CN213960073U - Light intensity modulation radio frequency signal phase consistency measuring device - Google Patents
Light intensity modulation radio frequency signal phase consistency measuring device Download PDFInfo
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- CN213960073U CN213960073U CN202022782902.9U CN202022782902U CN213960073U CN 213960073 U CN213960073 U CN 213960073U CN 202022782902 U CN202022782902 U CN 202022782902U CN 213960073 U CN213960073 U CN 213960073U
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Abstract
The utility model discloses a light intensity modulation radio frequency signal phase uniformity measuring device, including setting up test signal generation module, a n optical divider, photoswitch, quilt photometry electricity receiving module, reference photoelectricity receiving module, move looks ware, phase measurement module and control calculation module at the central station to and set up a n light passback sending module at a n transmitting station. The utility model provides a transmitting station and transmitting station distance far away and inconvenient phase uniformity problem of measuring between each transmitting station in the measurement link of radio frequency phase finding system, have easily to realize, characteristics with low costs and efficient.
Description
Technical Field
The utility model relates to an optical fiber communication technical field, concretely relates to luminous intensity modulation radio frequency signal phase uniformity measuring device.
Background
With the development of modern optical fiber communication technology, the optical fiber communication technology has been increasingly applied to the field of radio frequency signal optical fiber transmission. Most radio frequency signal transmission systems at present have no requirement on phase consistency technical indexes, but in application occasions such as radio frequency phase measurement systems, the accuracy of measurement indexes such as target distance, direction and the like is high, the system has strict requirements on phase consistency indexes of transmitted and received multi-channel detection (radio frequency) signals, and the performance indexes of the system can be ensured only when the phase consistency indexes are required to be controlled within a specified range.
Due to the effects of temperature variations, maintenance, component aging, and the like, the transmission delay of optical transmission equipment, cables, and optical fibers can change. The change coefficient of the commonly used G.652 single-mode optical fiber is about 30-60 ps/km.C. In engineering application, in order to ensure the reliable operation of the system, the optical cable between the transmitting station and the central station ensures the basic consistency of the temperature and the temperature drift of the optical cable in a buried mode. However, even if the temperature and the temperature drift of the optical cable are substantially the same, the phases of the respective transmission channels of the radio frequency signals of the central station and the transmitting station still change to different degrees in long-term operation, so that the operation performance of the phase measurement system is reduced. Therefore, in order to ensure the system performance, the phase difference of the radio frequency signals from the central station to each transmitting station needs to be measured, and then phase adjustment and compensation are performed to ensure the system working performance.
In the traditional radio frequency phase measurement system, because each transmitting station is not far away from a central machine room, and radio frequency signals are transmitted between the transmitting stations and the central machine room by cables, when measuring the phase, the phase of the radio frequency signals of each station can be directly measured by using a vector network analyzer only by connecting the signals of the transmitting stations to the vector network analyzer of the central station by using the radio frequency cables, and the phase difference of each radio frequency signal is calculated according to the phase difference to measure the consistency of the phase of the system. However, as the requirements for measuring distance and azimuth resolution are improved, the existing radio frequency phase measurement system needs to adopt a large-range layout, and at the moment, the central station and the transmitting station are distributed in a large geographical position. At this time, the conventional method of directly connecting the transmitting station signal to the vector network analyzer of the central station by using the radio frequency cable to realize the phase measurement of the radio frequency signal of each station is no longer applicable.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve is that current radio frequency based on optic fibre surveys looks system's phase uniformity measuring problem, provides a light intensity modulation radio frequency signal phase uniformity measuring device.
In order to solve the above problems, the utility model discloses a realize through following technical scheme:
the device for measuring the phase consistency of the light intensity modulation radio frequency signal comprises a test signal generation module, n light return transmission modules, n optical dividers, an optical switch, a measured photoelectric receiving module, a reference photoelectric receiving module, a phase shifter, a phase measurement module and a control calculation module; wherein the optical switch has n input terminals and 1 output terminal; the n paths of outputs of the test signal generating module are connected with the input ends of n optical transmitters of a central station of the radio frequency phase measurement system; the output ends of n optical transmitters of the central station of the radio frequency phase measurement system are respectively connected with the input ends of n optical transmitting stations of the radio frequency phase measurement system; the electrical signal input ends of the n optical return transmitting modules are respectively connected with the output ends of n optical transmitting stations of the radio frequency phase measurement system; the optical signal output ends of the n optical return transmission modules are respectively connected with the input ends of the n optical splitters through optical cables; one of the 1 optical splitter of the n optical splitters, namely the 2 output ends of the reference optical splitter, is connected with the input end of the reference photoelectric receiving module, and the other output end of the reference photoelectric receiving module is connected with one input end of the optical switch; the other n-1 optical splitters of the n optical splitters are 2 paths of output ends of the tested optical splitter, one path is suspended, and the other path is connected with one input end of the optical switch; the output end of the optical switch is connected with the input end of the detected photoelectric receiving module; the output end of the reference photoelectric receiving module is directly connected with one input end of the phase measurement module, and the output end of the measured photoelectric receiving module is connected with the other input end of the phase measurement module through the phase shifter; the output end of the phase measurement module is connected with the input end P2 of the control calculation module, one control end P1 of the control calculation module is connected with the control end of the optical switch, and the other control end P0 of the control calculation module is connected with the control end of the test signal generation module; and n is the number of the light emitting stations of the radio frequency phase measurement system.
In the scheme, a test signal generation module, n optical splitters, an optical switch, a measured photoelectric receiving module, a reference photoelectric receiving module, a phase shifter, a phase measurement module and a control calculation module are arranged at a central station of a radio frequency phase measurement system; the n optical return transmission modules are respectively arranged at n optical transmitting stations of the radio frequency phase measurement system.
In the scheme, the control calculation module is also connected with a computer arranged at the central station.
In the above scheme, the optical signal output ends of the n optical backhaul sending modules are connected with the input ends of the n optical splitters through n-core optical cables.
In the above scheme, the splitting ratios of the n optical splitters are the same.
Compared with the prior art, the utility model has the characteristics of as follows:
1. the problem that the phase consistency among all transmitting stations is inconvenient to measure because the transmitting stations in a measuring link are far away from the transmitting stations is solved;
2. the problem that a common vector analyzer can only measure the phase of an electric signal of a limited channel (usually 2-4 channels) is solved;
3. the problem of multi-channel signal phase consistency measurement cycle time is solved, and the 16-channel measurement time is not more than 5 minutes;
4. each component of the measuring circuit adopts the existing component, and is easy to realize;
5. the cost is low, the measuring circuit is provided with a test signal generating module and a phase measuring module, and 2 expensive instruments such as the test signal generating module and a vector network analyzer are not needed;
6. the measuring method is simple and easy to implement, and is convenient to popularize and apply.
Drawings
Fig. 1 is a schematic block diagram of a light intensity modulation rf signal phase consistency measuring apparatus.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the following specific examples.
A device for measuring phase consistency of light intensity modulation radio frequency signals is shown in figure 1 and comprises a test signal generation module, n light return transmission modules, n light splitters, a light switch, a measured photoelectric receiving module, a reference photoelectric receiving module, a phase shifter, a phase measurement module and a control calculation module. In the utility model, a test signal generation module, n optical splitters, an optical switch, a measured photoelectric receiving module, a reference photoelectric receiving module, a phase shifter, a phase measurement module and a control calculation module are arranged at a central station of a radio frequency phase measurement system; the n optical return transmission modules are respectively arranged at n optical transmitting stations of the radio frequency phase measurement system. n is the number of light emitting stations of the radio frequency phase measurement system, and in the embodiment, n is 16.
The n-path output of the test signal generation module is connected with the input ends of n optical transmitters of the central station of the radio frequency phase measurement system. The output ends of the n optical transmitters of the central station of the radio frequency phase measurement system are respectively connected with the input ends of the n optical transmitting stations of the radio frequency phase measurement system. The electrical signal input ends of the n optical return transmitting modules are respectively connected with the output ends of the n optical transmitting stations of the radio frequency phase measurement system. And the optical signal output ends of the n optical return transmission modules are respectively connected with the input ends of the n optical splitters through optical cables. And 1 of the n optical splitters, namely 2 output ends of the reference optical splitter, one output end is connected with the input end of the reference photoelectric receiving module, and the other output end is connected with one input end of the optical switch. The other n-1 optical splitters of the n optical splitters are 2 output ends of the tested optical splitter, one output end is suspended, and the other output end is connected with one input end of the optical switch. The output end of the optical switch is connected with the input end of the detected photoelectric receiving module. The output end of the reference photoelectric receiving module is directly connected with one input end of the phase measurement module, and the output end of the measured photoelectric receiving module is connected with the other input end of the phase measurement module through the phase shifter. The output end of the phase measurement module is connected with the input end P2 of the control calculation module, one control end P1 of the control calculation module is connected with the control end of the optical switch, and the other control end P0 of the control calculation module is connected with the control end of the test signal generation module.
The working frequency of the test signal generation module is 0.3 MHz-300 MHz, the minimum resolution is 1Hz, the output amplitude is-10 dBm- +10dBm, the output impedance is 50 omega +/-0.1%, the length of a cable connected with the light emission station is 500 +/-10 mm, and the phase consistency is less than or equal to 0.05 DEG @30 MHz. The test signal generation module adopts serial data control, the length of the control data is 8 bytes, the length of each byte is 8 bits, and the output amplitude and the output frequency can be controlled. The data format is: 8-bit synchronization bits, 8-bit amplitude bits, 8-bit giga hundred mega frequency bits, 8-bit deca mega and mega frequency bits, 8-bit hundred k and ten k frequency bits, 8-bit frequency bits of k and hundred Hz, 8-bit frequency bits of ten Hz and Hz, and 8-bit check bits.
The 8bit sync bits are: 11111111.
the 8bit amplitude bits are: the control range was-12.6 dBm- +13.0dBm, see Table 1:
table 18bit frequency bits: the numerical range is 0-99, see table 2:
TABLE 2
The working signal frequency range of the optical transmission and transmission module is 0.1 MHz-300 MHz, the radio frequency input amplitude range is 0 dBm- +10dBm, the 24-hour phase stability is less than or equal to 0.25 degrees @30MHz, the phase consistency of the optical transmission and transmission module is less than or equal to 0.05 degrees @30MHz, the optical wavelength is 1550.12nm of DWDM, the output optical power is +5 +/-0.1 dBm, and the optical fiber interface is FC/APC. In order to keep the temperature and the temperature drift of the optical cable substantially consistent, in this embodiment, the optical signal output ends of the n optical backhaul transmitting modules are connected with the input ends of the n optical splitters through the n-core optical cable.
Each optical return transmission module is connected with the optical switch through an optical splitter, and the splitting ratios of the n optical splitters are the same so as to ensure that the powers of the measured signal and the reference signal sent into the phase measurement module are basically the same. In the present embodiment, each of the 16 optical splitters is 1: 2, single-mode PLC optical splitter, splitting ratio is 50%: 50%, light splitting error less than or equal to +/-5%, insertion loss less than or equal to 3.5dB, input and output optical fiber length 300 +/-5 mm, optical splitter light splitting end delay consistency less than or equal to 1 picosecond (ps), and optical fiber interface FC/APC.
The optical switch is provided with n input ends and 1 output end. In this embodiment, the optical switch is a 16:1 optical switch. 16: the 1 optical switch is a single-mode MEMS optical switch, the insertion loss of the optical switch is not more than 1.5dB, the repeatability is excellent by 1dB, the crosstalk is better than 50dB, the switching time is better than 50ms, the length of an input/output optical fiber is 300 +/-5 mm, the consistency of channel delay is not more than 1 picosecond (ps), and the interface is FC/APC. 16:1, the channel switching of the optical switch is controlled by a control calculation module through a P1 control port, 16:1 optical switch channel switching code as shown in table 3:
TABLE 3
The frequency ranges of the reference photoelectric receiving module and the measured photoelectric receiving module are 0.1 MHz-300 MHz, the optical interface is single-mode light, the range of the light input amplitude is-10 dBm- +5dBm, the radio frequency output amplitude is-40 dBm- +10dBm, the 24-hour phase stability is less than or equal to 0.2 degrees @30MHz, and the optical fiber interface is FC/APC.
The frequency range of the phase shifter is 1 MHz-50 MHz, the range of the radio frequency input amplitude is-42 dBm-8 dBm, the gain is +/-0.2 dB, the phase shift amount is about 60 degrees, the phase of the measured signal is delayed by 62-125 degrees compared with the phase of the reference signal, and the phase shifter conforms to the optimal phase discrimination range of the phase measurement module. The phase shifter adopts an active broadband phase shifter consisting of an operational amplifier, a resistor, a capacitor and an inductor, and the 24-hour phase stability is 0.1 degree.
The frequency range of the phase measurement module is 0.1 MHz-2000 MHz, the amplitude range of input signals is-50 dBm-5 dBm, the phase discrimination range is 0-180 degrees, the phase discrimination precision is 0.1 degrees, the 48h amplitude temperature stability is +/-0.1 degrees, the optimal phase discrimination linear range is 20-160 degrees, the output phase difference data is 16-bit TTL level data, and the phase difference data format is a direct binary code. The phase difference data format is shown in table 4:
TABLE 4
Because the optical cable from the central station to the transmitting station usually adopts a buried mode, the consistency of the environmental temperature of the optical cable and the transmission time delay during the phase consistency measurement is ensured. The phase consistency measurement is to measure the phase consistency of light emission and light reception of the user radio frequency signal transmission channel.
The 16 channels of return radio frequency signals of the 16 transmitting stations are transmitted back to the central station through 16 optical fibers respectively, and return optical signals are input into the 16 optical splitters to carry out 1: 2 optical branch, then input 16:1 optical switch for measurement channel selection. When a phase measurement system is constructed, in order to ensure that the phases of radio-frequency signals transmitted by all transmitting stations are consistent, the lengths of optical fibers from a central station to each transmitting station are strictly and equally laid, and return optical fibers are also strictly and equally long, so that when the phases of the radio-frequency signals of the transmitting stations are the same, 16 return signals are transmitted to 16:1 the phase of the optical switch should be consistent, the transmission optical path of the measured photoelectric receiving module is longer than the optical path length of the reference photoelectric receiving module by 16: the length of the optical fiber input and output by the 1 optical switch is about 2 × 300 ± 5mm ≈ 1200mm, the delay time of the optical fiber is 6ns, the phase delay of the 1 MHz-30 MHz radio frequency signal is 2.16-64.8 degrees, the phase shift of the phase shifter is about 60 degrees, the phase of the measured signal is 62-125 degrees later than that of the reference signal, and the phase detection method accords with the optimal phase detection range of the phase measurement module.
In system application, the optical power of 16 radio frequency optical signals transmitted back to the central station by the transmitting station should be in the range of-10 dBm to +5 dBm. During phase measurement, the first path of radio frequency return signal optical fiber is connected with the common end of the first optical splitter, the second path of radio frequency return signal optical fiber is connected with the common end of the second optical splitter, and so on, and the sixteenth path of radio frequency return signal optical fiber is connected with the common end of the sixteenth optical splitter. The communication end of the control calculation module is connected with a network interface of the computer. The rf return signals are sent to 16:1 input of an optical switch.
The control end of the P1 of the control calculation module sends out a switching command, and the switching command is input into the control module 16:1 optical switch control terminal, 16: the 1 optical switch selects channels according to the command, and outputs optical signals of a selected channel i (i is 1-16) to the photoelectric receiving module to be detected. The tested photoelectric receiving module recovers the input light into an electric signal through photoelectric conversion and outputs the electric signal, then the electric signal is input into the phase shifter to perform phase shift of 60 degrees, and the radio-frequency signal after phase shift is output to the phase measuring module as a tested signal. The 1 light splitting output of the reference light splitter is connected to a reference photoelectric receiving module to carry out photoelectric conversion and recover to an electric signal, then the electric signal is output to a phase measurement module as a reference signal to be compared with the phase of a measured signal, the phase difference between the two signals is converted into a voltage signal, analog-to-digital conversion is carried out by an A/D chip in the module, the conversion bit number is 16 bits, the conversion rate is 2MHz, and A/D conversion data is output to a control calculation module by an output port of the phase measurement module to be stored, calculated and the like.
The control end of the control computing module P1 sends a switch command to 16:1, selecting the channel 1 by the control end of the optical switch. The control end of the control calculation module P0 sends out a control instruction, the control test signal generation module outputs 0dBm amplitude, the test frequency f (in this example, the test frequency f is assumed to be 1MHz at the beginning, 30MHz at the end and 0.1MHz at the interval) is sent out at 30us time interval in turn at 1MHz, 1.1MHz and 1.2MHz … 30MHz, the total number of the test frequency f is 290, and the sending period is 8.7 ms. The phase values P1-1(1MHz), P1-1(1.1MHz) and … P1-1(30MHz) of each frequency point and the reference signal (channel 1) are measured in sequence.
The channels 2 are selected to 16 in sequence at intervals of 50ms, the radio frequency phase difference (P2-1(1MHz), P2-1(1.1MHz), … P2-1(30MHz), … P16-1(1MHz), P16-1(1.1MHz) and … P16-1(30MHz)) of the 16 paths of radio frequency return signals and the reference signals is tested in sequence, and finally the consistency (delta P (1MHz), delta P (1.1MHz) and … delta P (30MHz) of each path of radio frequency return signals is calculated by a control calculation module.
The frequency point of the common measurement of 16 channels is 16 × 290 ═ 4640, the test time is 4640 × 30us ═ 139.2ms, and the work period of 16 channels is 16 × 50ms ═ 750 ms.
The phase consistency delta P calculation method comprises the following steps: Δ P (1MHz) at 1MHz frequency Pi-1(1MHz) max-Pj-1(1MHz) min. 1, 2, … 16.
And sequentially calculating the phase consistence of other frequencies, and reporting the final phase consistence result to an external computer.
The utility model discloses a transmission measurement problem that central station and launching station distance are far away is solved to the optical fiber transmission mode, selects a photoswitch's mode to realize the fast switch-over through the multichannel and measures, sends a series of test frequency f through setting up test signal generation module, and measurement system phase uniformity under various frequencies for surveying looks system performance and mastering and provide detailed data, improves measurement accuracy through the mode that sets up the looks ware.
It should be noted that, although the above-mentioned embodiments of the present invention are illustrative, the present invention is not limited thereto, and therefore, the present invention is not limited to the above-mentioned embodiments. Other embodiments, which can be made by those skilled in the art in light of the teachings of the present invention, are considered to be within the scope of the present invention without departing from the principles thereof.
Claims (5)
1. Light intensity modulation radio frequency signal phase consistency measuring device, characterized by: the device comprises a test signal generation module, n light return transmission modules, n optical splitters, an optical switch, a measured photoelectric receiving module, a reference photoelectric receiving module, a phase shifter, a phase measurement module and a control calculation module; wherein the optical switch has n input terminals and 1 output terminal;
the n paths of outputs of the test signal generating module are connected with the input ends of n optical transmitters of a central station of the radio frequency phase measurement system; the output ends of n optical transmitters of the central station of the radio frequency phase measurement system are respectively connected with the input ends of n optical transmitting stations of the radio frequency phase measurement system; the electrical signal input ends of the n optical return transmitting modules are respectively connected with the output ends of n optical transmitting stations of the radio frequency phase measurement system; the optical signal output ends of the n optical return transmission modules are respectively connected with the input ends of the n optical splitters through optical cables; one of the 1 optical splitter of the n optical splitters, namely the 2 output ends of the reference optical splitter, is connected with the input end of the reference photoelectric receiving module, and the other output end of the reference photoelectric receiving module is connected with one input end of the optical switch; the other n-1 optical splitters of the n optical splitters are 2 paths of output ends of the tested optical splitter, one path is suspended, and the other path is connected with one input end of the optical switch; the output end of the optical switch is connected with the input end of the detected photoelectric receiving module; the output end of the reference photoelectric receiving module is directly connected with one input end of the phase measurement module, and the output end of the measured photoelectric receiving module is connected with the other input end of the phase measurement module through the phase shifter; the output end of the phase measurement module is connected with the input end P2 of the control calculation module, one control end P1 of the control calculation module is connected with the control end of the optical switch, and the other control end P0 of the control calculation module is connected with the control end of the test signal generation module;
and n is the number of the light emitting stations of the radio frequency phase measurement system.
2. The optical intensity modulated radio frequency signal phase consistency measuring device of claim 1, wherein: the test signal generation module, the n optical splitters, the optical switch, the measured photoelectric receiving module, the reference photoelectric receiving module, the phase shifter, the phase measurement module and the control calculation module are arranged at a central station of the radio frequency phase measurement system; the n optical return transmission modules are respectively arranged at n optical transmitting stations of the radio frequency phase measurement system.
3. The optical intensity modulated radio frequency signal phase consistency measuring device of claim 1, wherein: the control calculation module is also connected with a computer arranged at the central station.
4. The optical intensity modulated radio frequency signal phase consistency measuring device of claim 1, wherein: and the optical signal output ends of the n optical return transmission modules are connected with the input ends of the n optical splitters through an n-core optical cable.
5. The optical intensity modulated radio frequency signal phase consistency measuring device of claim 1, wherein: the splitting ratios of the n optical splitters are the same.
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| CN112491466A (en) * | 2020-11-26 | 2021-03-12 | 中国电子科技集团公司第三十四研究所 | Light intensity modulation radio frequency signal phase consistency measuring device and measuring method |
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| CN112491466B (en) * | 2020-11-26 | 2024-05-28 | 中国电子科技集团公司第三十四研究所 | Light intensity modulation radio frequency signal phase consistency measuring device and measuring method |
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