CN112557868A - Return loss detection method, calibration method, return loss detection device and system - Google Patents
Return loss detection method, calibration method, return loss detection device and system Download PDFInfo
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Abstract
The application discloses a return loss detection method, a calibration method, a return loss detection device and a return loss detection system, wherein the method comprises the steps of obtaining a frequency domain voltage value of a current incident signal and a frequency domain voltage value of a current reflected signal; obtaining a current incident power value by using a frequency domain voltage value of a current incident signal and a prestored forward power voltmeter, wherein the forward power voltmeter comprises at least one incident power value and a frequency domain voltage value corresponding to the incident power value; obtaining a current reflection power value by using a frequency domain voltage value of a current reflection signal and a prestored reverse power voltmeter, wherein the reverse power voltmeter comprises at least one reflection power value and a frequency domain voltage value corresponding to the reflection power value; and obtaining a return loss value according to the current incident power value and the current reflection power value. By means of the mode, detection errors can be reduced, and stability of return loss detection is improved.
Description
Technical Field
The present application relates to the field of communications technologies, and in particular, to a return loss detection method, a calibration method, a return loss detection apparatus, and a return loss detection system.
Background
The current radio frequency index needs to be tested in the manufacturing process of the filter, and VSWR (Voltage Standing Wave Ratio) alarm detection can be performed aiming at the VSWR (Voltage Standing Wave Ratio) condition of an active part capable of monitoring a product in real time. Due to differences of a Printed Circuit Board Assembly (PCBA), diversity of Radio Frequency (RF) signals, and different modulation modes, technicians have difficulty in obtaining accurate power, and the power obtained in practical application is very unstable, which greatly affects performance indexes of products and cannot meet requirements of customers.
The prior art methods for obtaining power include: deriving a calculation formula of voltage and power according to a technical document, and directly applying the calculation formula to obtain a corresponding power value in subsequent products to calculate a return loss value, wherein the method requires the given calculation formula to be very accurate and can adapt to all conditions (such as temperature change), and the method meets the requirements under most conditions, but the conditions of instability can occur in the processing process because the sampling precision and the temperature are influenced and the formula is derived by a radio frequency engineer and is not provided in an actual document; another way is to make a voltage and power correspondence table under a certain carrier mode for later searching, because there is only one correspondence table, the way can be used under the condition of single signal and simple modulation mode, when the detected signal changes its modulation mode, the way has too large deviation and is very unstable, if a correspondence table is made for each modulation mode separately, a large amount of flash memory space is occupied, and at the same time, it is necessary to find out which modulation mode the currently transmitted signal belongs to before checking the table each time, so that a new way is added to confirm the modulation mode of the signal, and the technical difficulty and hardware cost of the product are increased.
Disclosure of Invention
The application mainly solves the problem of providing a return loss detection method, a calibration method, a return loss detection device and a return loss detection system, which can reduce detection errors and improve the stability of return loss detection.
In order to solve the technical problem, the technical scheme adopted by the application is as follows: the method comprises the steps of obtaining a frequency domain voltage value of a current incident signal and a frequency domain voltage value of a current reflected signal; obtaining a current incident power value by using a frequency domain voltage value of a current incident signal and a prestored forward power voltmeter, wherein the forward power voltmeter comprises at least one incident power value and a frequency domain voltage value corresponding to the incident power value; obtaining a current reflection power value by using a frequency domain voltage value of a current reflection signal and a prestored reverse power voltmeter, wherein the reverse power voltmeter comprises at least one reflection power value and a frequency domain voltage value corresponding to the reflection power value; and obtaining a return loss value according to the current incident power value and the current reflection power value.
In order to solve the technical problem, the technical scheme adopted by the application is as follows: a calibration method is provided, the method comprising: acquiring incident power values and corresponding frequency domain voltage values of different incident signals; establishing a forward power voltmeter according to the incident power value and the frequency domain voltage value of the incident signal, wherein the forward power voltmeter comprises at least one incident power value and a frequency domain voltage value corresponding to the incident power value; acquiring reflection power values and corresponding frequency domain voltage values of different reflection signals, wherein the reflection signals correspond to incident signals; and establishing a reverse power voltmeter according to the reflection power value and the frequency domain voltage value of the reflection signal, wherein the reverse power voltmeter comprises at least one reflection power value and a frequency domain voltage value corresponding to the reflection power value.
In order to solve the above technical problem, another technical solution adopted by the present application is: the return loss detection device comprises an acquisition circuit and a processing circuit which are connected with each other, wherein the acquisition circuit is used for acquiring the frequency domain voltage value of the current incident signal and the frequency domain voltage value of the current reflected signal; the processing circuit is used for obtaining a current incident power value by utilizing a frequency domain voltage value of a current incident signal and a prestored forward power voltmeter, wherein the forward power voltmeter comprises at least one incident power value and a frequency domain voltage value corresponding to the incident power value; obtaining a current reflection power value by using a frequency domain voltage value of a current reflection signal and a prestored reverse power voltmeter, wherein the reverse power voltmeter comprises at least one reflection power value and a frequency domain voltage value corresponding to the reflection power value; and obtaining a return loss value according to the current incident power value and the current reflection power value.
In order to solve the above technical problem, another technical solution adopted by the present application is: the return loss detection system comprises a power meter, a test device and a return loss detection device which are sequentially connected, wherein the power meter is used for sending an incident power value and a reflected power value to the test device, the test device is used for receiving and processing the incident power value and the reflected power value, and the return loss detection device is the return loss detection device.
Through the scheme, the beneficial effects of the application are that: pre-establishing a corresponding relation between the incident power value and the corresponding frequency domain voltage value, and establishing a corresponding relation between the reflection power value and the corresponding frequency domain voltage value; the current transmitting/reflecting power value can be obtained by utilizing a forward/reverse power voltmeter, and the return loss of the return loss detection device can be monitored in real time; under different radio frequency and modulation modes, stable frequency domain voltage values can be obtained, and the problem of false alarm caused by unstable return loss under different modulation modes is solved; for each return loss detection device, each frequency band can correspond to a forward power voltmeter and a reverse power voltmeter instead of using a common meter, so that detection errors are reduced; and because the power detection problem is solved from software, hardware does not need to be added.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts. Wherein:
fig. 1 is a schematic structural diagram of an embodiment of a return loss detection apparatus provided in the present application;
fig. 2 is a schematic flow chart of an embodiment of a return loss detection method provided in the present application;
fig. 3 is a schematic flow chart of another embodiment of a return loss detection method provided in the present application;
FIG. 4 is a schematic flow chart diagram illustrating an embodiment of a calibration method provided herein;
FIG. 5 is a schematic diagram of an embodiment of a return loss detection system provided herein;
FIG. 6 is a schematic diagram of the structure for obtaining the incident power value in FIG. 4;
fig. 7 is a schematic diagram of the structure for obtaining the reflection power value in fig. 4.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Referring to fig. 1, fig. 1 is a schematic structural diagram of an embodiment of a return loss detection apparatus 10 provided in the present application, where the return loss detection apparatus 10 includes an acquisition circuit 11 and a processing circuit 12 connected to each other, and the return loss detection apparatus 10 may be a filter.
The obtaining circuit 11 is configured to obtain a frequency domain voltage value of a current incident signal and a frequency domain voltage value of a current reflected signal; specifically, the obtaining circuit 11 may be a detection chip, and the detection chip may receive a radio frequency signal sent by an external device, and measure the power of the radio frequency signal to obtain a time domain voltage value of the radio frequency signal, where the radio frequency signal includes an incident signal and a reflected signal.
The processing circuit 12 is configured to obtain a current incident power value by using a frequency domain voltage value of a current incident signal and a pre-stored forward power voltmeter, where the forward power voltmeter includes at least one incident power value and a frequency domain voltage value corresponding to the incident power value; obtaining a current reflection power value by using a frequency domain voltage value of a current reflection signal and a prestored reverse power voltmeter, wherein the reverse power voltmeter comprises at least one reflection power value and a frequency domain voltage value corresponding to the reflection power value; and obtaining a return loss value according to the current incident power value and the current reflection power value.
In practical application, the return loss detection apparatus 10 may query the forward power voltmeter by using the frequency domain voltage value of the current incident signal, so as to obtain an incident power value corresponding to the current frequency domain voltage value; similarly, the return loss detection apparatus 10 uses the frequency domain voltage value of the current reflection signal to perform query in the reverse power voltmeter, so as to obtain the reflection power value corresponding to the current frequency domain voltage value; after the current incident power value and the current reflection power value are obtained, the current reflection power value and the current incident power value can be compared and expressed in a logarithmic mode, and therefore the return loss value is calculated.
Return loss detection device 10 in this embodiment need not to distinguish which kind of modulation mode the signal belongs to, and adaptability is wide, to every return loss detection device 10, and every frequency channel can correspond a forward power voltmeter and reverse power voltmeter, and not use public table, is favorable to reducing detection error, still can utilize stable forward power voltmeter and reverse power voltmeter, solves the unstable problem of return loss detection.
Referring to fig. 2, fig. 2 is a schematic flowchart illustrating an embodiment of a return loss detection method according to the present application, the method including:
step 21: and acquiring the frequency domain voltage value of the current incident signal and the frequency domain voltage value of the current reflected signal.
The return loss detection device comprises a detection chip, wherein the detection chip can receive an incident signal and a reflected signal sent by external equipment, and measures the power of the incident signal and the reflected signal to obtain a corresponding time domain voltage value.
Step 22: and obtaining the current incident power value by using the frequency domain voltage value of the current incident signal and a prestored forward power voltmeter.
In order to calculate the return loss value quickly and accurately in practical application, a prestored forward power voltmeter which comprises at least one incident power value and a frequency domain voltage value corresponding to the incident power value can be utilized.
In a specific embodiment, the return loss detection device may receive an incident power value of at least one incident signal sent by the external device and a frequency domain voltage value corresponding to the incident power value, and then establish a mapping relationship between the incident power value and the frequency domain voltage value to form a forward power voltmeter and store the forward power voltmeter.
In another specific embodiment, the return loss detection device can directly receive and store a forward power voltmeter sent by an external device.
The return loss detection device utilizes the frequency domain voltage value of the current incident signal to inquire in a forward power voltmeter stored in the return loss detection device, so that the incident power value matched with the frequency domain voltage value of the current incident signal is obtained.
Step 23: and obtaining the current reflection power value by using the frequency domain voltage value of the current reflection signal and a prestored reverse power voltmeter.
The reverse power voltmeter comprises at least one reflection power value and a frequency domain voltage value corresponding to the reflection power value.
In a specific embodiment, the return loss detection device may receive a reflection power value of at least one reflection signal sent by the external device and a frequency domain voltage value corresponding to the reflection power value, and then establish a mapping relationship between the reflection power value and the frequency domain voltage value to form a reverse power voltmeter and store the reverse power voltmeter.
In another specific embodiment, the return loss detection device can directly receive and store a reverse power voltmeter sent by an external device.
In practical application, the return loss detection device uses the frequency domain voltage value of the current reflected signal to query in a reverse power voltmeter stored in the return loss detection device, so as to obtain the reflected power value matched with the frequency domain voltage value of the current reflected signal.
Step 24: and obtaining a return loss value according to the current incident power value and the current reflection power value.
And comparing the current reflection power value with the current incident power value to calculate the return loss value.
In the radio frequency return loss calculation, because the circuit uses the difference of material and signal transmission mode, the situation that the power reaches a stability is difficult, the performance of the product is limited, the common algorithm can not adapt to multiple scenes, the return loss detection method in the embodiment solves the power detection problem from software, hardware does not need to be added, which modulation mode the signal belongs to does not need to be distinguished, the adaptability is wide, each return loss detection device can correspond to a forward power voltmeter and a reverse power voltmeter, but does not use a public meter, the detection error is favorably reduced, and because the corresponding relation between the frequency domain voltage value and the power value is established in advance, the return loss value can be rapidly and accurately calculated in the actual use, the frequency domain voltage value is more stable than the time domain voltage value, and the problem that the return loss detection is unstable can be solved.
Referring to fig. 3, fig. 3 is a schematic flow chart of another embodiment of a return loss detection method provided in the present application, the method including:
step 31: the method comprises the steps of receiving an incident signal, measuring the voltage of the incident signal to obtain a time domain voltage value of the incident signal, and performing fast Fourier transform on the time domain voltage value of the incident signal to obtain a frequency domain voltage value of the incident signal.
Sampling an incident signal within a first preset time to obtain a plurality of time domain voltage values of the incident signal; and carrying out fast Fourier transform on a plurality of time domain voltage values of the incident signal to obtain frequency domain voltage values of the incident signal.
Step 32: and receiving the reflected signal, measuring the voltage of the reflected signal to obtain a time domain voltage value of the reflected signal, and performing fast Fourier transform on the time domain voltage value of the reflected signal to obtain a frequency domain voltage value of the reflected signal.
Sampling the reflected signal within a second preset time to obtain a plurality of time domain voltage values of the reflected signal; and carrying out fast Fourier transform on the plurality of time domain voltage values of the reflected signals to obtain frequency domain voltage values of the reflected signals.
Step 33: and obtaining the current incident power value by using the frequency domain voltage value of the current incident signal and a prestored forward power voltmeter.
Step 34: and obtaining the current reflection power value by using the frequency domain voltage value of the current reflection signal and a prestored reverse power voltmeter.
Step 35: and obtaining a return loss value according to the current incident power value and the current reflection power value.
The method comprises the steps of carrying out fast Fourier transform on a plurality of sampled time domain data to obtain frequency domain data, establishing a power voltmeter, looking up a table according to actual frequency domain voltage values to obtain corresponding power values, greatly improving sampling precision, ensuring detection stability without considering which signals and which modulation modes are currently detected, and simultaneously establishing a stable table corresponding to power and voltage to solve the problem of unstable return loss.
Referring to fig. 4, fig. 4 is a schematic flowchart illustrating an embodiment of a calibration method provided in the present application, the method including:
step 41: and acquiring incident power values and corresponding frequency domain voltage values of different incident signals.
And receiving the incident power value of the incident signal, acquiring the time domain voltage value of the incident signal, and performing fast Fourier transform on the time domain voltage value of the incident signal to obtain the frequency domain voltage value of the incident signal.
Step 42: and establishing a forward power voltmeter according to the incident power value and the frequency domain voltage value of the incident signal.
The forward power voltmeter comprises at least one incident power value and a frequency domain voltage value corresponding to the incident power value; specifically, the return loss detection device may receive at least one incident power value sent by the external device and a frequency domain voltage value of an incident signal corresponding to the incident power value, establish a correspondence between the incident power value and the frequency domain voltage value, and form a forward power voltmeter.
Step 43: and acquiring the reflection power values of different reflection signals and corresponding frequency domain voltage values.
The reflected signal corresponds to the incident signal, receives the reflection power value of the reflected signal, acquires the time domain voltage value of the reflected signal, and performs fast Fourier transform on the time domain voltage value of the reflected signal to obtain the frequency domain voltage value of the reflected signal.
Step 44: and establishing a reverse power voltmeter according to the reflection power value and the frequency domain voltage value of the reflection signal.
The reverse power voltmeter comprises at least one reflection power value and a frequency domain voltage value corresponding to the reflection power value; specifically, the return loss detection device may further receive at least one reflection power value sent by the external device and a frequency domain voltage value of the reflection signal corresponding to the reflection power value, and establish a correspondence between the reflection power value and the frequency domain voltage value to form a reverse power voltmeter.
Referring to fig. 5, fig. 5 is a schematic structural diagram of an embodiment of a return loss detection system according to the present application, in which the return loss detection system 100 includes a power meter 20, a testing device 30, and a return loss detection apparatus 10, which are connected in sequence, the power meter 20 is configured to send an incident power value and a reflected power value to the testing device 30, the testing device 30 is configured to receive the incident power value and the reflected power value, and perform processing, and the return loss detection apparatus 10 is the return loss detection apparatus in the above embodiment.
In a specific embodiment, the testing device 30 is configured to send the received incident power value and the received reflected power value to the return loss detection apparatus 10, and the return loss detection apparatus 10 is configured to obtain a frequency domain voltage value of the incident signal and a frequency domain voltage value of the reflected signal, establish a forward power voltmeter according to the incident power value and the frequency domain voltage value of the incident signal, and establish a reverse power voltmeter according to the reflected power value and the frequency domain voltage value of the reflected signal.
With reference to fig. 5, the return loss detection system 100 of the present embodiment further includes a testing device 30 and a signal source 40 connected to each other, wherein both the testing device 30 and the signal source 40 are connected to the return loss detection apparatus 10; the test apparatus 30 controls the signal source 40 to output the incident signal at a preset power step value within a preset power range.
The communication between test equipment 30 and signal source 40 may employ standard protocols; the size of the preset power stepping value can be set according to the requirements of specifications, if the error range is small, the size of the preset power stepping value is reduced when a power voltmeter is made, and meanwhile, the preset power stepping value cannot be set too small in consideration of production efficiency and occupied space of codes; specifically, the output frequency, the carrier mode, and the output power value of the signal source 40 may be set, the testing device 30 may be a computer, the computer is connected to the return loss detection device 10 through a data line, the input power value of the return loss detection device 10 may be 15-50dB, the preset power step value is 0.5dB, and the computer controls the return loss detection device 10 to output the incident signal with the initial power value of 15dB and the interval of 0.5dB, that is, sequentially output the incident signals with the power values of 15dB, 15.5dB, … …, and 50 dB.
Because the power value output by the signal source 40 is relatively small, for example, less than 15dBm, but the input power required by the return loss detection device 10 is generally relatively large, for example, greater than 48dBm, and power amplification is required, the return loss detection device 10 further includes a power amplifier 50, the power amplifier 50 is respectively connected with the return loss detection device 10 and the signal source 40 through RF lines, and the signal source 40 and the power amplifier 50 can be turned on when in use; the signal source 40 outputs an incident signal after receiving the control signal sent by the testing device 30, and outputs a radio frequency signal to the power amplifier 50.
The power amplifier 50 amplifies the radio frequency signal and outputs the amplified radio frequency signal to the return loss detection apparatus 10.
In a specific embodiment, as shown in fig. 6, when obtaining the incident power value, the return loss detection apparatus 10 includes a first port connected to the power amplifier 50 and a second port connected to the power meter 20, the rf signal output by the power amplifier 50 is output to the first port of the return loss detection apparatus 10, the first port may be a TX (incident) port, and the second port is an ANT (antenna) port; in order to reduce the radiation of the rf signal, a load 60 may be connected to the output of the return loss detection apparatus 10, or an attenuator (not shown) may be connected to the output of the power amplifier 50, and then connected to the load 60.
The return loss detection device 10 receives the incident power value sent by the test equipment 30, the power meter 20 is connected with the test equipment 30 through an RF line, and a standard protocol can be adopted for communication between the test equipment 30 and the power meter 20; the power meter 20 measures the power of the rf signal output from the second port of the return loss detection apparatus 10 to obtain an incident power value, and feeds back the incident power value to the test device 30.
In order to obtain an accurate incident power value, the testing device 30 may obtain the incident power value after the value of the power meter 20 is stable, for example, the testing device 30 may delay to read the incident power value by 100 ms; after the testing device 30 obtains the stable incident power value, it can be determined whether the incident power value fed back by the power meter 20 meets the preset power requirement; if the incident power value fed back by the power meter 20 meets the preset power requirement, the step of sending the incident power value to the return loss detection device 10 by the test equipment 30 is executed.
If the incident power value fed back by the power meter 20 does not meet the preset power requirement, determining whether the adjustment times is greater than the preset adjustment times, where the preset adjustment times may be 5 times; if the adjustment times are not greater than the preset adjustment times, controlling the signal source 40 to adjust the incident power value; if the adjustment times are greater than the preset adjustment times, the return loss detection process is exited, or the step value of the power adjustment can be changed to quickly reach the standard of the preset power.
The test device 30 may read the value of the power meter 20 after setting the minimum power of the signal source 40 to form a dynamic feedback, so that the power input to the return loss detection apparatus 10 meets a preset power requirement, such as 15 dBm; when the incident power value reaches a stable value, the test equipment 30 sends the value of the power meter 20 to the return loss detection device 10 through the communication protocol.
The return loss detection device 10 obtains a time domain voltage value of an incident signal generated by the signal source, and performs fast fourier transform on the time domain voltage value to obtain a frequency domain voltage value of the incident signal.
In a specific embodiment, the return loss detection apparatus 10 first samples the signal output by the power amplifier 50 within a predetermined time to obtain a plurality of time domain voltage values.
Specifically, according to the RF signal and the sampling theorem, the sampling time must be kept at 2T (T is the period of the signal) to ensure that all data is taken, and the number of voltages sampled in the time period 2T can be calculated according to the sampling accuracy of the chip used by the return loss detection apparatus 10. In order to reduce the calculation pressure of an MCU (micro controller Unit) (not shown in the figure) in the return loss detection apparatus 10, the number of sampling points is an exponential power of 2, because an FFT (Fast Fourier transform) algorithm is used.
The return loss detection device 10 can perform fast fourier transform on a plurality of time domain voltage values to obtain frequency domain voltage values; for example, suppose that 2048 time domain voltage values can be sampled at most in a time period 2T, the 2048 time domain voltage values are processed by FFT to obtain voltage values in a frequency domain, and only a real component is taken to obtain voltage values in the frequency domain; the use of FFT transforms can discard unwanted white noise in the sampled signal and can be considered a filtering process.
In the prior art, different filtering algorithms are required for obtaining stable power, such as an amplitude limiting jitter elimination method, a curve fitting method, a median method, an arithmetic mean method, a first-order lag method, a weighted recursive mean method, and an IIR (Infinite Impulse Response) digital filter; the embodiment adopts the frequency domain voltage value, is relatively stable and does not need to use a filtering algorithm.
The return loss detection device 10 can obtain the current frequency domain voltage value through FFT, and at the same time, the return loss detection device 10 can obtain the power value of the power meter 20, store the frequency domain voltage value and the incident power value into the forward power voltmeter, and sequentially change the power values output by the signal source 40, so as to form a complete forward power voltmeter.
The return loss detection device 10 establishes a forward power voltmeter according to the incident power value and the frequency domain voltage value of the incident signal; the frequency domain voltage value is a digital voltage, and the unit of the power value stored in the forward power voltmeter is mW due to the nonlinear characteristic of the power value (dBm); the obtained frequency domain voltage value may fall within a certain interval of a forward power voltmeter, and due to the fact that the actual power value has a power error range, a corresponding power value (mW) is obtained between discrete frequency domain voltage values by using a linear algorithm, and then the power value (mW) is converted into a power value (dBm). For example, the two power values are 35dBm and 35.5dBm, which correspond to frequency domain voltage values of 478 and 502, respectively; if the currently acquired frequency domain voltage value is 495, firstly, 35dBm and 35.5dBm are converted into power values (mW) which are recorded as a and B to obtain points (478, a) and points (502, B), a linear equation is obtained according to the two points, the frequency domain voltage value 495 is substituted for calculation to obtain the power value (mW), and then unit conversion is carried out to obtain the power value (dBm).
The test device 30 may determine whether the forward power voltmeter is completed, and if the forward power voltmeter is not completed, continue to establish the forward power voltmeter until all power values within the preset power range and corresponding frequency domain voltage values are obtained; if the forward power voltmeter is completed, the power meter 20 measures the power of the radio frequency signal input to the second port to obtain a reflection power value, and feeds back the reflection power value to the test equipment.
As shown in fig. 7, different from the obtaining of the incident power value, when obtaining the reflected power value, the return loss detection apparatus 10 includes a first port connected to the load 60 and a second port connected to the power meter 20, and the specific implementation manner thereof is similar to the obtaining of the forward power voltmeter, and is not described herein again.
The test equipment 30 sends the reflection power value to the return loss detection device 10; the return loss detection device 10 obtains a plurality of time domain voltage values of the radio frequency signal input to the second port, and performs fast fourier transform on the plurality of time domain voltage values to obtain a frequency domain voltage value of the reflected signal.
The signal output by the power amplifier 50 enters the second port of the return loss detection device 10, and reaches the first port from the second port, and the power meter 20 can measure the power value of the second port of the return loss detection device 10, where the power value of the second port is the reflection power value; and simultaneously sampling the radio-frequency signal input to the second port to obtain a plurality of time domain point voltage values, and then obtaining corresponding frequency domain voltage values by utilizing FFT (fast Fourier transform).
In order to ensure the accuracy of the return loss calculation, the sampling time interval between two voltage sampling interfaces in the MCU can be reduced as much as possible during sampling, and sampling can be performed simultaneously, so that there is no phase delay, for example, an ADC (Analog to Digital Converter) parallel module can be used.
The return loss detection device 10 establishes a reverse power voltmeter according to the reflection power value and the frequency domain voltage value of the reflection signal.
The embodiment comprises two parts: and automatically making a power voltmeter and searching, and after the forward power voltmeter and the reverse power voltmeter are obtained, in practical application, searching a corresponding power value according to the current frequency domain voltage value, and calculating a return loss value.
The return loss detection device 10 obtains a current incident power value according to the forward power voltmeter and the frequency domain voltage value of the current incident signal, and obtains a current reflected power value according to the reverse power voltmeter and the frequency domain voltage value of the current reflected signal; and then obtaining a return loss value according to the current incident power value and the current reflection power value.
In practical application, the coupling signal is presented to the outside through a detection chip (not shown in the figure) as a frequency domain voltage value in a power voltmeter; when the radio-frequency signal is monitored in real time, a frequency domain voltage value is obtained by adopting an FFT algorithm, a power value corresponding to the frequency domain voltage value is searched in a power voltmeter, so that a current incident power value and a current reflection power value are obtained, and a return loss value is calculated in real time.
In another specific embodiment, the testing device 30 is configured to receive the frequency domain voltage value of the incident signal and the frequency domain voltage value of the reflected signal sent by the return loss detecting apparatus 10, and establish a forward power voltmeter according to the incident power value and the frequency domain voltage value of the incident signal, and establish a reverse power voltmeter according to the reflected power value and the frequency domain voltage value of the reflected signal; the return loss detection apparatus 10 is configured to receive the forward power voltmeter and the reverse power voltmeter sent by the test device 30, and other operations are similar to those in the above embodiments, and are not described herein again.
In the embodiment, in order to improve the calculation accuracy, each return loss detection device 10 can be independently used as a power voltmeter without using a common meter, so that errors are reduced, the errors comprise errors caused by PCBA differences, and calculation errors of power values obtained by converting digital voltages into analog voltages and looking up the table of the analog voltages, the stability and the accuracy of obtaining the incident power values and the reflected power values are ensured, and false alarms are avoided; in addition, when the return loss detection device 10 uses a chip without a DSP (Digital Signal Processor), the floating point operation of the code can be reduced by using a table lookup; the automatic tabulation mode reduces the workload of programmers, can properly reduce the performance requirement of the detection chip, and can eliminate the conversion error of the detection chip by tabulation.
In the several embodiments provided in the present application, it should be understood that the disclosed method and apparatus may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, a division of modules or units is merely a logical division, and an actual implementation may have another division, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed.
Units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.
In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The above embodiments are merely examples, and not intended to limit the scope of the present application, and all modifications, equivalents, and flow charts using the contents of the specification and drawings of the present application, or those directly or indirectly applied to other related arts, are included in the scope of the present application.
Claims (10)
1. A return loss detection method, comprising:
acquiring a frequency domain voltage value of a current incident signal and a frequency domain voltage value of a current reflected signal;
obtaining a current incident power value by using the frequency domain voltage value of the current incident signal and a prestored forward power voltmeter, wherein the forward power voltmeter comprises at least one incident power value and a frequency domain voltage value corresponding to the incident power value;
obtaining a current reflection power value by using the frequency domain voltage value of the current reflection signal and a prestored reverse power voltmeter, wherein the reverse power voltmeter comprises at least one reflection power value and a frequency domain voltage value corresponding to the reflection power value;
and obtaining a return loss value according to the current incident power value and the current reflection power value.
2. The return loss detection method according to claim 1, further comprising:
receiving the incident signal, measuring the voltage of the incident signal to obtain a time domain voltage value of the incident signal, and performing fast Fourier transform on the time domain voltage value of the incident signal to obtain a frequency domain voltage value of the incident signal;
and receiving the reflected signal, measuring the voltage of the reflected signal to obtain a time domain voltage value of the reflected signal, and performing fast Fourier transform on the time domain voltage value of the reflected signal to obtain a frequency domain voltage value of the reflected signal.
3. The return loss detection method according to claim 2, further comprising:
sampling the incident signal within a first preset time to obtain a plurality of time domain voltage values of the incident signal;
carrying out fast Fourier transform on a plurality of time domain voltage values of the incident signal to obtain frequency domain voltage values of the incident signal;
sampling the reflection signal within a second preset time to obtain a plurality of time domain voltage values of the reflection signal;
and carrying out fast Fourier transform on the plurality of time domain voltage values of the reflection signals to obtain frequency domain voltage values of the reflection signals.
4. The return loss detection method according to claim 1,
the forward power voltmeter and the reverse power voltmeter are transmitted by an external device or generated by the external device.
5. A calibration method, characterized in that the method comprises:
acquiring incident power values and corresponding frequency domain voltage values of different incident signals;
establishing a forward power voltmeter according to the incident power value and the frequency domain voltage value of the incident signal, wherein the forward power voltmeter comprises at least one incident power value and a frequency domain voltage value corresponding to the incident power value;
acquiring reflection power values and corresponding frequency domain voltage values of different reflection signals, wherein the reflection signals correspond to the incident signals;
and establishing a reverse power voltmeter according to the reflection power value and the frequency domain voltage value of the reflection signal, wherein the reverse power voltmeter comprises at least one reflection power value and a frequency domain voltage value corresponding to the reflection power value.
6. The calibration method according to claim 5, further comprising:
receiving an incident power value of the incident signal, acquiring a time domain voltage value of the incident signal, and performing fast Fourier transform on the time domain voltage value of the incident signal to obtain a frequency domain voltage value of the incident signal;
and receiving the reflection power value of the reflection signal, acquiring the time domain voltage value of the reflection signal, and performing fast Fourier transform on the time domain voltage value of the reflection signal to obtain the frequency domain voltage value of the reflection signal.
7. A return loss detection device is characterized by comprising an acquisition circuit and a processing circuit which are connected with each other,
the acquisition circuit is used for acquiring the frequency domain voltage value of the current incident signal and the frequency domain voltage value of the current reflected signal;
the processing circuit is used for obtaining a current incident power value by using the frequency domain voltage value of the current incident signal and a prestored forward power voltmeter, wherein the forward power voltmeter comprises at least one incident power value and a frequency domain voltage value corresponding to the incident power value; obtaining a current reflection power value by using the frequency domain voltage value of the current reflection signal and a prestored reverse power voltmeter, wherein the reverse power voltmeter comprises at least one reflection power value and a frequency domain voltage value corresponding to the reflection power value; and obtaining a return loss value according to the current incident power value and the current reflection power value.
8. A return loss detection system comprising a power meter, a test device, and a return loss detection apparatus, connected in sequence, wherein the power meter is configured to transmit an incident power value and a reflected power value to the test device, the test device is configured to receive the incident power value and the reflected power value, and perform processing, and the return loss detection apparatus is the return loss detection apparatus according to claim 7.
9. The return loss detection system of claim 8,
the test equipment is used for sending the received incident power value and the received reflected power value to the return loss detection device, the return loss detection device is used for obtaining a frequency domain voltage value of an incident signal and a frequency domain voltage value of a reflected signal, establishing a forward power voltmeter according to the incident power value and the frequency domain voltage value of the incident signal, and establishing a reverse power voltmeter according to the reflected power value and the frequency domain voltage value of the reflected signal.
10. The return loss detection system of claim 8,
the test equipment is used for receiving the frequency domain voltage value of the incident signal and the frequency domain voltage value of the reflected signal sent by the return loss detection device, establishing a forward power voltmeter according to the incident power value and the frequency domain voltage value of the incident signal, and establishing a reverse power voltmeter according to the reflected power value and the frequency domain voltage value of the reflected signal; the return loss detection device is used for receiving the forward power voltmeter and the reverse power voltmeter which are sent by the test equipment.
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| CN201910919439.7A CN112557868A (en) | 2019-09-26 | 2019-09-26 | Return loss detection method, calibration method, return loss detection device and system |
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| CN201910919439.7A CN112557868A (en) | 2019-09-26 | 2019-09-26 | Return loss detection method, calibration method, return loss detection device and system |
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