one by one, a corresponding relation table of the signal amplitude and the AD sampling value is obtained, as shown in the following table 1, the maximum signal amplitude output by the signal source is 0dBm, the minimum signal amplitude is-50 dBm, the signals are sequentially decreased by 2dB, the AD sampling values of 26 signals are measured, the adjacent AD sampling values are calculated in the table simultaneously, so as to observe whether the change is linear, and the change of the AD sampling values and the change of the amplitude are in a consistent linear relation when the signal amplitude is-30 dBm to 0dBm, and the AD sampling value is approximately reduced by 12.2 when the amplitude is reduced by 1 dB. When the amplitude is less than-30 dBm, no obvious linear change exists, and only an approximate linear interval can be divided artificially.

TABLE 1L frequency band analog receiving plugboard signal measurement

By dividing the linear interval and approximating the slope value of each interval, the signal amplitude can be calculated in the MCU program, firstly, the AD sampling value is 643 when the signal is-30 dBm is taken as a reference point, when the AD sampling value of an unknown signal is 655 (approximately643+12.2), the signal amplitude is about-29 dBm, and the like, and any AD sampling value in a given dynamic range can be approximated to calculate the signal amplitude.

It is obvious that the above method has at least 3 defects, firstly, when the signal is smaller than-30 dBm, the error between the calculation result and the actual result will become larger because the linear relation is not obvious; secondly, MCU programs cannot be used universally, which is unfavorable for mass production and software archiving. For example, if there is another radio frequency module, because of the difference of components, the corresponding relation table between the measured signal amplitude and the AD sampling value changes, it is necessary to re-evaluate the linear interval and calculate the slope, and then modify the program, and in the worst case, the program of each module is different; thirdly, the modification of the result is inconvenient, for example, when the detection result needs to be modified after the module is debugged, the program needs to be modified again, which obviously takes time and labor.

Disclosure of Invention

In order to overcome the defects of the prior art, the application aims to provide an automatic detection method for the amplitude of a radio frequency signal based on a programmable function.

In order to achieve the above object, the present application provides the following solutions:

1. an automatic detection method of radio frequency signal amplitude based on programmable function is characterized by comprising the following steps:

1) Signal measurement: embedding a measurement command into an MCU program in a radio frequency module to be measured, inputting radio frequency signals with different amplitudes in a full range which can be processed by the module to the radio frequency module through a radio frequency signal source, and after the radio frequency signals are subjected to amplifier and AD conversion in sequence, transmitting an AD sampling value of the radio frequency signals to a PC end through a serial port by the MCU to obtain a corresponding relation table of the signal amplitude and the AD sampling value;

2) And (3) data curing: embedding a read-write command for communicating with a computer in an MCU program in the radio frequency module, and writing data into a nonvolatile memory in the MCU when the computer inputs the write command; when a read command is input, reporting data in a nonvolatile memory in the MCU to a computer, converting the AD sampling value obtained in the step 1) into 16 system, and writing a corresponding relation table of signal amplitude and the AD sampling value into the nonvolatile memory in the MCU through the input command of the computer to finish data solidification;

3) Automatic calculation: after the MCU program is started, periodically reading the AD sampling value of any signal input into the radio frequency module, reading a corresponding relation table of the signal amplitude value and the AD sampling value stored in the internal nonvolatile memory, and finding out the signal amplitude value corresponding to the AD sampling value of the input signal in the relation table by using a halving search method;

in step 3), the method of using the halving search method to find out the signal amplitude corresponding to the AD sampling value of the input signal in the relation table comprises the following specific steps:

3-1) setting two variables left and right for recording the index range of the search; wherein left initially records the index of the first AD sampling value, right initially records the index of the last AD sampling value, and each search is compared with the search value by using an intermediate index, namely, the AD sampling value of mid= (left+right)/(2);

3-2) if the lookup value is greater than or equal to the intermediate value, indicating that the lookup value is positioned on the left of the intermediate value, setting right as mid-1, and that the next sequence to be searched is positioned in the interval of the index [ left, mid-1 ];

3-3) if the search value is less than the intermediate value, indicating that the search value is positioned on the right of the intermediate value, setting left as mid+1, and the sequence to be searched next time is positioned in the interval of the index [ mid+1, right ];

3-4) repeating steps 3-2) and 3-3) until left > right ends; after the end, the values of left and right indicate the range of the search value, and the signal amplitude is calculated according to the range;

3-5) if left is 0, indicating that the search value is greater than or equal to the AD sampling value corresponding to index 0, indicating that the signal amplitude is greater than or equal to 0dBm, and the signal is in a saturated state;

3-6) if left is the last index value plus 1, indicating that the search value is smaller than the AD sampling value corresponding to the last index value, indicating that the signal amplitude is smaller than the amplitude represented by the last AD sampling value, and indicating that the signal is in a no-signal state; otherwise, the search value is between the AD sampling value with index right and the AD sampling value with index left, that is, the signal amplitude is between the amplitude with index right and the amplitude with index left, at this time, left is greater than right by 1, at this time, the change of the signal amplitude in the interval is small, and the amplitude in the interval and the AD sampling value are considered to be in a linear relationship, so as to perform linear calculation.

The automatic detection method of the radio frequency signal amplitude based on the programmable function provided by the application has the following advantages:

1) The read-write function of the nonvolatile programmable memory inside the MCU is utilized to store the measurement data, an external memory chip is not needed, the access efficiency is improved, and the cost of the device is saved;

2) The separation of the program and the data is realized, the unification of the program is realized, and the archiving is convenient;

3) The measurement data can be repeatedly written in and modified for many times, so that the correction is convenient;

4) The code execution is more efficient by adopting the halving search method, and the accuracy of the calculated result is high;

5) The measurement data can be sent to debugging personnel for measurement and solidification, and research and development personnel can concentrate on software and hardware design, so that the board card is convenient for mass production.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions of the prior art, the drawings that are needed in the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of RF signal amplitude measurement;

FIG. 2 is a schematic diagram of data curing;

FIG. 3 is a schematic diagram of a data curing command;

FIG. 4 is a schematic diagram of a read nonvolatile memory command.

Detailed Description

The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

The terms "first," "second," "third," and "fourth" and the like in the description and in the claims and drawings are used for distinguishing between different objects and not necessarily for describing a particular sequential or chronological order. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, inclusion of a list of steps, processes, methods, etc. is not limited to the listed steps but may alternatively include steps not listed or may alternatively include other steps inherent to such processes, methods, products, or apparatus.

In order that the above-recited objects, features and advantages of the present application will become more readily apparent, a more particular description of the application will be rendered by reference to the appended drawings and appended detailed description.

Examples:

an automatic detection method of radio frequency signal amplitude based on programmable function includes the following steps:

1) Signal measurement: as shown in fig. 1, a measurement command is embedded into an MCU program in a radio frequency module to be measured, radio frequency signals with different amplitudes within a full range which can be processed by a radio frequency signal source to a radio frequency module input module are sequentially subjected to amplifier and AD conversion, and then an AD sampling value of the radio frequency signals is transmitted to a PC end through a serial port by the MCU, so that a corresponding relation table of signal amplitudes and the AD sampling values is obtained;

2) And (3) data curing: as shown in fig. 2, a read/write command for communication with a computer is embedded in an MCU program inside the radio frequency module. When a writing command is input by a computer, writing data into a nonvolatile memory in the MCU; when a read command is input, reporting data in a nonvolatile memory in the MCU to a computer; after converting the AD sampling value obtained in the step 1) into 16 system, writing a corresponding relation table of the signal amplitude and the AD sampling value into a nonvolatile memory in the MCU by inputting a command into a computer, and completing data solidification;

the method specifically comprises the following steps: and sorting the measurement data (namely, a corresponding relation table of signal amplitude and AD sampling value) and extracting key information. Since the signal amplitude decreases with the rule of 2dB, the signal amplitude of the starting point is key information, and then the number of the amplitude (namely the number of the AD sampling values) and the AD sampling value corresponding to each amplitude are added; these key information are then sent to the MCU in the designed command format.

The above measurement data in table 1 in the background art is exemplified, and since it is most convenient for a computer to process 16-system data, 10-system AD sampling values are converted into 16-system numbers, see table 2:

table 2 conversion of AD sample values from 10 to 16

Table 2 has a total of 26 AD samples, i.e. 26 measurement points, each of which is an integer, and can be represented by a 16-bit unsigned number. The signal amplitude of the starting point is 0dBm, and the computer is most convenient to store the integer considering that the signal amplitude is possibly negative and/or has 1 decimal, so the amplitude of the starting point is enlarged by 10 times to be convenient to store, and can be expressed by a 16-digit signed number, and then divided by 10 for restoration in the process of calculation. The number of the AD sampling values is second key information, and then 26 AD sampling values are obtained, and the core data are further organized into:

TABLE 3 key information after finishing

The data are combined two by two, and the data are written into the nonvolatile memory inside the MCU by inputting commands into the computer, as shown in FIG. 3, the command flash w 000x0000001a represents that the starting point signal amplitude and the AD sampling value are combined into 32-bit number 0x0000001a and then written into the offset 0 of the page 0, and all the data are written in sequence, thus completing the solidification.

The data of page 0 can be read out by commanding flash r 0 to check whether the writing is correct, as shown in fig. 4.

3) Automatic calculation: after the MCU program is started, the corresponding relation table of the signal amplitude and the AD sampling value stored in the internal nonvolatile memory is read out while the AD sampling value of any signal input to the radio frequency module is periodically read, and the corresponding signal amplitude of the AD sampling value of the input signal in the relation table is found out by using a halving search method.

For example, see table 4, with the data in table 3.

Table 4AD sample values and corresponding signal amplitudes

Index	0	1	2	3	4	5	......	12	......	25
											AD sampling value	1010	986	961	936	912	887	......	715	......	455
Signal amplitude	0	-2	-4	6	8	-10	......	-24	......	50

The binary search method is a search method with a time complexity of O (logn), and generally requires that the search sequence be ordered, and in the following, taking the descending order of table 4 as an example, since the counting in the computer generally starts from 0, the indexes of 26 AD sampling values are sequentially 0 to 25.

The method for finding out the signal amplitude corresponding to the AD sampling value of the input signal in the relation table by using the halving search method comprises the following specific steps:

3-1) two variables left and right are set for recording the index range of the lookup. Wherein left initially records the index of the first AD sample value, namely 0; right initially records the index of the last AD sample value, i.e. 25; each search compares the AD sample value of mid = (left + right)/(2) with the search value;

3-2) if the lookup value is greater than or equal to the intermediate value, indicating that the lookup value is positioned on the left of the intermediate value, setting right as mid-1, and setting the range to be searched next time to be positioned in the interval of the index [ left, mid-1 ];

3-3) if the search value is less than the intermediate value, indicating that the search value is positioned on the right of the intermediate value, setting left as mid+1, and setting the range to be searched next time to be positioned in the interval of the index [ mid+1, right ];

3-6) if left is the last index value plus 1, in this case 26, it indicates that the search value is smaller than the AD sample value corresponding to index 25, indicating that the signal amplitude is smaller than the amplitude represented by the last AD sample value, in this case-50 dBm, indicating that the signal is in a no-signal state; otherwise, the search value is between the AD sampling value with index right and the AD sampling value with index left, that is, the signal amplitude is between the amplitude with index right and the amplitude with index left, at this time, left is 1 greater than right, at this time, the change of the signal amplitude in the interval is very small, and the amplitude in the interval and the AD sampling value can be considered to be in a linear relationship to perform linear calculation, and because the interval is very small, the error will also be very small.

For example, in table 4, it is assumed that the AD sample value to be found is 1000.

For the first lookup, left=0, right=25, mid= (0+25)/(2=12), the AD sample value of index 12 is 715, since 1000>715, the lookup value is to the left of the middle;

performing a second search, right=12-1=11, left is still 0, mid= (0+11)/(2=5), the AD sample value of index 5 is 887, and the search value is to the left of the middle value due to 1000> 715;

performing a third search, right=5-1=4, left is still 0, mid= (0+4)/(2=2), the AD sample value of index 2 is 961, and the search value is to the left of the middle value because 1000> 961;

performing a fourth search, right=2-1=1, left is still 0, mid= (0+1)/(2=0), the AD sample value of index 0 is 1010, the search value is to the right of the middle value due to 1000< 1010;

performing a fifth search, left=0+1=1, right is still 1, mid= (1+1)/(2=1), the AD sample value of index 1 is 986, and the search value is to the left of the middle value due to 1000> 986;

the sixth search is performed with left still 1, right=1-1=0, at which time left > right, search is completed, and as expected, the search value 1000 is between the AD sample value of index right and the AD sample value of index left, and in this interval, the amplitude can be considered to be linear with the AD sample value, and the signal amplitude= -2+2+.v. (1010-986) × (1000-986) ≡0.8, and obviously, the algorithm accuracy and efficiency can be guaranteed.

In summary, through the three steps, the automatic detection of the amplitude of the radio frequency signal is realized.

In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.

The principles and embodiments of the present application have been described herein with reference to specific examples, the description of which is intended only to assist in understanding the methods of the present application and the core ideas thereof; also, it is within the scope of the present application to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the application.