CN111181595B - Second harmonic cancellation method and device and DAS remote machine - Google Patents
Second harmonic cancellation method and device and DAS remote machine Download PDFInfo
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- CN111181595B CN111181595B CN201911417531.XA CN201911417531A CN111181595B CN 111181595 B CN111181595 B CN 111181595B CN 201911417531 A CN201911417531 A CN 201911417531A CN 111181595 B CN111181595 B CN 111181595B
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- H04B1/525—Hybrid arrangements, i.e. arrangements for transition from single-path two-direction transmission to single-direction transmission on each of two paths or vice versa with means for reducing leakage of transmitter signal into the receiver
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Abstract
The invention relates to a second harmonic cancellation method and device for a DAS remote machine and the DAS remote machine, wherein the second harmonic cancellation device comprises: the signal extraction module is used for extracting a second harmonic signal in the first main channel signal; the cancellation module is used for performing signal processing on the second harmonic signal extracted by the signal extraction module and then performing cancellation processing on the second harmonic signal of the first main channel signal to form a second main channel signal; the detection module is used for detecting the cancellation effect of the second main channel signal to obtain a detection result; and the processing module is used for receiving the detection result. The invention carries out cancellation processing on the second harmonic generated by the radio frequency module, so that the second harmonic does not interfere with the uplink of other frequency bands.
Description
Technical Field
The invention relates to the technical field of mobile communication equipment, in particular to a second harmonic cancellation method and device for a DAS (distributed antenna system) remote machine and the DAS remote machine.
Background
With the rapid development of mobile communication, the coverage requirement of mobile communication signals is higher and higher, and the application of high-power DAS is more and more common. The high-power DAS system generally comprises a near-end machine, an expansion unit and a far-end machine. The near-end machine is mainly used for completing the access of all information sources and the convergence function of all the information sources. The expansion unit mainly has the functions of transferring and playing a role in distribution and combination. As shown in fig. 1, which is a schematic block diagram of the principle of the conventional high-power DAS remote device, the remote device mainly functions to separate downlink signals, amplify the power of each downlink signal by a radio frequency module (including a power amplifier), combine the downlink signals by a multi-frequency combiner, and transmit the combined downlink signals through an antenna. Meanwhile, the antenna can receive uplink signals of each frequency band, the uplink signals are filtered and separated by the multi-frequency combiner and then are sent to the radio frequency module for signal amplification, then the uplink signals are sent to the digital module, the digital module completes relevant processing and then is sent to the optical transceiver unit, and the optical transceiver unit transmits the uplink signals to the extension unit through optical fibers. Because a radio frequency module (including a power amplifier) can newly generate a second harmonic signal while amplifying a downlink main signal, for a high-power DAS (40W device), the strength of the second harmonic signal is about-5 dBm to 0dBm, and in order to prevent the second harmonic from being connected in series with an uplink path of other frequency bands to interfere with uplink of other frequency bands, a cavity filter is adopted to suppress the second harmonic in the prior art. The cavity filter in the DAS equipment in the prior art has insertion loss of about 2dB to a main signal, the 2dB insertion loss is made up, the output power of a radio frequency module must be increased by 2dB, the design difficulty and the design cost of the radio frequency module are greatly increased, and meanwhile, the cavity filter in the DAS equipment in the prior art is not only large in size but also high in cost, so that the miniaturization design of products is not facilitated, and the universality of a product platform is also influenced.
Disclosure of Invention
The present invention is directed to overcome at least one of the above-mentioned drawbacks (deficiencies) of the prior art, and provides a second harmonic cancellation apparatus and method for a DAS remote, and a DAS remote, in which the second harmonic generated by a radio frequency module is cancelled, so that the second harmonic does not interfere with uplink in other frequency bands.
The technical scheme adopted by the invention is as follows:
a second harmonic cancellation arrangement for a DAS remote machine, comprising:
the signal extraction module is used for extracting a second harmonic signal in the first main channel signal;
the cancellation module is used for performing signal processing on the second harmonic signal extracted by the signal extraction module and then performing cancellation processing on the second harmonic signal of the first main channel signal to form a second main channel signal;
the detection module is used for detecting the cancellation effect of the second main channel signal to obtain a detection result;
and the processing module is used for receiving the detection result.
The second harmonic signal of the main channel signal is extracted through the signal extraction module, the second harmonic signal extracted is subjected to amplitude modulation and phase modulation and other processing through the cancellation module, the processed second harmonic signal is coupled to the main channel and is offset with the second harmonic signal in the first main channel signal, and the problem that the second harmonic interferes with uplink of other frequency bands is solved; the second main path signal is generated after the second main path signal is processed by the cancellation module. Extracting a second harmonic signal in the second main channel signal through a detection module and carrying out power detection on the second harmonic signal in the second main channel signal to obtain a detection result; the processing module can monitor the detection result.
Further, the processing module is further configured to perform real-time amplitude modulation and/or phase modulation on the second harmonic signal according to the received detection result. The processing module carries out real-time amplitude modulation and/or phase modulation on the second harmonic signal according to the detection result, so that the cancellation processing can be dynamically adjusted in real time, and the cancellation effect of the second harmonic signal is always in an optimal state.
Furthermore, the signal extraction module includes a first coupler and a first filter, a main input end of the first coupler is used for accessing the first main path signal, a coupling output end of the first coupler is connected to an input end of the first filter, an output end of the first filter is connected to an input end of the cancellation module, an output end of the cancellation module is connected to a coupling input end of the first coupler, and a main output end of the first coupler is connected to the detection module.
The first coupler couples the main channel signal and then filters the main channel signal by the first filter, so that a second harmonic signal in the main channel signal is extracted, and the extraction of the second harmonic signal can be finished by adopting the existing coupler and filter, so that the design difficulty and the design cost in the DAS equipment can be reduced.
Furthermore, the signal extraction module further comprises an amplitude limiter, the coupling output end of the first coupler is connected with the input end of the amplitude limiter, and the output end of the amplitude limiter is connected with the input end of the first filter.
The amplitude limiter is adopted to carry out amplitude limiting on the first main channel signal, and a signal with larger power is removed, so that the first coupler and the first filter extract more accurate second harmonic signals, and after amplitude limiting, a circuit device connected subsequently can select a common model with small power.
Furthermore, the cancellation module comprises an amplitude modulator, a phase modulator and a first amplifier, an input end of the amplitude modulator is connected with an output end of the first filter, an output end of the amplitude modulator is connected with an input end of the first amplifier, an output end of the first amplifier is connected with an input end of the phase modulator, and an output end of the phase modulator is connected with a coupling input end of the first coupler.
The principle that two signals with the same frequency and amplitude and the same phase are synthesized to be offset is utilized, an amplitude modulator is used for carrying out amplitude modulation on the second harmonic signal, a first amplifier amplifies the amplitude-modulated second harmonic signal, a phase modulator carries out phase modulation on the amplified second harmonic signal, the phase-modulated second harmonic signal is injected into a first main channel by a first coupler to be synthesized with the first main channel signal, and offset processing of the second harmonic signal is completed, so that the second harmonic signal in the first main channel signal is offset, and uplink of other frequency bands cannot be interfered. When the radio frequency module is applied to DAS equipment, the cancellation processing of second harmonic signals is completed by using an amplitude modulator, an amplifier, a phase modulator and a coupler, so that the design difficulty and the design cost of a radio frequency module of a key component in the DAS equipment and the power consumption of the whole radio frequency module can be obviously reduced.
Further, the detection module comprises a load, a second coupler, a filter circuit, a detector and an analog-to-digital converter; the main input end of the second coupler is connected with the main output end of the first coupler, and the coupling input end of the second coupler is connected with a load;
the input end of the filter circuit is connected with the coupling output end of the second coupler and is used for filtering the coupled second main channel signal and extracting a new second harmonic signal;
the output end of the filter circuit is connected with the input end of the detector;
the output end of the detector is connected with the input end of the analog-to-digital converter and is used for detecting a new second harmonic signal formed by the filter circuit and transmitting a generated detection result to the analog-to-digital converter;
the output end of the analog-to-digital converter is connected with a processing module.
The second coupler couples the second main path signal, the filter circuit filters the coupled second main path signal and extracts a new second harmonic signal, the extracted new second harmonic signal is amplified and then sent to the detector to carry out power detection on the new second harmonic signal, and therefore the good or bad of the cancellation effect can be known.
Further, the filter circuit includes a second filter, an input end of the second filter is connected to the coupling output end of the second coupler, and an output end of the second filter is connected to an input end of the detector, and is configured to filter the coupled new main path signal and extract a new second harmonic signal.
And filtering the second main channel signal through a second filter so as to extract an accurate new second harmonic signal.
Further, the filter circuit further comprises a third filter and at least one second amplifier connected in series between an output of the second filter and an input of the third filter; the output end of the third filter is connected with the input end of the detector, and the output end of the third filter is connected with the input end of the detector.
Through the double filtering and amplification of the filter circuit, the purpose is to extract a more accurate new second harmonic signal.
A second harmonic cancellation method is applied to a DAS remote machine and comprises the following steps:
extracting a second harmonic signal in the first main channel signal;
after the extracted second harmonic signal is subjected to signal processing, the second harmonic signal and a second harmonic signal of the first main channel signal are subjected to cancellation processing to form a second main channel signal;
extracting a second harmonic signal in the second main channel signal, carrying out power detection on the second harmonic signal in the second main channel signal and generating a detection result;
and dynamically adjusting the cancellation processing according to the detection result.
The second harmonic signal of the first main channel signal is extracted and subjected to cancellation processing, so that the second harmonic signal in the first main channel signal is cancelled, and the problem that the second harmonic interferes with the uplink of other frequency bands is solved; the second harmonic signal in the second main channel signal is extracted to detect the cancellation effect, and the cancellation processing is dynamically adjusted in real time according to the detection result, so that the cancellation effect of the second harmonic signal is always in the optimal state.
Further, the cancellation processing is dynamically adjusted according to the detection result, namely, the second harmonic signal in the extracted first main channel signal is subjected to real-time amplitude modulation and/or phase modulation according to the detection result.
And carrying out real-time amplitude modulation or phase modulation on the second harmonic signal in the extracted first main channel signal according to the detection result, and offsetting the second harmonic signal in the extracted first main channel signal with the second harmonic signal in the original main channel signal after processing, so that the cancellation effect of the second harmonic signal is always in an optimal state.
A DAS far-end machine utilizing the second harmonic cancellation device comprises a digital module, a radio frequency module, a multi-frequency combiner and the cancellation device, wherein the digital module is connected with the radio frequency module and used for processing signals; the radio frequency module is connected with the multi-frequency combiner and is used for amplifying signals and power; the cancellation device is connected with the radio frequency module and is used for canceling a second harmonic signal generated in the process that the radio frequency module amplifies signals and power; the multi-frequency combiner is connected with the cancellation device and used for suppressing the second harmonic signals after cancellation.
The cancellation device is adopted to cancel the second harmonic signal generated by the radio frequency module, so that a good cancellation effect can be realized, and the suppression of the rear-stage multi-frequency combiner is added, so that the second harmonic signal generated by the radio frequency module can not interfere the uplink of other frequency bands; moreover, the cancellation device does not cause the attenuation of the main channel signal in the process of canceling the second harmonic signal, so that the design difficulty, the design cost and the whole machine power consumption of a radio frequency module of a key component in DAS equipment can be reduced; in addition, the cancellation device can be integrated into the radio frequency module to realize an integrated design, so that the volume of the DAS equipment is reduced.
Compared with the prior art, the invention has the beneficial effects that:
(1) according to the invention, the second harmonic signal of the first main channel signal is extracted, the second harmonic signal is subjected to amplitude modulation and phase modulation processing and then coupled to the main channel again, and offset processing is formed with the second harmonic signal in the first main channel signal, so that the problem that the second harmonic interferes with the uplink of other frequency bands is solved;
(2) according to the invention, the cancellation processing is dynamically adjusted in real time according to the detection result, so that the cancellation effect of the second harmonic signal is always in an optimal state;
(3) the invention is designed and finished by adopting common components such as a coupler, an amplifier, an amplitude modulator, a phase modulator and the like, and has simple design and realization and low cost.
(4) The cavity filter in the prior art has insertion loss of about 2dB to the main signal, and the cancellation module of the second harmonic cancellation device of the invention basically has no attenuation to the main signal, so the design difficulty and the design cost of a radio frequency circuit (including a power amplifier) which is a key part in DAS equipment, the power consumption of the whole machine and the like can be obviously reduced.
Drawings
Fig. 1 is a schematic block diagram of a conventional high power DAS remote.
Fig. 2 is a schematic block diagram of the inside of a cancellation apparatus according to an embodiment of the present invention.
Fig. 3 is a schematic block diagram of a high power DAS remote according to an embodiment of the invention.
Detailed Description
The drawings are only for purposes of illustration and are not to be construed as limiting the invention. For a better understanding of the following embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
Example 1
In one embodiment, there is provided a second harmonic cancellation arrangement for a DAS remote machine, comprising:
the signal extraction module is used for extracting a second harmonic signal in the first channel signal;
the cancellation module is used for performing signal processing on the second harmonic signal extracted by the signal extraction module and then performing cancellation processing on the second harmonic signal of the first main channel signal to form a second main channel signal;
the detection module is used for detecting the cancellation effect of the second main channel signal to obtain a detection result;
and the processing module is used for receiving the detection result.
In a specific implementation process, as shown in fig. 2, which is a schematic block diagram inside the second harmonic cancellation device provided in this embodiment, the first main channel signal is a signal obtained by amplifying a main signal by a radio frequency module, the second harmonic signal is generated in an amplification process of the main signal by a radio frequency circuit, the signal extraction module extracts a second harmonic signal generated in the amplification process of the main signal by the radio frequency circuit and then sends the second harmonic signal to the cancellation module for cancellation processing, the cancellation processing is based on a principle that when two signals with completely communicated frequencies and amplitudes and completely opposite phases are synthesized, the two signals cancel each other, and the cancellation module generates a second main channel signal after cancellation processing is completed; the detection module extracts a second harmonic signal in the second main channel signal and detects the power of the second harmonic signal, the detection module transmits a detection result to the processing module after detection is completed, the processing module dynamically adjusts the cancellation module in real time according to the detection result, and the processing module can be a microprocessor MCU.
In one embodiment, the processing module is further configured to perform real-time amplitude modulation and/or phase modulation on the second harmonic signal according to the received detection result.
Specifically, the processing module may determine whether real-time amplitude modulation and/or phase modulation needs to be performed on the extracted second harmonic signal in the first main channel signal according to whether the detection result is greater than a preset threshold. The processing module judges whether the cancellation effect of the second harmonic signal does not cause interference to the uplink of other frequency bands according to the detection result of the detection module, the condition that the second harmonic signal causes interference to the uplink of other frequency bands can be that the second harmonic signal is larger than-80 dBm, and when the second harmonic signal in the second main path after cancellation processing is larger than-80 dBm, the processing module performs corresponding amplitude modulation and/or phase modulation on the cancellation module.
And carrying out real-time amplitude modulation or phase modulation on the second harmonic signal in the extracted first main channel signal according to the detection result, and offsetting the second harmonic signal in the extracted first main channel signal with the second harmonic signal in the first main channel signal after processing, so that the cancellation effect of the second harmonic signal is always in an optimal state.
In one embodiment, the signal extraction module includes a first coupler and a first filter, a main input end of the first coupler is used for accessing the first main path signal, a coupled output end of the first coupler is connected to an input end of the first filter, an output end of the first filter is connected to an input end of the cancellation module, an output end of the cancellation module is connected to a coupled input end of the first coupler, and a main output end of the first coupler is connected to the detection module.
Specifically, the first coupler couples the first main path signal and then filters the first main path signal by the first filter, and filters other signals which do not belong to the frequency range of the second harmonic signal, so as to extract the second harmonic signal.
The first coupler couples the main channel signals and then filters the main channel signals through the first filter, so that second harmonic signals in the first main channel signals are extracted, the second harmonic signals can be extracted through the existing coupler and the existing filter, and therefore the design difficulty and the design cost in the DAS equipment can be reduced.
In one embodiment, the signal extraction module further includes a limiter, the coupled output terminal of the first coupler is connected to the input terminal of the limiter, and the output terminal of the limiter is connected to the input terminal of the first filter.
Specifically, after the first coupler couples the first main path signal, the first coupler firstly transmits the first main path signal to the amplitude limiter to limit the amplitude of the coupled main path signal, removes a signal with higher power, and then transmits the first main path signal to the first filter to filter and extract a second harmonic signal.
The amplitude limiter is adopted to limit the main channel signal, and the signal with larger power is removed, so that the first coupler and the first filter extract more accurate second harmonic signals, and after amplitude limiting is carried out, the circuit devices connected subsequently can select a common model with small power.
In one embodiment, the cancellation module includes an amplitude modulator, a phase modulator, and a first amplifier, an input terminal of the amplitude modulator is connected to an output terminal of the first filter, an output terminal of the amplitude modulator is connected to an input terminal of the first amplifier, an output terminal of the first amplifier is connected to an input terminal of the phase modulator, and an output terminal of the phase modulator is connected to a coupling input terminal of the first coupler.
Specifically, a second harmonic signal extracted by a first filter in the signal extraction module is transmitted to an amplitude modulator, the amplitude modulator modulates the second harmonic signal and transmits the second harmonic signal to a first amplifier for amplification, and then transmits the second harmonic signal to a phase modulator for phase modulation, specifically, the frequency and amplitude of the second harmonic signal after amplitude modulation, amplification and phase modulation are the same as those of the second harmonic signal in the first main channel signal, and the phase of the second harmonic signal after amplitude modulation, amplification and phase modulation is opposite to that of the second harmonic signal in the first main channel signal; and transmitting the second harmonic signal subjected to amplitude modulation, amplification and phase modulation to a first coupler, coupling the second harmonic signal by the first coupler, injecting the second harmonic signal into a first main channel to be synthesized with the first main channel signal, and thus counteracting the second harmonic signal subjected to amplitude modulation, amplification and phase modulation with the second harmonic signal in the first main channel signal to complete cancellation processing.
Amplitude modulation, phase modulation and amplification processing are carried out on the second harmonic signals by adopting an amplitude modulator, an amplifier and a phase modulator, the second harmonic signals subjected to the amplitude modulation, the phase modulation and the amplification processing are injected into a first main channel through a first coupler and are synthesized with the first main channel signals, cancellation processing of the second harmonic signals is completed, and therefore the second harmonic signals in the first main channel signals are cancelled without interfering uplink of other frequency bands; the amplitude modulator, the amplifier, the phase modulator and the first coupler are used for finishing cancellation processing of second harmonic signals, and design difficulty and design cost of a radio frequency module of key parts in DAS equipment and power consumption of the whole machine are obviously reduced.
In one embodiment, the detection module comprises a load, a second coupler, a filter circuit, a detector and an analog-to-digital converter; the main input end of the second coupler is connected with the main output end of the first coupler, and the coupling input end of the second coupler is connected with a load;
the input end of the filter circuit is connected with the coupling output end of the second coupler and is used for filtering the coupled second main channel signal and extracting a new second harmonic signal;
the output end of the filter circuit is connected with the input end of the detector;
the output end of the detector is connected with the input end of the analog-to-digital converter and is used for detecting a new second harmonic signal formed by the filter circuit and transmitting a generated detection result to the analog-to-digital converter;
the output end of the analog-to-digital converter is connected with a processing module.
Specifically, the cancellation module generates a second main path signal after completing cancellation processing on the second harmonic signal, and a second coupler in the detection module couples the second main path signal and transmits the second main path signal to a filter circuit for filtering, so as to extract a new second harmonic signal, namely a residual second harmonic signal in the second main path signal; transmitting the extracted residual second harmonic signal to a detector for power detection and generating a detection result, wherein the detection result comprises amplitude information and the like of the residual second harmonic signal; and transmitting the detection result to an analog-to-digital converter for analog-to-digital conversion, so as to obtain the signal strength of the residual second harmonic signal, and transmitting the signal strength of the residual second harmonic signal to a processing module.
The second harmonic signal is extracted again from the second main channel signal which is already subjected to the cancellation processing, the extracted new second harmonic signal is sent to the detector to carry out power detection on the new second harmonic signal, so that the quality of the cancellation effect can be known, and the processing module can also carry out real-time dynamic adjustment on the cancellation processing according to the detection result after receiving the detection result, so that the cancellation effect of the second harmonic signal is always in the optimal state. .
In one embodiment, the filter circuit includes a second filter, an input terminal of the second filter is connected to the coupled output terminal of the second coupler, and an output terminal of the second filter is connected to an input terminal of the detector, and is configured to filter the coupled new main path signal and extract a new second harmonic signal.
Specifically, the cancellation module generates a second main path signal after performing cancellation processing on the second harmonic signal, and a second coupler in the detection module couples the second main path signal and transmits the second main path signal to a second filter for filtering, so as to extract a new second harmonic signal, that is, a residual second harmonic signal in the second main path signal.
And filtering the second main channel signal to extract an accurate new second harmonic signal.
In one embodiment, the filtering circuit further comprises a third filter and at least one second amplifier connected in series between the output of the second filter and the input of the third filter; the output end of the third filter is connected with the input end of the detector.
Specifically, the second main path signal is filtered by the second filter, then is subjected to signal amplification by the at least one second amplifier, and is subjected to secondary filtering by the third filter, so that the second main path signal is subjected to double filtering and amplification, and a more accurate and more complete new second harmonic signal is extracted.
In a specific implementation process, the number of the filters and the amplifiers in the filter circuit can be set to be one or more according to actual requirements.
And the second main channel signal is subjected to double filtering and amplification, so that a more accurate new second harmonic signal is extracted.
In one embodiment, the detection module further comprises a detection end limiter, and the second coupler and the filter circuit are connected through the detection end limiter.
Specifically, the second coupler couples the second main path signal, transmits the second main path signal to the amplitude limiter at the detection end for amplitude limiting, removes the signal with larger power, transmits the second main path signal to the second filter and the third filter for filtering, and extracts the second harmonic signal.
And the second main channel signal is subjected to amplitude limiting by adopting a detection end amplitude limiter, and a signal with larger power is removed, so that the second coupler and the filter circuit extract a more accurate new second harmonic signal, and after amplitude limiting, a circuit device connected subsequently can select a common model with small power.
In another embodiment, there is provided a second harmonic cancellation method for a DAS remote machine, for the cancellation apparatus, including the steps of:
extracting a second harmonic signal in the first main channel signal;
after the extracted second harmonic signal is subjected to signal processing, the second harmonic signal and a second harmonic signal of the first main channel signal are subjected to cancellation processing to form a second main channel signal;
extracting a second harmonic signal in the second main channel signal, carrying out power detection on the second harmonic signal in the second main channel signal and generating a detection result;
and dynamically adjusting the cancellation processing according to the detection result.
Specifically, the second main channel signal is a signal obtained by amplifying the main signal by the radio frequency module, the second harmonic signal is generated in the main signal amplification process by the radio frequency module, the cancellation device first extracts the second harmonic signal generated in the main signal amplification process by the radio frequency module and then performs cancellation processing, and the cancellation processing is based on the principle that when two signals with completely communicated frequencies and amplitudes and completely opposite phases are synthesized, the two signals are mutually cancelled, and the second main channel signal is generated after the cancellation processing is completed; and then, carrying out power detection on the cancellation effect of the second main channel signal, and dynamically adjusting cancellation processing in real time according to a detection result after the detection is finished.
The second harmonic signal of the first main channel signal is extracted, amplitude modulation and phase modulation are carried out on the second harmonic signal, and the second harmonic signal is synthesized with the second harmonic signal in the first main channel signal, so that the second harmonic signal in the first main channel signal is cancelled, and the problem that the second harmonic interferes with the uplink of other frequency bands is solved; the second main channel signal generated by the cancellation module is subjected to cancellation effect detection, and cancellation processing is dynamically adjusted in real time according to the detection result, so that the cancellation effect of the second harmonic signal is always in an optimal state.
In one embodiment, the cancellation processing is dynamically adjusted according to the detection result, namely real-time amplitude modulation and/or phase modulation is carried out on the second harmonic signal according to the detection result.
Specifically, whether real-time amplitude modulation and/or phase modulation needs to be performed on the second harmonic signal can be judged according to whether the detection result is greater than a preset threshold value. And judging whether the cancellation effect of the second harmonic signal can not cause interference on the uplink of other frequency bands according to the detection result, wherein the condition that the second harmonic signal causes interference on the uplink of other frequency bands can be that the second harmonic signal is larger than-80 dBm, and when the second harmonic signal in the second main path after cancellation processing is larger than-80 dBm, performing corresponding amplitude modulation and/or phase modulation on the extracted second harmonic in the first main path signal.
And carrying out real-time amplitude modulation or phase modulation on the second harmonic signal according to the detection result, so that the second harmonic signal is counteracted with the second harmonic signal in the first main channel signal, and the cancellation effect of the second harmonic signal is always in an optimal state.
In one embodiment, the extracting the second harmonic signal in the main path signal is performed by using a first coupler and a first filter; the second main channel signal formed by performing cancellation processing on the second harmonic signal is the second harmonic signal which is subjected to cancellation processing by adopting an amplitude modulator, a phase modulator and an amplifier; the detection for the cancellation effect of the second main channel signal and the generation of the detection result are carried out by adopting a second coupler, a filter circuit, an amplifier, a detector and an analog-to-digital converter; and the dynamic adjustment of the cancellation processing according to the detection result is to adopt a processing module to dynamically adjust the cancellation processing.
In a specific implementation process, a first coupler couples a main channel signal, then filters the main channel signal by a first filter, and filters other signals which do not belong to the frequency range of a second harmonic signal, so as to extract a second harmonic signal, the second harmonic signal is transmitted to an amplitude modulator, the amplitude modulator modulates the second harmonic signal, then transmits the second harmonic signal to an amplifier for amplification, and then transmits the second harmonic signal to a phase modulator for phase modulation of the second harmonic signal, specifically, the frequency and amplitude of the second harmonic signal after amplitude modulation, amplification and phase modulation are the same as those of the second harmonic signal in the main channel signal, and the phase of the second harmonic signal after amplitude modulation, amplification and phase modulation is opposite to those of the second harmonic signal in the main channel signal; transmitting the amplitude-modulated, amplified and phase-modulated second harmonic signal to a first coupler, coupling the second harmonic signal by the first coupler, injecting the second harmonic signal into a first main path to be synthesized with the first main path signal, so that the amplitude-modulated, amplified and phase-modulated second harmonic signal is counteracted with the second harmonic signal in the first main path signal to complete cancellation processing, coupling the second main path signal subjected to the cancellation processing again by a second coupler and filtering by a filter circuit to extract a residual second harmonic signal, transmitting the residual second harmonic signal to a detector to perform power detection to generate a detection result, wherein the detection result comprises amplitude information and the like of the residual second harmonic signal; and transmitting the detection result to an analog-to-digital converter for analog-to-digital conversion, so as to obtain the signal strength of the residual second harmonic signal, and transmitting the signal strength of the residual second harmonic signal to a processing module.
The second harmonic signal is extracted and canceled by adopting the first coupler, the first filter, the amplitude modulator, the phase modulator and the amplifier, the cancellation result is detected by adopting the wave detector and the amplitude modulator and the phase modulator are dynamically adjusted by adopting the processing module, the cancellation of the second harmonic signal is realized, and the cancellation result is always in the optimal state, so that the problem that the second harmonic signal interferes the uplink of other frequency bands is solved.
Example 2
In another embodiment, there is provided a DAS remote using the second harmonic cancellation apparatus as described above, as shown in fig. 3, which is a schematic block diagram of the DAS remote, and includes a digital module, a radio frequency module, and a multi-frequency combiner, and further includes the cancellation apparatus described above, where the digital module is connected to the radio frequency module and is used to process signals; the radio frequency module is connected with the multi-frequency combiner and is used for amplifying signals and power; the cancellation device is connected with the radio frequency module and is used for canceling a second harmonic signal generated in the process that the radio frequency module amplifies signals and power; the multi-frequency combiner is connected with the cancellation device and used for suppressing the second harmonic signals after cancellation.
In a specific implementation process, the DAS remote machine is a dual-frequency (CDMA800 and DCS1800) high-power DAS remote machine, and mainly includes a digital module, a radio frequency module, a cancellation device, a multi-frequency combiner, and a power supply. The digital module is connected with an optical transceiver unit and a radio frequency module in the DAS system and mainly undertakes signal processing work; the radio frequency module is respectively connected with the digital module and the multi-frequency combiner and mainly used for amplifying signals and power; the cancellation device is connected with the radio frequency module and used for canceling a second harmonic signal generated in the process that the radio frequency module amplifies signals and power, and ensuring that the second harmonic signal generated by the radio frequency module does not interfere with the uplink of a DCS1800 frequency band; the second power supply module mainly supplies power to the radio frequency module and the digital module; the multi-frequency combiner is used for completing the combination and separation of signals of all paths, realizing the frequency band isolation among all ports and realizing the suppression of second harmonic signals; and finally, the multi-frequency combiner is connected with the antenna, and the antenna completes the transmission and the reception of signals.
The working principle of the dual-frequency (CDMA800 and DCS1800) high-power DAS remote machine is as follows: the uplink operating frequency band of CDMA800 is: 825-835Mz, the downlink working frequency band is: 870 and 880 MHz; the uplink working frequency band of the DCS1800 is as follows: 1710-: 1805-1880 MHz; obviously, the second harmonic (1740-.
The working principle of a downlink is as follows: an optical signal containing CDMA800 and DCS1800 information is transmitted to an optical transceiver unit from an upper-level device through an optical fiber, the optical transceiver unit converts the optical signal into an electrical signal, a digital module separates the frequency band of the received electrical signal into two downlink signals of CDMA800 and DCS1800, then the two downlink signals of CDMA800 and DCS1800 enter a radio frequency module after being respectively subjected to relevant processing such as filtering, digital-to-analog conversion, modulation and the like, the radio frequency module respectively amplifies the power of two downlink radio frequency signals of CDMA800 and DCS1800, then the downlink radio frequency signal of DCS1800 is directly transmitted to a multi-frequency combiner, as the radio frequency module also generates a second harmonic product of the CDMA800 downlink signal while amplifying the CDMA800 downlink signal, in order to prevent the second harmonic of the CDMA800 downlink signal from directly entering an uplink channel of DCS1800 to seriously interfere with the uplink channel of DCS1800, a cancellation device firstly processes the second harmonic and then transmits the CDMA800 downlink signal to the multi-frequency combiner, the multi-frequency combiner combines two paths of downlink signals and then sends the combined signals to an antenna to be transmitted, so that the secondary harmonic signals are prevented from interfering uplink of other frequency bands.
The cancellation device is adopted to cancel the second harmonic signal generated by the radio frequency module, so that a good cancellation effect is realized, and the suppression of the rear-stage multi-frequency combiner is added, so that the second harmonic signal generated by the radio frequency module can not interfere the uplink of other frequency bands; moreover, the cancellation device does not cause the attenuation of the main channel signal in the process of canceling the second harmonic signal, so that the design difficulty and the design cost of a radio frequency module of a key component in DAS equipment and the power consumption of a whole machine can be reduced; in addition, the cancellation device can be integrated into the radio frequency module to realize an integrated design, so that the volume of the DAS equipment is reduced.
It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific embodiments of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention claims should be included in the protection scope of the present invention claims.
Claims (10)
1. A second harmonic cancellation apparatus for a DAS remote machine, comprising:
the signal extraction module is used for extracting a second harmonic signal in the first main channel signal;
the cancellation module is used for performing signal processing on the second harmonic signal extracted by the signal extraction module and then performing cancellation processing on the second harmonic signal of the first main channel signal to form a second main channel signal;
the detection module is used for detecting the cancellation effect of the second main channel signal to obtain a detection result;
the processing module is used for receiving the detection result;
the detection module comprises a load, a second coupler, a filter circuit, a detector and an analog-to-digital converter; the main input end of the second coupler is connected with the main output end of the first coupler of the signal extraction module, and the coupling input end of the second coupler is connected with a load;
the input end of the filter circuit is connected with the coupling output end of the second coupler and is used for filtering the coupled second main channel signal and extracting a residual second harmonic signal;
the output end of the filter circuit is connected with the input end of the detector;
the output end of the detector is connected with the input end of the analog-to-digital converter and used for detecting residual second harmonic signals formed by the filter circuit and transmitting generated detection results to the analog-to-digital converter;
the output end of the analog-to-digital converter is connected with the processing module.
2. The second harmonic cancellation apparatus according to claim 1, wherein the processing module is further configured to perform real-time amplitude modulation and/or phase modulation on the second harmonic signal according to the received detection result.
3. The second harmonic cancellation apparatus according to claim 1, wherein the signal extraction module further includes a first filter, a main input terminal of the first coupler is configured to be connected to the first main path signal, a coupled output terminal of the first coupler is connected to an input terminal of the first filter, an output terminal of the first filter is connected to an input terminal of the cancellation module, an output terminal of the cancellation module is connected to a coupled input terminal of the first coupler, and a main output terminal of the first coupler is connected to the detection module.
4. The second harmonic cancellation apparatus according to claim 3, wherein the signal extraction module further comprises a limiter, the coupled output terminal of the first coupler is connected to the input terminal of the limiter, and the output terminal of the limiter is connected to the input terminal of the first filter.
5. The second harmonic cancellation apparatus according to claim 3, wherein the cancellation module includes an amplitude modulator, a phase modulator and a first amplifier, an input terminal of the amplitude modulator is connected to an output terminal of the first filter, an output terminal of the amplitude modulator is connected to an input terminal of the first amplifier, an output terminal of the first amplifier is connected to an input terminal of the phase modulator, and an output terminal of the phase modulator is connected to a coupling input terminal of the first coupler.
6. The second harmonic cancellation apparatus according to claim 1, wherein the filter circuit includes a second filter, an input terminal of the second filter is connected to the coupled output terminal of the second coupler, and an output terminal of the second filter is connected to an input terminal of the detector, and is configured to filter the coupled new main path signal and extract a residual second harmonic signal.
7. The second harmonic cancellation apparatus for a DAS remote machine of claim 6, wherein the filter circuit further comprises a third filter and at least one second amplifier connected in series between the output of the second filter and the input of the third filter;
the output end of the third filter is connected with the input end of the detector.
8. A second harmonic cancellation method is applied to a DAS remote machine and comprises the following steps:
extracting a second harmonic signal in the first main channel signal;
after the extracted second harmonic signal is subjected to signal processing, the second harmonic signal and a second harmonic signal in the first main channel signal are subjected to cancellation processing to form a second main channel signal;
performing second coupler coupling and filtering of the filter circuit on the second main path signal subjected to cancellation processing again to extract a residual second harmonic signal;
transmitting the residual second harmonic signal to a detector for power detection to generate a detection result;
transmitting the detection result to an analog-to-digital converter for analog-to-digital conversion;
and dynamically adjusting the cancellation processing according to the detection result.
9. The method of claim 8, wherein dynamically adjusting the cancellation process according to the detection result is real-time amplitude modulating and/or phase modulating the second harmonic signal in the extracted first main channel signal according to the detection result.
10. A DAS remote using the second harmonic cancellation apparatus of any one of claims 1 to 7, comprising a digital module, a radio frequency module, and a multi-frequency combiner, further comprising the cancellation apparatus of any one of claims 1 to 7, wherein the digital module is connected to the radio frequency module for processing signals; the radio frequency module is connected with the multi-frequency combiner and is used for amplifying signals and power; the cancellation device is connected with the radio frequency module and is used for canceling a second harmonic signal generated in the process that the radio frequency module amplifies signals and power; the multi-frequency combiner is connected with the cancellation device and used for suppressing the second harmonic signals after cancellation.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105406924A (en) * | 2015-09-25 | 2016-03-16 | 广州埃信电信设备有限公司 | Multi-frequency-band digital distributed antenna system |
| CN106685442A (en) * | 2016-12-29 | 2017-05-17 | 北京裕源大通科技股份有限公司 | Second harmonic anti-phase offset function circuit |
| CN109327230A (en) * | 2018-11-29 | 2019-02-12 | 京信通信系统（中国）有限公司 | A kind of method, apparatus and DAS system of digital analogue signal mixed transport |
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| CN202587393U (en) * | 2012-03-30 | 2012-12-05 | 京信通信系统（中国）有限公司 | Device for realizing multi-frequency broadband high-speed digital distributed antenna system (DAS) |
| US9603155B2 (en) * | 2015-07-31 | 2017-03-21 | Corning Optical Communications Wireless Ltd | Reducing leaked downlink interference signals in a remote unit uplink path(s) in a distributed antenna system (DAS) |
| CN106912069B (en) * | 2017-03-24 | 2019-12-10 | 京信通信系统（中国）有限公司 | Distributed antenna system remote terminal and uplink signal link detection method and device thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105406924A (en) * | 2015-09-25 | 2016-03-16 | 广州埃信电信设备有限公司 | Multi-frequency-band digital distributed antenna system |
| CN106685442A (en) * | 2016-12-29 | 2017-05-17 | 北京裕源大通科技股份有限公司 | Second harmonic anti-phase offset function circuit |
| CN109327230A (en) * | 2018-11-29 | 2019-02-12 | 京信通信系统（中国）有限公司 | A kind of method, apparatus and DAS system of digital analogue signal mixed transport |
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