CN117031120A - Device and method for monitoring microwave frequency change and absolute frequency - Google Patents
Device and method for monitoring microwave frequency change and absolute frequency Download PDFInfo
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Abstract
The invention discloses a device and a method for monitoring microwave frequency change and absolute frequency, wherein the device for monitoring microwave frequency change comprises a first power dividing module, a first microwave interferometer and a second microwave interferometer, wherein the detected microwave signal is divided into two paths, the two arms of the first microwave interferometer and the second microwave interferometer are respectively provided with time delay unbalance, the time delay unbalance of the second microwave interferometer is longer than the time delay unbalance of the first microwave interferometer by a quarter wavelength of the detected microwave signal, and the quarter wavelength time delay is realized by means of a 90-degree bridge, a microwave phase shifter, a coaxial cable and the like; the power detector receives interference signals output by the first microwave interferometer and the second microwave interferometer, the signals in the power detector change along with sine or cosine functions, and the change corresponds to the microwave frequency information of the detected microwave signals; the invention can rapidly and accurately measure the variation of the microwave frequency; the absolute frequency of the microwaves can be measured by the device after the third microwave interferometer with smaller delay is introduced.
Description
Technical Field
The invention belongs to the field of microwave frequency measurement, and particularly relates to a device and a method for monitoring microwave frequency change and absolute frequency.
Background
The monitoring of microwave frequency information has wide applications such as microwave frequency control, microwave frequency analysis, microwave frequency domain measurement, and chirped wave radar. In these applications, it is important, and even crucial, to accurately measure or obtain high resolution, large range and high speed microwave frequency variation information. The measurement of microwave or RF frequency information can be achieved by many different methods, such as down-converting a high-frequency signal and obtaining information of the frequency variation through fast fourier transform, but this method requires a proper local signal, which also puts higher demands on the isolation and bandwidth of the mixer, and also puts greater challenges on the sampling rate of the acquisition card when demodulating higher frequency variation, so that the above-mentioned method of frequency measurement has certain disadvantages in the frequency measurement range, frequency measurement resolution and frequency measurement speed.
Disclosure of Invention
The invention aims to: the invention aims to provide a device and a method for monitoring real-time change and absolute frequency of microwave frequency, which are high in speed and high in precision.
The technical scheme is as follows: the device for monitoring the microwave frequency change comprises:
the first power dividing module is used for receiving the detected microwave signal and dividing the detected microwave signal into two paths;
the second power dividing module is used for receiving a first path of microwave signals from the first power dividing module and dividing the first path of microwave signals into two paths which enter two arms of the first microwave interferometer;
the third power dividing module is used for receiving a second path of microwave signals from the first power dividing module and dividing the second path of microwave signals into two paths which enter two arms of the second microwave interferometer;
both arms of the first microwave interferometer and the second microwave interferometer have a delay imbalance, and the delay imbalance of the second microwave interferometer is one-quarter wavelength of the long sounding microwave signal of the first microwave interferometer;
the power detector receives interference signals output by the first microwave interferometer and the second microwave interferometer, and the signals in the power detector change along with a sine function or a cosine function, and the change corresponds to the microwave frequency change information of the detected microwave signals.
Further, the first, second and third power dividing modules are all microwave power dividers or 3dB couplers;
the two arms of the first microwave interferometer and the second microwave interferometer are formed by coaxial cables with different lengths, so that the delay is unbalanced, and the coaxial cable of the second microwave interferometer is longer than the coaxial cable of the first microwave interferometer by a quarter wavelength of a detected microwave signal;
alternatively, the coaxial cable of the second microwave interferometer is equal in length to the coaxial cable of the first microwave interferometer, and either arm of the first microwave interferometer and the second microwave interferometer is coupled to a phase modulator for causing the delay imbalance of the second microwave interferometer to be one-quarter wavelength longer than the delay imbalance of the first microwave interferometer. Further, the first power dividing module is a microwave power divider or a 3dB coupler, any one of the second power dividing module or the third power dividing module is a 90-degree bridge, and the other one is a microwave power divider or a 3dB coupler;
the phase difference between two paths of signals output by the 90-degree bridge is one quarter wavelength of a detected microwave signal;
the two arms of the first microwave interferometer and the second microwave interferometer are formed by coaxial cables with the same length to form delay unbalance.
Further, the first microwave interferometer and the second microwave interferometer each receive and combine the microwave signals of the two arms using a 90 degree bridge to produce two output interference signals.
Based on the same inventive concept, the method for monitoring the microwave frequency variation comprises the following steps:
receiving a detected microwave signal by using a first power dividing module, and dividing the detected microwave signal into two paths;
the second power dividing module is utilized to receive a first path of microwave signals from the first power dividing module, and the first path of microwave signals are divided into two paths to enter two arms of the first microwave interferometer;
receiving a second path of microwave signals from the first power dividing module by utilizing the third power dividing module, and dividing the second path of microwave signals into two paths which enter two arms of a second microwave interferometer;
both arms of the first microwave interferometer and the second microwave interferometer have a delay imbalance, and the delay imbalance of the second microwave interferometer is one-quarter wavelength of the long sounding microwave signal of the first microwave interferometer;
and receiving interference signals output by the first microwave interferometer and the second microwave interferometer by using a power detector, wherein the signals in the power detector change along with a sine function or a cosine function, and the change corresponds to the microwave frequency change information of the detected microwave signals.
Based on the same inventive concept, the device for monitoring the microwave frequency change according to the invention comprises:
the fourth power dividing module is used for receiving the detected microwave signals and dividing the detected microwave signals into four paths, wherein two paths enter two arms of the first microwave interferometer, and the other two paths enter two arms of the second microwave interferometer;
the two arms of the first microwave interferometer and the second microwave interferometer are provided with delay unbalance, and the delay unbalance of the second microwave interferometer is longer than that of the first microwave interferometer by a quarter wavelength of a detected microwave signal;
the power detector receives interference signals output by the first microwave interferometer and the second microwave interferometer, and the signals in the power detector change along with a sine function or a cosine function, and the change corresponds to the microwave frequency change information of the detected microwave signals.
Based on the same inventive concept, the method for monitoring the microwave frequency variation comprises the following steps:
the fourth power dividing module is used for receiving the detected microwave signals and dividing the detected microwave signals into four paths, wherein two paths enter two arms of the first microwave interferometer, and the other two paths enter two arms of the second microwave interferometer;
the two arms of the first microwave interferometer and the second microwave interferometer are provided with delay unbalance, and the delay unbalance of the second microwave interferometer is longer than the delay unbalance of the first microwave interferometer by a quarter wavelength of a microwave signal;
and receiving interference signals output by the first microwave interferometer and the second microwave interferometer by using a power detector, wherein the signals in the power detector change along with a sine function or a cosine function, and the change corresponds to the microwave frequency change information of the detected microwave signals.
Based on the same inventive concept, the method for monitoring the microwave frequency variation comprises the following steps:
the fifth power dividing module is used for receiving the detected microwave signals and dividing the detected microwave signals into two paths; one path is used as a first input signal with long delay, and the other path is used as a second input signal with short delay;
the first input signal is introduced into the delay unbalance delta L through the coaxial cable and then is connected into the sixth power dividing module; the phase difference between the two paths of signals output by the sixth power dividing module is one quarter wavelength of the detected microwave signal;
the second input signal is connected to a seventh power dividing module, and the second input signal is divided into two paths;
the first 90-degree bridge receives a first path of signals output by the sixth power dividing module and a first path of signals output by the seventh power dividing module; the second 90-degree bridge receives a second path of signals output by the sixth power dividing module and a second path of signals output by the seventh power dividing module;
and the power detector receives the interference signals of the outputs of the first 90-degree bridge and the second 90-degree bridge, and the signals in the power detector change along with a sine function or a cosine function, and the change corresponds to the microwave frequency information of the detected microwave signals.
Further, the fourth wavelength of the detected microwave signal is different between two paths of signals output by the sixth power dividing module, which comprises the following steps:
the sixth power dividing module is a microwave power divider or a 3dB coupler, and the coaxial cable of the second path of signals output by the sixth power dividing module is longer than the first path of signals output by the sixth power dividing module by one quarter wavelength of the detected microwave signals.
Further, the fourth wavelength of the detected microwave signal is different between two paths of signals output by the sixth power dividing module, which comprises the following steps:
the sixth power dividing module is a 90-degree bridge, and the difference between two paths of signals output by the 90-degree bridge is one quarter wavelength of a detected microwave signal.
Based on the same inventive concept, the method for monitoring the microwave frequency variation comprises the following steps:
receiving the detected microwave signal by utilizing a fifth power dividing module, and dividing the detected microwave signal into two paths; one path is used as a first input signal with long delay, and the other path is used as a second input signal with short delay;
the first input signal is introduced into the delay unbalance delta L through the coaxial cable and then is connected into the sixth power dividing module; the phase difference between the two paths of signals output by the sixth power dividing module is one quarter wavelength of the detected microwave signal;
the second input signal is connected to a seventh power dividing module, and the second input signal is divided into two paths;
receiving a first path of signals output by a sixth power dividing module and a first path of signals output by a seventh power dividing module by using a first 90-degree bridge; receiving a second path of signals output by the sixth power dividing module and a second path of signals output by the seventh power dividing module by using a second 90-degree bridge;
and receiving the interference signals of the outputs of the first 90-degree bridge and the second 90-degree bridge by using a power detector, wherein the signals in the power detector change along with a sine function or a cosine function, and the change corresponds to the microwave frequency change information of the detected microwave signals.
Based on the same inventive concept, the device for monitoring absolute microwave frequency according to the present invention is characterized by comprising:
the eighth power dividing module is used for receiving the detected microwave signal and dividing the detected microwave signal into two paths;
the microwave frequency monitoring device is used for receiving a first path of microwave signal from the eighth power division module, and corresponds to the microwave frequency information of the detected microwave signal through the change of the signal in the power detector along with a sine function or a cosine function; the microwave frequency monitoring device is a structure of any device for monitoring the change of the microwave frequency;
the third microwave interferometer comprises a ninth power division module, a second power division module and a third power division module, wherein the ninth power division module is used for receiving a second path of microwave signals from the eighth power division module and dividing the second path of microwave signals into two paths, and output signals of the two paths have small delay unbalance delta L ', delta L' < delta L; the power detector receives the output signals of the two paths, and the signal in the power detector changes along with a sine function or a cosine function and corresponds to the microwave frequency information of the detected microwave signal;
based on the same inventive concept, the method for monitoring absolute microwave frequency according to the present invention is characterized by comprising the following steps:
receiving the detected microwave signal by utilizing an eighth power dividing module, and dividing the detected microwave signal into two paths;
receiving a first path of microwave signal from an eighth power division module by utilizing a microwave frequency monitoring device, and corresponding to first microwave frequency information of the detected microwave signal through the change of a signal in a power detector along with a sine function or a cosine function; the microwave frequency monitoring device is a structure of any device for monitoring the change of the microwave frequency;
in the first microwave frequency information, the frequency variation range of the detected microwave signal is within a monotonic variation interval of a cosine function;
a ninth power dividing module in the third microwave interferometer is utilized to receive a second path of microwave signals from the eighth power dividing module and divide the second path of microwave signals into two paths, and the two paths of output signals are set to be unbalanced delta L ', delta L' < delta L; receiving the output signals of the two paths through a power detector, wherein the signal in the power detector changes along with a sine function or a cosine function and corresponds to second microwave frequency information of the detected microwave signal;
in the second microwave frequency information, the frequency variation range of the detected microwave signal is in a plurality of periods of a cosine function;
and obtaining the absolute frequency of the detected microwave signal through the first microwave frequency information and the second microwave frequency information.
The beneficial effects are that: compared with the prior art, the invention has the advantages that: (1) The invention divides the detected microwave signal into two paths, each path is connected to the radio frequency interferometer module, the delay unbalance of the first microwave interferometer is longer than the delay unbalance of the second microwave interferometer by one quarter wavelength, thereby generating additional phase difference between the two arms; the microwave power detector measures the output of the microwave interferometer to generate two interference signals with opposite phases, the difference value of the two complementary interference signals of the first microwave interferometer is a sine function of the microwave frequency, the difference value of the two complementary interference signals of the second microwave interferometer is in direct proportion to the cosine function of the microwave frequency, and then the variation quantity and the variation process of the microwave frequency can be obtained by utilizing a demodulation algorithm; (2) A third microwave interferometer with a smaller delay imbalance is used to produce a slower output change when changing the microwave frequency, the three microwave interferometers in combination determining the absolute microwave frequency; (3) The invention realizes that the delay unbalance of the first microwave interferometer is longer than the delay unbalance of the second microwave interferometer by one quarter wavelength by utilizing the 90-degree bridge, and can ensure that each frequency point has better 90-degree phase shift compared with the delay line with different lengths or the phase shifter.
Drawings
Fig. 1a is a schematic diagram of an apparatus for monitoring a change in microwave frequency according to embodiment 1 of the present invention.
Fig. 1b shows the ideal test results obtained by four detectors in sequence in the range of 8 to 10GHz of the microwave signal in the device for monitoring microwave frequency variation according to embodiment 1 of the present invention.
Fig. 2 is a schematic diagram of an apparatus for monitoring a change in microwave frequency according to embodiment 2 of the present invention.
Fig. 3 is a schematic diagram of an apparatus for monitoring a change in microwave frequency according to embodiment 3 of the present invention.
Fig. 4 is a schematic diagram of an apparatus for monitoring a change in microwave frequency according to embodiment 4 of the present invention.
Fig. 5a is a schematic diagram of an apparatus for monitoring microwave frequency variation according to embodiment 5 of the present invention.
FIG. 5b is a graph showing the experimental results of the variation of the microwave frequency in the frequency range of 8 to 12GHz with a frequency variation interval of 5MHz, which is measured by the apparatus for monitoring the variation of the microwave frequency according to example 5 of the present invention.
FIG. 5c is a graph showing the experimental results of the variation of the microwave frequency in the frequency range of 8 to 12GHz with a frequency variation interval of 2MHz, which is measured by the apparatus for monitoring the variation of the microwave frequency according to example 5 of the present invention.
FIG. 5d is a graph showing the experimental result of the frequency variation of the microwave with a frequency variation interval of 40KHz measured by the apparatus for monitoring the frequency variation of the microwave according to the embodiment 5 of the present invention.
FIG. 5e is a graph showing the experimental result of the frequency variation of the microwave with a frequency variation interval of 15KHz measured by the apparatus for monitoring the frequency variation of the microwave according to the embodiment 5 of the present invention.
Fig. 6a is a schematic diagram of an apparatus for monitoring absolute microwave frequency in accordance with the present invention.
Fig. 6b is a schematic diagram of the frequency detection result using the apparatus for monitoring absolute microwave frequency in fig. 6 a.
Detailed Description
The technical scheme of the invention is further described below with reference to the accompanying drawings.
Fig. 1a is a schematic structural diagram of an embodiment 1 of the device for monitoring microwave frequency variation according to the present invention. 101. 102, 103 are dual output power splitters or 3dB couplers. 104 and 106 are coaxial cables, the coaxial cable 106 is longer than 104 by a quarter wavelength of the measured frequency, or 106 and 104 are equal in length and then the delay imbalance of the quarter wavelength is achieved by adjusting the microwave phase shifters 105 and 107, and any one of the phase shifters 105 and 107 can be optionally used for achieving the adjustment of the delay imbalance. 108 and 109 are 90 degree bridges. 110. 111, 112, 113 are microwave power detectors. The delay imbalance Δl between the two interferometric arms of the first microwave interferometer 114, whose first microwave interferometer output signal is:
wherein V is 10 And V 20 Is the amplitude of the measured microwave signal, which is proportional to the received microwave power, the responsivity of the detector and the parasitic loss of the microwave interferometer,is the initial phase of the microwave signal. The free spectral range FSR of a microwave interferometer is defined as:
FSR＝1/τ＝c/ΔL (3)
where τ and Δl are the time delay difference created by the two arms of the second microwave interferometer 115 and the actual distance difference of the microwave signal transmitted at the two arms, respectively.
The formula (1) minus the formula (2) is given as:
delay imbalance Δl±λ between the two interference arms of the second microwave interferometer 115 0 4, lambda of 0 Is the wavelength of the microwave signal to be measured. The size is + -lambda 0 The additional delay imbalance of/4 produces a phase of + -pi/2, so the second microwave interferometer output signal is:
wherein V is 30 And V 40 Is the amplitude of the measured microwave signal, which is proportional to the received microwave power, the responsivity of the detector and the parasitic loss of the microwave interferometer,is the initial phase of the microwave signal. The joint equations (4) and (7) can be obtained:
θ＝2πfτ (10)
by using a sine/cosine interpolation algorithm, the change direction and the change size of theta can be obtained, and when the change amount of theta exceeds the integral multiple of 2 pi, the theta can be obtained by the following formula:
the change in frequency can be readily obtained by equation (10):
note that higher resolution of frequency variation can be achieved with a wide range of frequency measurements with a sine-cosine frequency detector. If only one sine or cosine function is used to test the frequency variation, the test range and resolution are limited, and the frequency resolution of the frequency variation is usually tested using only one sine or cosine function as follows:
(13) The equation shows that the frequency resolution of a single sine or cosine function test frequency variation depends on the magnitude of the delay imbalance, which corresponds to a cable length of at least 15km if a frequency resolution of 10kHz is to be achieved.
However, if a sine and cosine frequency detector is used, assuming a 16-bit digital resolution of the acquisition card used to process the data, the length of the delay imbalance would only need to be 0.23m on-axis if a frequency resolution of 10kHz is to be achievedAnd (3) a cable. The above estimation is performed by narrowing the FSR in equation (10) by 2 16 Is multiplied by 2, which is obtainable in half sine or cosine cycles of the test result 16 Data points. Higher frequency resolution can be achieved by adding a larger delay imbalance, since the test technique can unwrap phases exceeding 2pi.
In fig. 1a, a 90 degree phase shift of 115 to 114 is achieved by a delay line or phase shifter, which can only maintain 90 degrees at a specific frequency point, and if frequency changes of different frequency bands are to be tested, different delay amounts need to be replaced, so the structure shown in fig. 1 is complicated in the operation process. Thus, a 90 degree bridge is employed in the configuration shown in fig. 2 to avoid this problem.
Fig. 1b shows the output results of four detectors in the ideal state according to the present invention, corresponding to equations (1), (2), (5) and (6), respectively. Wherein the extent of adjacent peaks and valleys of each curve corresponds to one FSR.
Fig. 2 is a schematic structural view of an embodiment 2 of the device for monitoring microwave frequency variation according to the present invention. The difference from fig. 1a in this structure is that the power divider (or 3dB coupler) 103 is replaced by a 90 degree bridge 203, and the two signals output by the 90 degree bridge can implement pi/2 delay imbalance in a larger frequency range, so that the measurement of the microwave frequency variation can be implemented by ensuring that the microwave interferometers 214 and 215 have the same delay imbalance in the subsequent operation process. The method is essentially different from the sine and cosine optical frequency measurement technology of light, 90-degree phase shift is finished by using a delay line on the light, the applicable delay line can only keep 90-degree phase shift at a certain specific frequency, and larger phase deviation can occur at other frequencies, and the deviation directly causes larger systematic error of a test result, and in the microwave, the microwave has better 90-degree phase shift at each frequency point in the working frequency range. In addition, the high accuracy of the length of the delay imbalance can be achieved by adjusting the microwave phase shifters 205 and 207. The structures 201, 202 are power splitters or 3dB couplers. 203. 208, 209 are 90 degree bridges. 204 and 206 are coaxial cables of equal length. 205. 207 is a microwave phase shifter. 210. 211, 212, 213 are microwave power detectors, 214 and 215 are first and second microwave interferometers.
Although the problem of inconsistent 90-degree phase shift at each frequency point is avoided in the structure, the long delay delta L of the structure needs two parts, so that the test system has a higher cost and a more complex structure, and the 90-degree phase shift of the test system is also changed due to the change of the environmental temperature when the two-section delay quantity is subjected to the operation process.
Fig. 3 is a schematic structural view of embodiment 3 of the device for monitoring microwave frequency variation of the present invention. This structure differs from that of fig. 1a in that the power splitters 101, 102, 103 are replaced by a quarter-divided microwave power splitter 301, the rest of the structure being identical to that of fig. 1 a. 301 in this configuration is a power divider or 3dB coupler. 302 and 303 are coaxial cables and the delay imbalance of the two cables is lambda 0 /4. 304. 305 are microwave phase shifters. 306. 307 is a 90 degree bridge. 308. 309, 310, 311 are microwave power detectors, 312 and 313 are first and second microwave interferometers. This structure is a simplified version of the structure of fig. 1.
Fig. 4 is a schematic structural view of an embodiment 4 of the apparatus for monitoring a change in microwave frequency according to the present invention. The two microwave interferometers in this configuration share a single path of delay balanced coaxial cable 402. Coaxial cable 409 is longer by lambda than 406, 407, 410 0 And/4 is used to achieve a delay imbalance of pi/2. To achieve a high equal length match for the four sections, two microwave phase shifters 408, 411 are inserted in both 407 and 410 for precise adjustment of the four-way delay length. 401, 404, 405 in this configuration are power splitters or 3dB couplers. 402. 403, 406, 407, 409, 410 are coaxial cables. 412 and 413 are 90 degree bridges. 408. 411 is a microwave phase shifter. 414. 415, 416, 417 are microwave power detectors.
Although this structure shares a long delay line Δl, the delay line is still used when 90-degree phase shift of the second microwave interferometer is achieved, and thus the problem of the structure shown in fig. 1 also exists.
Fig. 5a is a schematic structural view of an embodiment 5 of the device for monitoring microwave frequency variation according to the present invention. In this configuration, two microwave interferometers share a single delay balanced coaxial cable 502. The 90 degree bridge 504 is used to achieve a delay imbalance of pi/2 for the two microwave interferometers. In order to achieve better phase matching, the four parts 506, 508, 509, 511 are required to have the same delay amount in the structure, and in order to achieve higher equal-length matching of the four parts, two microwave phase shifters 507, 510 are inserted into the two paths 508 and 511 for accurately adjusting the four-path delay length. 501, 505 in this configuration are power splitters or 3dB couplers. 502. 503, 506, 508, 509, 511 are coaxial cables. 512 and 513 are 90 degree bridges. 507. 510 is a microwave phase shifter. 514. 515, 516, 517 are microwave power detectors. The method is essentially different from the sine and cosine optical frequency measurement technology of light, 90-degree phase shift is finished by using a delay line on the light, the applicable delay line can only keep 90-degree phase shift at a certain specific frequency, and larger phase deviation can occur at other frequencies, and the deviation directly causes larger systematic error of a test result, and in the microwave, the microwave has better 90-degree phase shift at each frequency point in the working frequency range. Furthermore, a power detector is adopted in the structure to extract the information of the microwave frequency variation, and the information is not a photoelectric detector.
The structure perfectly avoids the problems of using a plurality of sections of delay lines and 90-degree phase shift, and greatly improves data processing and experimental operation in the subsequent frequency measurement process. The graphs of the experimental results of the frequency variation interval of 5MHz and 2MHz respectively in the 8 to 12GHz frequency range measured by the structure of FIG. 5a are shown in FIGS. 5b-5 c. Figures 5d-5e show the ability to distinguish between 40KHz and 15KHz frequency variations using the structure of figure 5.
Fig. 6a is a schematic diagram of an apparatus for monitoring absolute microwave frequency according to the present invention, which combines a smaller FSR sine-cosine microwave frequency measurement system 602 with a microwave interferometer 603 having a larger FSR to achieve high resolution absolute microwave frequency measurement. Reference numeral 602 denotes any one of examples 1 to 5 of the apparatus for monitoring a change in microwave frequency according to the present invention, and is the structure of example 5. 603 is another microwave interferometer with a delay imbalance much smaller than deltal. 601, 604 in this configuration are power splitters or 3dB couplers. 605. 606 is a coaxial cable. 607 is a 90 degree bridge. 608. 609 is a microwave power detector.
Fig. 6b illustrates the use of the combination of the larger FSR microwave frequency detector and the smaller FSR microwave frequency detector described in fig. 6a to achieve absolute frequency detection. When the delay unbalance of the large FSR microwave interferometer is set, the frequency variation range of the detected microwave signal needs to be considered to be limited in a monotonic variation interval of the cosine function for measuring the rough absolute microwave frequency. As shown in fig. 6b, a small FSR microwave probe will produce many cycles during this monotonic period. As long as the resolution of the larger FSR is ensured to be good enough, it can be distinguished how large a period of the smaller FSR is, so that the absolute frequency of the microwave signal can be accurately obtained. For example, in some embodiments, a large FSR may be set to tens of GHz, while a small FSR may be set to tens of KHz.
Claims (13)
1. An apparatus for monitoring a change in microwave frequency, comprising:
the first power dividing module is used for receiving the detected microwave signal and dividing the detected microwave signal into two paths;
the second power dividing module is used for receiving a first path of microwave signals from the first power dividing module and dividing the first path of microwave signals into two paths which enter two arms of the first microwave interferometer;
the third power dividing module is used for receiving a second path of microwave signals from the first power dividing module and dividing the second path of microwave signals into two paths which enter two arms of the second microwave interferometer;
the two arms of the first microwave interferometer and the second microwave interferometer are provided with delay unbalance, and the delay unbalance of the second microwave interferometer is longer than that of the first microwave interferometer by a quarter wavelength of a detected microwave signal;
the power detector receives interference signals output by the first microwave interferometer and the second microwave interferometer, and the signals in the power detector change along with a sine function or a cosine function, and the change corresponds to frequency change information of the detected microwave signals.
2. The apparatus for monitoring microwave frequency variation according to claim 1, wherein the first, second and third power dividing modules are each a microwave power divider or a 3dB coupler;
the two arms of the first microwave interferometer and the second microwave interferometer are formed by coaxial cables with different lengths, so that the delay is unbalanced, and the coaxial cable of the second microwave interferometer is longer than the coaxial cable of the first microwave interferometer by a quarter wavelength of a detected microwave signal;
alternatively, the coaxial cable of the second microwave interferometer is equal in length to the coaxial cable of the first microwave interferometer, and either arm of the first microwave interferometer and the second microwave interferometer is coupled to a phase modulator for causing the delay imbalance of the second microwave interferometer to be one-quarter wavelength longer than the delay imbalance of the first microwave interferometer.
3. The apparatus for monitoring microwave frequency variation according to claim 1, wherein the first power dividing module is a microwave power divider or a 3dB coupler, any one of the second power dividing module or the third power dividing module is a 90 degree bridge, and the other is a microwave power divider or a 3dB coupler;
the phase difference between two paths of signals output by the 90-degree bridge is one quarter wavelength of a detected microwave signal;
the two arms of the first microwave interferometer and the second microwave interferometer are formed by coaxial cables with the same length to form delay unbalance.
4. The apparatus for monitoring microwave frequency variations according to claim 1, wherein the first microwave interferometer and the second microwave interferometer each receive and combine microwave signals of two arms using a 90 degree bridge to produce two output interference signals.
5. A method of monitoring a change in microwave frequency, comprising the steps of:
receiving a detected microwave signal by using a first power dividing module, and dividing the detected microwave signal into two paths;
the second power dividing module is utilized to receive a first path of microwave signals from the first power dividing module, and the first path of microwave signals are divided into two paths to enter two arms of the first microwave interferometer;
receiving a second path of microwave signals from the first power dividing module by utilizing the third power dividing module, and dividing the second path of microwave signals into two paths which enter two arms of a second microwave interferometer;
both arms of the first and second microwave interferometers have a delay imbalance Δl, and the delay imbalance of the second microwave interferometer is one quarter wavelength longer than the long sounding microwave signal of the first microwave interferometer;
and receiving interference signals output by the first microwave interferometer and the second microwave interferometer by using a power detector, wherein the signals in the power detector change along with a sine function or a cosine function, and the change corresponds to the microwave frequency change information of the detected microwave signals.
6. An apparatus for monitoring a change in microwave frequency, comprising:
the fourth power dividing module is used for receiving the detected microwave signals and dividing the detected microwave signals into four paths, wherein two paths enter two arms of the first microwave interferometer, and the other two paths enter two arms of the second microwave interferometer;
both arms of the first microwave interferometer and the second microwave interferometer have a delay imbalance, and the delay imbalance of the second microwave interferometer is one-quarter wavelength of the long sounding microwave signal of the first microwave interferometer;
the power detector receives interference signals output by the first microwave interferometer and the second microwave interferometer, and the signals in the power detector change along with a sine function or a cosine function, and the change corresponds to the microwave frequency change information of the detected microwave signals.
7. A method of monitoring a change in microwave frequency, comprising the steps of:
the fourth power dividing module is used for receiving the detected microwave signals and dividing the detected microwave signals into four paths, wherein two paths enter two arms of the first microwave interferometer, and the other two paths enter two arms of the second microwave interferometer;
the two arms of the first microwave interferometer and the second microwave interferometer are provided with delay unbalance, and the delay unbalance of the second microwave interferometer is longer than that of the first microwave interferometer by a quarter wavelength of a detected microwave signal;
and receiving interference signals output by the first microwave interferometer and the second microwave interferometer by using a power detector, wherein the signals in the power detector change along with a sine function or a cosine function, and the change corresponds to the microwave frequency change information of the detected microwave signals.
8. An apparatus for monitoring a change in microwave frequency, comprising:
the fifth power dividing module is used for receiving the detected microwave signals and dividing the detected microwave signals into two paths; one path is used as a first input signal with long delay, and the other path is used as a second input signal with short delay;
the first input signal is introduced into the delay unbalance delta L through the coaxial cable and then is connected into the sixth power dividing module; the phase difference between the two paths of signals output by the sixth power dividing module is one quarter wavelength of the detected microwave signal;
the second input signal is connected to a seventh power dividing module, and the second input signal is divided into two paths;
the first 90-degree bridge receives a first path of signals output by the sixth power dividing module and a first path of signals output by the seventh power dividing module; the second 90-degree bridge receives a second path of signals output by the sixth power dividing module and a second path of signals output by the seventh power dividing module;
and the power detector receives the interference signals of the outputs of the first 90-degree bridge and the second 90-degree bridge, and the signals in the power detector change along with a sine function or a cosine function, and the change corresponds to the microwave frequency change information of the detected microwave signals.
9. The apparatus for monitoring microwave frequency variation according to claim 8, wherein the phase difference between the two signals outputted from the sixth power dividing module comprises:
the sixth power dividing module is a microwave power divider or a 3dB coupler, and the coaxial cable of the second path of signals output by the sixth power dividing module is longer than the first path of signals output by the sixth power dividing module by one quarter wavelength of the detected microwave signals.
10. The apparatus for monitoring microwave frequency variation according to claim 8, wherein the phase difference between the two signals outputted from the sixth power dividing module comprises:
the sixth power dividing module is a 90-degree bridge, and the difference between two paths of signals output by the 90-degree bridge is one quarter wavelength of a detected microwave signal.
11. A method of monitoring a change in microwave frequency, comprising the steps of:
receiving the detected microwave signal by utilizing a fifth power dividing module, and dividing the detected microwave signal into two paths; one path is used as a first input signal with long delay, and the other path is used as a second input signal with short delay;
the first input signal is introduced into the delay unbalance delta L through the coaxial cable and then is connected into the sixth power dividing module; the phase difference between the two paths of signals output by the sixth power dividing module is one quarter wavelength of the detected microwave signal;
the second input signal is connected to a seventh power dividing module, and the second input signal is divided into two paths;
receiving a first path of signals output by a sixth power dividing module and a first path of signals output by a seventh power dividing module by using a first 90-degree bridge; receiving a second path of signals output by the sixth power dividing module and a second path of signals output by the seventh power dividing module by using a second 90-degree bridge;
and receiving the interference signals of the outputs of the first 90-degree bridge and the second 90-degree bridge by using a power detector, wherein the signals in the power detector change along with a sine function or a cosine function, and the change corresponds to the microwave frequency change information of the detected microwave signals.
12. An apparatus for monitoring absolute microwave frequencies, comprising:
the eighth power dividing module is used for receiving the detected microwave signal and dividing the detected microwave signal into two paths;
the microwave frequency monitoring device is used for receiving a first path of microwave signal from the eighth power division module, and corresponds to the microwave frequency information of the detected microwave signal through the change of the signal in the power detector along with a sine function or a cosine function; the structure of any one of claims 1 to 4, 6, 8 to 10;
the third microwave interferometer comprises a ninth power division module, a second power division module and a third power division module, wherein the ninth power division module is used for receiving a second path of microwave signals from the eighth power division module and dividing the second path of microwave signals into two paths, and output signals of the two paths have small delay unbalance delta L ', delta L' < delta L; the power detector receives the output signals of the two paths, and the signal in the power detector changes along with the sine function or the cosine function and corresponds to the microwave frequency information of the detected microwave signal.
13. A method of monitoring absolute microwave frequencies, comprising the steps of:
receiving the detected microwave signal by utilizing an eighth power dividing module, and dividing the detected microwave signal into two paths;
receiving a first path of microwave signal from an eighth power division module by utilizing a microwave frequency monitoring device, and corresponding to first microwave frequency information of the detected microwave signal through the change of a signal in a power detector along with a sine function or a cosine function; the structure of any one of claims 1 to 4, 6, 8 to 10;
in the first microwave frequency information, the frequency variation range of the detected microwave signal is within a monotonic variation interval of a cosine function;
a ninth power dividing module in the third microwave interferometer is utilized to receive a second path of microwave signals from the eighth power dividing module and divide the second path of microwave signals into two paths, and the two paths of output signals are set to be unbalanced delta L ', delta L' < delta L; receiving the output signals of the two paths through a power detector, wherein the signal in the power detector changes along with a sine function or a cosine function and corresponds to second microwave frequency information of the detected microwave signal;
in the second microwave frequency information, the frequency variation range of the detected microwave signal is in a plurality of periods of a cosine function;
and obtaining the absolute frequency of the detected microwave signal through the first microwave frequency information and the second microwave frequency information.
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