CN111162808A - Radio frequency receiving circuit, receiver and base station - Google Patents
Radio frequency receiving circuit, receiver and base station Download PDFInfo
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- CN111162808A CN111162808A CN201911424135.XA CN201911424135A CN111162808A CN 111162808 A CN111162808 A CN 111162808A CN 201911424135 A CN201911424135 A CN 201911424135A CN 111162808 A CN111162808 A CN 111162808A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/16—Circuits
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
- H04W88/08—Access point devices
Abstract
The invention relates to a radio frequency receiving circuit, a receiver and a base station. The radio frequency receiving circuit comprises a duplexer, an integrated amplitude limiter, a low noise amplifier, a band-pass filter and a transceiving unit. The common port of the duplexer is used for electrically connecting the base station antenna. The duplexer, the integrated amplitude limiter, the low-noise amplifier, the band-pass filter and the receiving and transmitting unit are sequentially cascaded. The integrated amplitude limiter is used for carrying out amplitude limiting on common-frequency large signals in the received signals output by the duplexer; the signal amplitude of the amplitude limited common-frequency large signal is lower than the saturation threshold of the low-noise amplifier. Through the link structure design, the integrated amplitude limiter is used for amplitude limiting of the same-frequency large signal, so that after the same-frequency large signal is subjected to amplitude limiting, the signal amplitude of the same-frequency large signal is lower than the saturation threshold of the low-noise amplifier, and the low-noise amplifier is effectively prevented from being saturated; meanwhile, the insertion loss introduced by the integrated amplitude limiter is small, and the useful signals in the small-amplitude signals cannot be influenced, so that the aim of preventing the performance of the receiver from being damaged is fulfilled.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a radio frequency receiving circuit, a receiver, and a base station.
Background
With the development of mobile communication technology, the communication environment becomes more complex, the types of signals existing in space become more various, and the performance requirements on the receiver of the base station become more strict. At the receiver of the base station, if the large amplitude signal enters the receiver directly, there is a possibility that the hardware link of the receiver is damaged. When a hardware link of the receiver is partially damaged, the base station cannot work normally, user communication in an area covered by the base station is seriously affected, and maintenance cost is generated for the base station in a later period. It is therefore important to protect the hardware link of the receiver of the base station.
In a communication system with a terminal and a base station close to each other, the transmitting frequency point of the terminal is just the receiving frequency point of the base station, so that co-channel interference can be generated in the process of simultaneous working of the terminal and the base station. The isolation of the antennas of the base station is limited and large interfering signals of the same frequency will damage the electronics in the hardware link of the receiver. The traditional receiver protection method is to design a special amplitude limiting protection circuit to carry out amplitude limiting on all input signals. However, in the process of implementing the present invention, the inventor finds that the conventional receiver protection mode has a problem that the performance of the receiver is damaged for a communication system in which the terminal and the base station are close to each other.
Disclosure of Invention
In view of the above, it is necessary to provide a radio frequency receiving circuit, a receiver and a base station device capable of effectively avoiding the performance of the receiver from being damaged in view of the above-mentioned problems in the conventional receiver protection method.
In order to achieve the above object, the embodiments of the present invention provide the following technical solutions:
on one hand, the embodiment of the invention provides a radio frequency receiving circuit, which comprises a duplexer, an integrated amplitude limiter, a low-noise amplifier, a band-pass filter and a receiving and transmitting unit;
the common port of the duplexer is used for electrically connecting the base station antenna, and the duplexer, the integrated amplitude limiter, the low-noise amplifier, the band-pass filter and the receiving and transmitting unit are sequentially cascaded;
the integrated amplitude limiter is used for carrying out amplitude limiting on common-frequency large signals in the received signals output by the duplexer; the signal amplitude of the amplitude limited common-frequency large signal is lower than the saturation threshold of the low-noise amplifier.
In one embodiment, the rf receiving circuit further includes an adjustable gain control unit, and the low noise amplifier is connected to the band pass filter through the adjustable gain control unit;
the adjustable gain control unit is used for carrying out gain adjustment on a small-amplitude signal in a receiving signal output by the low-noise amplifier; the power of the small amplitude signal after the gain adjustment is lower than the ADC overflow threshold of the transceiving unit.
In one embodiment, the adjustable gain control unit comprises a controller and a controllable gain circuit, and the low noise amplifier is connected to the band-pass filter through the controllable gain circuit;
the control output end of the controller is electrically connected with the gain control end of the controllable gain circuit, the power supply end of the controller is used for electrically connecting a power supply source, and the controller is used for adjusting the output gain of the controllable gain circuit;
the controllable gain circuit is used for detecting the power of the small-amplitude signal output by the low-noise amplifier and outputting the power to the controller, and adjusting the power of the small-amplitude signal.
In one embodiment, the adjustable gain control unit comprises a detection circuit, a controller and a controllable gain circuit;
the detection circuit is cascaded with the controllable gain circuit, and the low-noise amplifier is connected to the band-pass filter through the detection circuit and the controllable gain circuit;
the power supply end of the controller is used for being electrically connected with a power supply source, the detection input end of the controller is electrically connected with the detection output end of the detection circuit, and the control output end of the controller is electrically connected with the gain control end of the controllable gain circuit;
the detection circuit is used for detecting the power of the small-amplitude signal output by the low-noise amplifier and outputting the power to the controller, the controller is used for adjusting the output gain of the controllable gain circuit, and the controllable gain circuit is used for adjusting the power of the small-amplitude signal.
In one embodiment, the controller comprises an FPGA chip, a CPLD device, or a single chip.
In one embodiment, the controllable gain circuit includes an adjustable gain amplifier or an adjustable power attenuator.
In one embodiment, the transceiver unit is further configured to perform gain adjustment on a small-amplitude signal in the received signal output by the band-pass filter; the power of the small amplitude signal after the gain adjustment is lower than the ADC overflow threshold of the transceiving unit.
In another aspect, a receiver is also provided, which includes the above radio frequency receiving circuit.
In still another aspect, a base station is also provided, which includes a base station antenna and the above receiver.
In one embodiment, the base station is an NB-IOT base station.
One of the above technical solutions has the following advantages and beneficial effects:
according to the radio frequency receiving circuit, the receiver and the base station, through the link structure design of the duplexer, the integrated amplitude limiter, the low-noise amplifier, the band-pass filter and the receiving and transmitting unit, the received signal output by the base station antenna enters the radio frequency receiving circuit through the duplexer, and when the received signal contains large-amplitude same-frequency large signals, the integrated amplitude limiter can limit the amplitude of the same-frequency large signals, so that the signal amplitude of the same-frequency large signals is lower than the saturation threshold of the low-noise amplifier after the amplitude limiting. Therefore, when a same-frequency large signal sent by a terminal is received, the saturation of the low-noise amplifier can be effectively avoided through the amplitude limiting of the integrated amplitude limiter, so that the effect of protecting the low-noise amplifier is achieved, and the overflow of an ADC (analog-to-digital converter) of a rear-stage receiving and sending unit is avoided. Meanwhile, the insertion loss introduced by the integrated amplitude limiter is small, and the integrated amplitude limiter does not limit the small-amplitude signal, so that the useful signal in the small-amplitude signal in the received signal is not affected, and the purpose of avoiding the performance damage of the receiver is achieved.
Drawings
FIG. 1 is a schematic diagram of a first structure of an RF receiver circuit according to an embodiment;
fig. 2 is a diagram illustrating the clipping performance curve of the integrated clipper in one embodiment;
FIG. 3 is a diagram illustrating a second exemplary architecture of an RF receiver circuit;
FIG. 4 is a diagram illustrating a third exemplary embodiment of an RF receiver circuit;
FIG. 5 is a diagram illustrating a fourth exemplary architecture of an RF receiver circuit;
fig. 6 is a schematic diagram of an application of a base station in one embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application. It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element and integrated therewith or intervening elements may be present, i.e., indirectly connected to the other element.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Referring to fig. 1 and fig. 2, an embodiment of the invention provides a radio frequency receiving circuit 100, which includes a duplexer 12, an integrated limiter 14, a low noise amplifier 16, a band pass filter 18, and a transceiver unit 19. The common port of the duplexer 12 is used to electrically connect the base station antenna 101. The duplexer 12, the integrated limiter 14, the low noise amplifier 16, the band pass filter 18, and the transceiver unit 19 are sequentially cascaded. The integrated limiter 14 is configured to limit the same-frequency large signal in the received signal output by the duplexer 12. The amplitude of the amplitude-limited common-frequency large signal is lower than the saturation threshold of the low noise amplifier 16.
It is understood that the duplexer 12 refers to a duplexer 12 commonly used in the art, and is used for enabling the rf receiving circuit and the rf transmitting circuit of the base station to access the base station antenna 101, respectively. The integrated limiter 14 may be any type of integrated limiting chip available on the market, and the specific type may be determined according to the actual application scenario, in order to protect the signal limiting capability that the low noise amplifier 16 needs to provide, as long as the level of the limited output signal does not cause saturation of the low noise amplifier 16. The low noise amplifier 16 refers to a low noise amplifier 16 used in a radio frequency receiving link of a base station in a communication system where a terminal and the base station coexist, and is configured to amplify a received signal output by the integrated limiter 14, where the low noise amplifier 16 may be any conventional type of low noise amplifier 16, and may be specifically determined by a type of the low noise amplifier 16 specifically used in the radio frequency receiving link of the base station in an actual application scenario.
The band-pass filter 18 and the transceiver unit 19 are link devices used in a radio frequency reception link of a base station in a communication system in which a terminal and the base station coexist. The band-pass filter 18 is used to provide a post-filtering function of the low noise amplifier 16, and the transceiver unit 19 is used to provide functions of receiving processing and transmitting processing of uplink/downlink signals of the base station, which can be understood by referring to the transceiver unit 19 used in a hardware link of a receiver of a conventional base station. The saturation threshold refers to a signal amplitude threshold that causes the low noise amplifier 16 to enter a saturation state from a normal operating state. Where TX in fig. 1 denotes a transmitter output port of the base station.
Specifically, in an actual application scenario, the distance between the terminal and the base station is short, so that a communication system in which the terminal and the base station coexist is formed. When the terminal and the base station work simultaneously, the base station can just receive the transmitting signals of the terminal at the same frequency point, and the transmitting signals of the terminal are received by the base station antenna 101 due to the limited isolation provided by the base station antenna 101, so that the same-frequency large signals with larger signal amplitude can be formed. When the received signal entering through the base station antenna 101 is a common-frequency large signal sent by the terminal, if the signal amplitude of the common-frequency large signal exceeds the low-noise saturation threshold, the common-frequency large signal directly enters the low-noise amplifier 16 after being output from the duplexer 12, so that the low-noise amplifier 16 enters a saturation state and damages the low-noise amplifier 16.
The integrated amplitude limiter 14 selected according to the saturation threshold of the low noise amplifier 16 is connected between the duplexer 12 and the low noise amplifier 16, so that when the received signal is mainly a same-frequency large signal, the integrated amplitude limiter 14 limits the amplitude of the same-frequency large signal with a larger signal amplitude, and limits the signal amplitude of the same-frequency large signal to be below the saturation threshold of the low noise amplifier 16, thereby preventing the low noise amplifier 16 from being saturated when the received signal enters the low noise amplifier 16 for amplification. Received signals in different time periods can be different, and only the integrated amplitude limiter 14 needs to limit amplitude of common-frequency large signals through selection of the integrated amplitude limiter 14, and when small-amplitude signals are input, the integrated amplitude limiter 14 does not limit the small-amplitude signals, so that useful signals contained in the small-amplitude signals cannot be influenced. Fig. 2 shows a clipping performance curve of one of the integrated limiters 14 in practical application, and by applying such an integrated limiter 14 or an integrated limiter with similar output performance, clipping processing on a large signal with the same frequency can be effectively achieved without limiting the effect of a small signal. Two curves, 005 and 007, respectively show two different clipping performances.
According to the radio frequency receiving circuit 100, through the link structure design of the duplexer 12, the integrated amplitude limiter 14, the low noise amplifier 16, the band pass filter 18 and the transceiving unit 19, the received signal output by the base station antenna 101 enters the radio frequency receiving circuit 100 through the duplexer 12, and when the received signal contains a large-amplitude same-frequency large signal, the integrated amplitude limiter 14 limits the amplitude of the same-frequency large signal, so that the signal amplitude of the same-frequency large signal is lower than the saturation threshold of the low noise amplifier 16 after the amplitude of the same-frequency large signal is limited. Therefore, when receiving a common-frequency large signal sent by the terminal, the integrated amplitude limiter 14 limits the amplitude, which can effectively avoid causing the saturation of the low noise amplifier 16, thereby achieving the effect of protecting the low noise amplifier 16 and avoiding causing the overflow of the ADC (analog-to-digital converter) of the rear-stage transceiver unit 19. Meanwhile, the insertion loss introduced by the integrated amplitude limiter 14 is small, and the integrated amplitude limiter 14 does not limit the small-amplitude signal, so that the useful signal in the small-amplitude signal in the received signal is not affected, and the purpose of avoiding the performance damage of the receiver is achieved.
In one embodiment, the transceiver unit 19 is further configured to perform gain adjustment on a small-amplitude signal in the received signal output by the band-pass filter 18. The power of the gain-adjusted small-amplitude signal is lower than the ADC overflow threshold of the transceiving unit 19.
It can be understood that, when the signal power of the received signal input to the transceiver unit 19 exceeds the ADC overflow threshold, the ADC of the transceiver unit 19 overflows, so that the internal circuits of the transceiver unit 19, such as the filter, the mixer and the ADC device, are damaged, and the rf receiving circuit 100 is damaged. In the art, the transceiver unit 19 of the base station is an integrated system on chip, and various processing units, such as but not limited to a baseband processing unit, a mixing unit and a filtering unit, are integrated inside the integrated system on chip, which may be determined according to the specific type of the transceiver unit 19 actually equipped in the receiver of the base station in practical applications.
The transceiver unit 19 may generally be configured in advance, for example, by enabling an Automatic Gain Control (AGC) function of the transceiver unit 19, so that for a small signal entering the transceiver unit 19, the transceiver unit 19 performs automatic gain adjustment through an automatic gain control function compatible with itself, thereby ensuring that the ADC module inside the transceiver unit 19 does not generate overflow. Specifically, in this embodiment, the transceiver unit 19 may further implement an uplink automatic gain control function compatible with the transceiver unit 19 to automatically perform signal power detection on the small-amplitude signal output by the band-pass filter 18, and automatically adjust a link gain, such as a backoff link gain, inside the transceiver unit 19 based on the detected signal power, so that the power of the small-amplitude signal whose signal power is higher than the ADC overflow threshold is attenuated to below the ADC overflow threshold.
Therefore, the transceiver unit 19 adjusts the gain of the small-amplitude signal through the above-mentioned automatic gain control function when the signal power of the small-amplitude signal is too high, so as to attenuate the signal power of the small-amplitude signal, and ensure that the signal power is within the power range allowed by each device when the small-amplitude signal enters the filter, the mixer, the ADC, and other devices inside the transceiver unit 19, thereby avoiding the ADC from overflowing to ensure the blocking performance of the transceiver unit 19, and further avoiding the performance of the receiver from being damaged while further protecting the device safety of the rf receiving circuit 100.
Referring to fig. 3, in an embodiment, the rf receiving circuit 100 further includes an adjustable gain control unit 17. The low noise amplifier 16 is connected to a band pass filter 18 through an adjustable gain control unit 17. The adjustable gain control unit 17 is configured to perform gain adjustment on a small-amplitude signal in the received signal output by the low noise amplifier 16. The power of the gain-adjusted small-amplitude signal is lower than the ADC overflow threshold of the transceiving unit 19.
It is understood that the adjustable gain control unit 17 refers to a signal gain circuit or a signal attenuation circuit with controllable output gain, and may be various gain adjustable devices or circuit modules commonly used in the field of radio frequency links. The adjustable gain control unit 17 may directly sample the output signal from the output terminal of the low noise amplifier 16 to obtain the signal power of the received signal output by the low noise amplifier 16; the adjustable gain control unit 17 may also obtain the signal power of the received signal entering the transceiver unit 19 by receiving the signal power output by the transceiver unit 19, for example, the transceiver unit 19 obtains the signal power of the input signal by an internally integrated signal detection function and outputs the signal power to the adjustable gain control unit 17. The adjustable gain control unit 17 may also obtain the signal power of the received signal output by the low noise amplifier 16 by receiving the output power of an external separately provided signal sampling device (e.g., a signal sampler additionally provided at the receiver of the base station). The specific implementation manner of obtaining the signal power of the received signal at the post-stage of the low noise amplifier 16 by the adjustable gain control unit 17 may be determined according to the specific type of the adjustable gain control unit 17 or the specific type of the receiver used in the actual application scenario.
Specifically, in the present embodiment, the adjustable gain control unit 17 is connected between the low noise amplifier 16 and the band pass filter 18, and the adjustable gain control unit 17 performs gain adjustment on the small amplitude signal output from the low noise amplifier 16. When the signal power of the small-amplitude signal after passing through the low noise amplifier 16 still exceeds the ADC overflow threshold of the transceiver unit 19, the adjustable gain control unit 17 automatically backs off the gain, so that the power of the small-amplitude signal whose signal power is higher than the ADC overflow threshold is attenuated to below the ADC overflow threshold. The manner in which the adjustable gain control unit 17 automatically adjusts the gain can be similarly understood with reference to various gain adjustment manners commonly used in the art.
Therefore, the gain of the small-amplitude signal passing through the low-noise amplifier 16 is automatically adjusted by the adjustable gain control unit 17, so that the signal power attenuation of the small-amplitude signal is realized when the signal power of the small-amplitude signal is too high, and after the small-amplitude signal enters the transceiver unit 19, the signal power of the small-amplitude signal is within the power range allowed by each device of the internal link of the transceiver unit 19, thereby avoiding the overflow of the ADC, ensuring the blocking performance of the transceiver unit 19, further protecting the device safety of the radio frequency receiving circuit 100, and further avoiding the performance damage of the receiver.
Referring to fig. 4, in one embodiment, the adjustable gain control unit 17 includes a controller 172 and a controllable gain circuit 174. The low noise amplifier 16 is connected to the band pass filter 18 through a controllable gain circuit 174. A control output of the controller 172 is electrically connected to a gain control terminal of the controllable gain circuit 174. The power supply terminal of the controller 172 is used for electrically connecting to a power supply source. The controller 172 is used to adjust the output gain of the controllable gain circuit 174. The controllable gain circuit 174 is used for detecting the power of the small-amplitude signal output from the low noise amplifier 16 and outputting the detected power to the controller 172, and adjusting the power of the small-amplitude signal.
It is understood that the controller 172 may be a gain adjustment control circuit known in the art, or may be a separately provided gain controller 172 or a main controller 172 of the receiver, and may be determined according to the type of the base station structure or the application cost in practical application. The signal power comparison and gain adjustment command output functions implemented by the controller 172 may be gain adjustment functions known in the art. The power supply is a power supply for supplying power required by the controller 172 to operate normally, and may be a power supply of the receiver, or may be an independent power supply, such as but not limited to a rechargeable battery, a solar battery, or a non-rechargeable battery. The particular type of power supply may be determined based on the power requirements of the controller 172 actually selected.
The controllable gain circuit 174 may be various types of controllable gain devices with integrated signal power detection functions in the art, and the controllable gain circuit 174 may sample a received signal in real time and output the sampled signal or signal power to the controller 172 while transmitting the received signal at a certain gain, so that the controller 172 reads the signal power of the sampled signal or directly receives the signal power for generating a corresponding gain control signal.
Specifically, in the working process of the base station, after the controller 172 is powered on to work, the signal power of the small-amplitude signal output by the low noise amplifier 16 may be obtained in real time, and the obtained signal power is compared with the pre-stored ADC overflow threshold. When the signal power is greater than the ADC overflow threshold, a gain adjustment signal is output to the controllable gain circuit 174 to back off the output gain of the controllable gain circuit 174. At this time, the signal power of the small-amplitude signal passing through the controllable gain circuit 174 is attenuated to be below the ADC overflow threshold of the transceiver unit 19 due to the output gain back-off of the controllable gain circuit 174, so as to ensure that the small-amplitude signal finally entering the transceiver unit 19 does not cause ADC overflow.
Through the arrangement of the controller 172 and the controllable gain circuit 174, in cooperation with the integrated limiter 14, the protection of the low noise amplifier 16 is achieved, and meanwhile, the link devices at the rear stage of the low noise amplifier 16 are more effectively protected, and the blocking performance of the applied receiver is ensured.
Referring to fig. 5, in one embodiment, the adjustable gain control unit 17 includes a detection circuit 171, a controller 172, and a controllable gain circuit 174. The detector circuit 171 is cascaded with the controllable gain circuit 174. The low noise amplifier 16 is connected to the band pass filter 18 through the detector circuit 171 and the controllable gain circuit 174. The power supply terminal of the controller 172 is used for electrically connecting to a power supply source. The detection input terminal of the controller 172 is electrically connected to the detection output terminal of the detector circuit 171. A control output of the controller 172 is electrically connected to a gain control terminal of the controllable gain circuit 174. The detector circuit 171 detects the power of the small-amplitude signal output from the low noise amplifier 16 and outputs the detected power to the controller 172. The controller 172 is used to adjust the output gain of the controllable gain circuit 174. The controllable gain circuit 174 is used to adjust the power of the small amplitude signal.
It is understood that the detection circuit 171 is a circuit for sampling the power of the received signal output from the low noise amplifier 16, and may be any type of signal power sampling device commonly used in the art. For the explanation of the controller 172 in this embodiment, the same principle can be understood by specifically referring to the explanation of the controller 172 in the foregoing embodiment, and the description is not repeated here. In this embodiment, the controllable gain circuit 174 may be a signal gain device with controllable output gain of various types that do not integrate signal power detection functions in the art.
Specifically, in the operation process of the base station, after the controller 172 is powered on to operate, the signal power of the small-amplitude signal output by the low noise amplifier 16 can be obtained in real time through the detection circuit 171, and the obtained signal power is compared with the pre-stored ADC overflow threshold. When the signal power is greater than the ADC overflow threshold, a gain adjustment signal is output to the controllable gain circuit 174 to back off the output gain of the controllable gain circuit 174. At this time, the signal power of the small-amplitude signal passing through the controllable gain circuit 174 is attenuated to be below the ADC overflow threshold of the transceiver unit 19 due to the output gain back-off of the controllable gain circuit 174, so as to ensure that the small-amplitude signal finally entering the transceiver unit 19 does not cause ADC overflow.
By the arrangement of the detector circuit 171, the controller 172 and the controllable gain circuit 174, in cooperation with the integrated limiter 14, the protection of the low noise amplifier 16 is realized, and meanwhile, the link device at the rear stage of the low noise amplifier 16 can be more effectively protected, so as to ensure the blocking performance of the applied receiver.
In one embodiment, the controller 172 comprises an FPGA chip, a CPLD device, or a single chip. It is understood that an FPGA chip or a CPLD device may be used as the controller 172 for adjusting the output gain of the controllable gain circuit 174, wherein the FPGA chip or the CPLD device may be a chip or a device applied independently or a chip or a device applied in an embedded manner, and may be determined according to the type of the receiver applied in practice, as long as the required gain adjustment function can be provided. In addition, a single chip microcomputer can be used as the controller 172 for adjusting the output gain of the controllable gain circuit 174, and the specific type can be selected according to the installation mode, maintenance and other needs of practical application as long as the required gain adjustment function can be provided.
By applying the FPGA chip, the CPLD device or the single chip microcomputer, the output gain of the controllable gain circuit 174 is adjusted, the circuit can be accessed to a link for use after being purchased directly, additional development is not needed, the application cost is low, the reliability is high, the application and maintenance cost of the radio frequency receiving circuit 100 can be effectively reduced, and the gain control efficiency is high.
In one embodiment, the controllable gain circuit 174 includes an adjustable gain amplifier or an adjustable power attenuator. It is understood that, in the present embodiment, the power adjustment of the received signal output by the low noise amplifier 16 can be directly implemented by using an adjustable gain amplifier or an adjustable power attenuator that is known in the art. The adjustable gain amplifier or the adjustable power attenuator is widely applied and highly reliable in the field, and can effectively improve the reliability of the radio frequency receiving circuit 100, thereby achieving the power adjustment of small-amplitude signals, better reducing the application cost and improving the performance of the receiver.
In one embodiment, a receiver is also provided, which includes the above-mentioned radio frequency receiving circuit 100.
It can be understood that, for the specific explanation of the rf receiving circuit 100 in this embodiment, reference may be made to the corresponding explanation in the above embodiments of the rf receiving circuit 100, and details are not repeated here. It should be noted that, as will be understood by those skilled in the art, the rf receiving circuit 100 is a component of a receiver, and may actually include other components, such as, but not limited to, a filter or an added power amplifier, which may be determined according to a specific type of the receiver in an actual application, and is not described in detail in this specification.
In the receiver, the radio frequency receiving circuit 100 is applied, and the base station antenna 101 receives a signal transmitted from a terminal in the vicinity, and then inputs the received signal to the radio frequency receiving circuit 100 through the duplexer 12. When the received signal contains a large-amplitude common-frequency large signal, the integrated amplitude limiter 14 in the radio frequency receiving circuit 100 limits the amplitude of the common-frequency large signal, so that the signal amplitude of the common-frequency large signal is lower than the saturation threshold of the low noise amplifier 16 after the amplitude of the common-frequency large signal is limited. Therefore, when receiving a common-frequency large signal sent by the terminal, the integrated amplitude limiter 14 limits the amplitude, which can effectively avoid causing the saturation of the low noise amplifier 16, thereby achieving the effect of protecting the low noise amplifier 16 and avoiding causing the overflow of the ADC (analog-to-digital converter) of the rear-stage transceiver unit 19. Meanwhile, the insertion loss introduced by the integrated amplitude limiter 14 is small, and the integrated amplitude limiter 14 does not limit the small-amplitude signal, so that the useful signal in the small-amplitude signal in the received signal is not affected, and the purpose of avoiding the performance damage of the receiver is achieved.
Referring to fig. 6, in an embodiment, a base station 200 is further provided, which includes the base station antenna 101 and the above-mentioned receiver.
It can be understood that, for the explanation of the base station antenna 101 and the receiver in this embodiment, the same principle can be understood by referring to the specific explanation of the base station antenna 101 and the receiver in the above corresponding embodiments, and repeated descriptions are not repeated in this embodiment and the subsequent embodiments.
Specifically, in an actual application scenario, the distance between the terminal 301 and the base station 200 is short, and a communication system in which the terminal 301 and the base station 200 coexist is formed. When the terminal 301 and the base station 200 operate simultaneously, the same-frequency large signal may cause interference to the radio frequency link of the receiver of the conventional base station, so that the link device is damaged. By applying the new receiver, the integrated amplitude limiter 14 is connected between the duplexer 12 and the low noise amplifier 16, so that when the received signal is mainly a common-frequency large signal, the common-frequency large signal with a large signal amplitude is limited by the integrated amplitude limiter 14, the signal amplitude of the common-frequency large signal is limited to be below the saturation threshold of the low noise amplifier 16, and the low noise amplifier 16 is prevented from being saturated when the received signal enters the low noise amplifier 16 for amplification.
Received signals in different time periods can be different, and only the integrated amplitude limiter 14 needs to limit amplitude of common-frequency large signals through selection of the integrated amplitude limiter 14, and when small-amplitude signals are input, the integrated amplitude limiter 14 does not limit the small-amplitude signals, so that useful signals contained in the small-amplitude signals cannot be influenced.
By applying the new receiver, the base station 200 can effectively avoid saturation of the low noise amplifier 16 by limiting the amplitude of the integrated amplitude limiter 14 when receiving a common-frequency large signal sent by the terminal 301, thereby achieving the effect of protecting the low noise amplifier 16 and avoiding overflow of an ADC (analog-to-digital converter) of the post-stage transceiver unit 19. Meanwhile, the insertion loss introduced by the integrated amplitude limiter 14 is small, and the integrated amplitude limiter 14 does not limit the small-amplitude signal, so that the useful signal in the small-amplitude signal in the received signal is not affected, and the purpose of avoiding the performance damage of the receiver is achieved.
In one embodiment, base station 200 is an NB-IOT base station. It can be understood that, in this embodiment, the base station 200 to which the new receiver is applied may specifically be an NB-IOT (also called narrowband internet of things) base station in the art, so that the problems of signal interference of uplink communication between each terminal 301 and the NB-IOT base station in the NB-IOT system and damage to a radio frequency link of the receiver can be better solved, protection of a hardware current of the receiver is realized, meanwhile, performance of the receiver is prevented from being damaged, and service quality of the NB-IOT system is better improved.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above examples only show some embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A radio frequency receiving circuit is characterized by comprising a duplexer, an integrated amplitude limiter, a low-noise amplifier, a band-pass filter and a transceiving unit;
the common port of the duplexer is used for electrically connecting a base station antenna, and the duplexer, the integrated amplitude limiter, the low-noise amplifier, the band-pass filter and the receiving and transmitting unit are sequentially cascaded;
the integrated amplitude limiter is used for carrying out amplitude limiting on common-frequency large signals in the received signals output by the duplexer; and the signal amplitude of the amplitude-limited common-frequency large signal is lower than the saturation threshold of the low-noise amplifier.
2. The radio frequency receiving circuit according to claim 1, further comprising an adjustable gain control unit, wherein the low noise amplifier is connected to the band pass filter through the adjustable gain control unit;
the adjustable gain control unit is used for carrying out gain adjustment on a small-amplitude signal in the received signals output by the low-noise amplifier; and the power of the small-amplitude signal after the gain adjustment is lower than an ADC overflow threshold of the transceiving unit.
3. The radio frequency receiving circuit according to claim 2, wherein the adjustable gain control unit comprises a controller and a controllable gain circuit, the low noise amplifier being connected to the band pass filter through the controllable gain circuit;
the control output end of the controller is electrically connected with the gain control end of the controllable gain circuit, the power supply end of the controller is used for being electrically connected with a power supply, and the controller is used for adjusting the output gain of the controllable gain circuit;
the controllable gain circuit is used for detecting the power of the small-amplitude signal output by the low-noise amplifier, outputting the power to the controller, and adjusting the power of the small-amplitude signal.
4. The radio frequency receiving circuit according to claim 2, wherein the adjustable gain control unit comprises a detection circuit, a controller and a controllable gain circuit;
the detection circuit is cascaded with the controllable gain circuit, and the low-noise amplifier is connected to the band-pass filter through the detection circuit and the controllable gain circuit;
the power supply end of the controller is used for being electrically connected with a power supply, the detection input end of the controller is electrically connected with the detection output end of the detection circuit, and the control output end of the controller is electrically connected with the gain control end of the controllable gain circuit;
the detection circuit is used for detecting the power of the small-amplitude signal output by the low-noise amplifier and outputting the power to the controller, the controller is used for adjusting the output gain of the controllable gain circuit, and the controllable gain circuit is used for adjusting the power of the small-amplitude signal.
5. The radio frequency receiving circuit according to claim 3 or 4, wherein the controller comprises an FPGA chip, a CPLD device or a single chip microcomputer.
6. The radio frequency receive circuit of claim 4, wherein the controllable gain circuit comprises an adjustable gain amplifier or an adjustable power attenuator.
7. The radio frequency receiving circuit according to claim 1, wherein the transceiver unit is further configured to perform gain adjustment on a small-amplitude signal in the received signals output by the band-pass filter; and the power of the small-amplitude signal after the gain adjustment is lower than an ADC overflow threshold of the transceiving unit.
8. A receiver comprising the radio frequency receiving circuit of any of claims 1 to 7.
9. A base station, characterized in that it comprises a base station antenna and a receiver according to claim 8.
10. The base station of claim 9, wherein the base station is an NB-IOT base station.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911424135.XA CN111162808A (en) | 2019-12-31 | 2019-12-31 | Radio frequency receiving circuit, receiver and base station |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911424135.XA CN111162808A (en) | 2019-12-31 | 2019-12-31 | Radio frequency receiving circuit, receiver and base station |
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| CN111162808A true CN111162808A (en) | 2020-05-15 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201911424135.XA Pending CN111162808A (en) | 2019-12-31 | 2019-12-31 | Radio frequency receiving circuit, receiver and base station |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111654307A (en) * | 2020-05-27 | 2020-09-11 | 珠海泰芯半导体有限公司 | Radio frequency front end protection method |
| CN113014282A (en) * | 2021-02-18 | 2021-06-22 | 深圳捷扬微电子有限公司 | Automatic gain control method, device, receiver and ultra-wideband communication system |
-
2019
- 2019-12-31 CN CN201911424135.XA patent/CN111162808A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111654307A (en) * | 2020-05-27 | 2020-09-11 | 珠海泰芯半导体有限公司 | Radio frequency front end protection method |
| CN111654307B (en) * | 2020-05-27 | 2022-03-08 | 珠海泰芯半导体有限公司 | Radio frequency front end protection method |
| CN113014282A (en) * | 2021-02-18 | 2021-06-22 | 深圳捷扬微电子有限公司 | Automatic gain control method, device, receiver and ultra-wideband communication system |
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