Radio frequency front-end bidirectional amplifying circuit
All as the field of technology
The utility model relates to the field of communication technology, especially, relate to a two-way amplifier circuit of radio frequency front end.
All the above-mentioned background techniques
Currently, a Time Division Duplex (TDD) system is a Duplex mode of a communication system, and is used for separating a receiving channel and a transmitting channel (or uplink and downlink) in a mobile communication system. In a TDD mode mobile communication system, reception and transmission are performed in different time slots of the same frequency channel, i.e. carrier, with guaranteed time to separate the reception and transmission channels. In a time division duplex system, in order to solve the problem of long-distance transmission, it is a common practice to increase the transmission power of the system by adding an external radio frequency front-end bidirectional amplifying circuit.
Usually, the uplink and downlink rf links of the rf front-end bidirectional amplifying circuit share an rf port. If the isolation degree of the radio frequency port is not good, in some special occasions, for example, when the antenna has poor contact or an open circuit, the radio frequency port can form radio frequency signal reflection, and the reflected signal is amplified by the downlink radio frequency link, leaks to the input end of the uplink amplifier and is amplified by the uplink amplifier, so that the radio frequency front-end bidirectional amplifying circuit cannot work normally.
All kinds of practical novel contents
The utility model aims at providing a two-way amplifier circuit of radio frequency front end reduces the reflection signal and passes through the enlargies of downlink radio frequency link, leaks the probability to go upward amplifier's input.
For the purpose of the utility model, the utility model discloses a technical scheme as follows:
a radio frequency front end bidirectional amplifying circuit comprises an uplink radio frequency link, a downlink radio frequency link and an antenna; the signal input end of the uplink radio frequency link receives radio frequency signals, and the signal output end of the uplink radio frequency link is connected with an antenna; the signal input end of the downlink radio frequency link is connected with an antenna, and the signal output end of the downlink radio frequency link sends a radio frequency signal;
the radio frequency front-end bidirectional amplifying circuit further comprises a directional coupler, a detector, an amplifier, a voltage comparator and a monostable trigger; the directional coupler, the detector, the amplifier, the voltage comparator and the monostable trigger are sequentially connected; the directional coupler receives a radio frequency signal sent to a downlink radio frequency link by an antenna; one signal input end of the voltage comparator is connected with the signal output end of the amplifier, and the other signal input end of the voltage comparator receives a reference voltage; and the signal output end of the monostable trigger outputs a control signal to the uplink radio frequency link and the downlink radio frequency link to control the connection or disconnection of the uplink radio frequency link and the downlink radio frequency link.
Further, the radio frequency front end bidirectional amplifying circuit further comprises a filter; the filter is connected between the amplifier and the voltage comparator, the input end of the filter is connected with the output end of the amplifier, and the output end of the filter is connected with one signal input end of the voltage comparator.
As a specific implementation manner, the uplink radio frequency link includes a first radio frequency port, a radio frequency transmitting path and a second radio frequency port, which are connected in sequence, the downlink radio frequency link includes a second radio frequency port, a radio frequency receiving path and a first radio frequency port, which are connected in sequence, one port of the first radio frequency port transmits or receives a radio frequency signal, the other two ports are connected to a signal input end of the radio frequency transmitting path and a signal output end of the radio frequency receiving path, respectively, one port of the second radio frequency port is connected to an antenna, the other two ports are connected to a signal output end of the radio frequency transmitting path and a signal input end of the radio frequency receiving path, respectively, the monostable trigger outputs a control signal to the radio frequency transmitting path and the radio frequency receiving path to control the radio frequency transmitting path and the radio frequency receiving path to be turned on or off, and/or, the monostable trigger outputs control signals to the first radio frequency port and the second radio frequency port to control the connection or disconnection of the radio frequency transmitting channel and the radio frequency receiving channel.
As a specific implementation manner, the uplink radio frequency link includes a radio frequency transmission path and a second radio frequency port that are sequentially connected, the downlink radio frequency link includes a second radio frequency port and a radio frequency reception path that are sequentially connected, one port of the second radio frequency port is connected to the antenna, the other two ports are respectively connected to a signal output end of the radio frequency transmission path and a signal input end of the radio frequency reception path, the monostable flip-flop outputs a control signal to the radio frequency transmission path and the radio frequency reception path to control the radio frequency transmission path and the radio frequency reception path to be switched on or off, and/or the monostable flip-flop outputs a control signal to the second radio frequency port to control the radio frequency transmission path and the radio frequency reception path to be switched on or off.
As a specific implementation, the first rf port includes a first circulator or a first rf switch, and the second rf port includes a second circulator or a second rf switch.
Further, the isolation of the first circulator + the isolation of the second circulator > the gain of the radio frequency transmission path + the gain of the radio frequency reception path.
For the purpose of the utility model, the utility model discloses another kind of technical scheme who takes as follows:
a radio frequency front end bidirectional amplifying circuit comprises an uplink radio frequency link, a downlink radio frequency link and an antenna; the signal input end of the uplink radio frequency link receives radio frequency signals, and the signal output end of the uplink radio frequency link is connected with an antenna; the signal input end of the downlink radio frequency link is connected with an antenna, and the signal output end of the downlink radio frequency link sends a radio frequency signal;
the radio frequency front-end bidirectional amplifying circuit further comprises a directional coupler, a detector, an amplifier, a filter, a first voltage comparator, a second voltage comparator, a selector and a monostable trigger; a signal input end of the directional coupler receives a radio frequency signal sent to a downlink radio frequency link by an antenna, and a signal output end of the directional coupler is connected with a signal input end of the detector; the signal output end of the detector is connected with the signal input end of the amplifier, one signal input end of the selector and one signal input end of the first voltage comparator; the signal output end of the amplifier is connected with the other signal input end of the selector, and the output end of the selector is connected with the signal input end of the filter; the other signal input end of the first voltage comparator receives a first reference voltage, and the signal output end of the first voltage comparator is connected with the control signal input end of the selector; the signal output end of the filter is connected with one signal input end of a second voltage comparator, the other signal input end of the second voltage comparator receives a second reference voltage, and the output end of the second voltage comparator is connected with the signal input end of the monostable trigger; and the signal output end of the monostable trigger outputs a control signal to the uplink radio frequency link and the downlink radio frequency link to control the connection or disconnection of the uplink radio frequency link and the downlink radio frequency link.
Further, the radio frequency front end bidirectional amplifying circuit further comprises a filter; the filter is connected between the selector and the second voltage comparator, the input end of the filter is connected with the output end of the selector, and the output end of the filter is connected with one signal input end of the second voltage comparator.
As a specific implementation manner, the uplink radio frequency link includes a first radio frequency port, a radio frequency transmitting path and a second radio frequency port, which are connected in sequence, the downlink radio frequency link includes a second radio frequency port, a radio frequency receiving path and a first radio frequency port, which are connected in sequence, one port of the first radio frequency port transmits or receives a radio frequency signal, the other two ports are connected to a signal input end of the radio frequency transmitting path and a signal output end of the radio frequency receiving path, respectively, one port of the second radio frequency port is connected to an antenna, the other two ports are connected to a signal output end of the radio frequency transmitting path and a signal input end of the radio frequency receiving path, respectively, the monostable trigger outputs a control signal to the radio frequency transmitting path and the radio frequency receiving path to control the radio frequency transmitting path and the radio frequency receiving path to be turned on or off, and/or, the monostable trigger outputs control signals to the first radio frequency port and the second radio frequency port to control the connection or disconnection of the radio frequency transmitting channel and the radio frequency receiving channel.
As a specific implementation manner, the uplink radio frequency link includes a radio frequency transmission path and a second radio frequency port that are sequentially connected, the downlink radio frequency link includes a second radio frequency port and a radio frequency reception path that are sequentially connected, one port of the second radio frequency port is connected to the antenna, the other two ports are respectively connected to a signal output end of the radio frequency transmission path and a signal input end of the radio frequency reception path, the monostable flip-flop outputs a control signal to the radio frequency transmission path and the radio frequency reception path to control the radio frequency transmission path and the radio frequency reception path to be switched on or off, and/or the monostable flip-flop outputs a control signal to the second radio frequency port to control the radio frequency transmission path and the radio frequency reception path to be switched on or off.
As a specific implementation, the first rf port includes a first circulator or a first rf switch, and the second rf port includes a second circulator or a second rf switch.
Further, the isolation of the first circulator + the isolation of the second circulator > the gain of the RF transmitting path + the gain of the RF receiving path
The utility model discloses beneficial effect:
according to the above technical scheme, the utility model discloses a directional coupler can detect antenna's reflection signal, demodulate the reflection signal into voltage signal through the wave detector, amplify and filtering processing voltage signal by amplifier and wave filter in proper order again, voltage signal after will amplifying by voltage comparator compares with reference voltage, trigger monostable trigger output control signal, control uplink radio frequency link and downlink radio frequency link switch on or break off, reduce the amplification of reflection signal through downlink radio frequency link, leak the probability of the input of uplink amplifier, namely, reduce the inside probability that switches on of uplink radio frequency link and downlink radio frequency link, improve uplink radio frequency link and downlink radio frequency link's isolation. Meanwhile, the utility model discloses an amplifier enlargies the processing to voltage signal, is convenient for carry out the comparison to weak reflection signal, reduces because reflection signal is weak, voltage comparator output high level, the probability that control signal control uplink radio frequency link and the downlink radio frequency link of monostable trigger output switched on. Further, the utility model discloses a wave filter carries out filtering to voltage signal and handles. Furthermore, the utility model adopts the circulator as the radio frequency port, thus realizing the self-adaptive receiving and transmitting switching of the radio frequency front-end bidirectional amplifying circuit; meanwhile, a first circulator and a second circulator are respectively arranged at two ends of the radio frequency transmitting path and the radio frequency receiving path, so that the isolation degree of the uplink radio frequency link and the downlink radio frequency link is improved. Further, the utility model discloses an isolation that sets up the isolation of first circulator + second circulator > power amplifier's gain + low noise amplifier's gain, further improved the isolation of uplink radio frequency link and downlink radio frequency link, reduced the inside probability that switches on of uplink radio frequency link and downlink radio frequency link.
Description of the drawings
In order to more clearly illustrate the embodiments of the present invention, the drawings used in the embodiments will be briefly described below. The drawings in the following description are only examples of the present invention, and other drawings can be obtained by those skilled in the art without inventive efforts.
Fig. 1 is a block diagram of a radio frequency front end bidirectional amplifying circuit according to an embodiment of the present invention;
fig. 2 is a block diagram of a specific structure of a bidirectional rf front-end amplifier circuit according to an embodiment of the present invention;
fig. 3 is a block diagram of a radio frequency front end bidirectional amplifying circuit provided in the second embodiment of the present invention;
fig. 4 is a specific block diagram of a radio frequency front end bidirectional amplifying circuit provided in the second embodiment of the present invention;
fig. 5 is a block diagram of a radio frequency front end bidirectional amplifying circuit provided in the third embodiment of the present invention;
fig. 6 is another structural block diagram of the rf front-end bidirectional amplifying circuit according to the third embodiment of the present invention.
(specific embodiments) in all cases
The present invention will be described in detail with reference to the accompanying drawings.
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Example one
As shown in fig. 1, a radio frequency front-end bidirectional amplifying circuit includes an uplink radio frequency link, a downlink radio frequency link, an antenna, a directional coupler, a detector, an amplifier, a filter, a voltage comparator, and a monostable flip-flop; the signal input end of the uplink radio frequency link receives radio frequency signals, the signal output end of the uplink radio frequency link is connected with the signal input end of the antenna, and the amplified radio frequency signals are sent to the antenna; the signal input end of the downlink radio frequency link is connected with the signal output end of the antenna, the radio frequency signal output by the antenna is received, and the signal output end sends the amplified radio frequency signal; a signal input end of the directional coupler receives a radio frequency signal sent to a downlink radio frequency link by an antenna, and a signal output end of the directional coupler is connected with a signal input end of the detector; the signal output end of the detector is connected with the signal input end of the amplifier; the signal output end of the amplifier is connected with the signal input end of the filter; the signal output end of the filter is connected with one signal input end of the voltage comparator; the other signal input end of the voltage comparator receives a reference voltage, and the signal output end of the voltage comparator is connected with the signal input end of the monostable trigger; and the signal output end of the monostable trigger outputs a control signal to the uplink radio frequency link and the downlink radio frequency link to control the connection or disconnection of the uplink radio frequency link and the downlink radio frequency link.
In this embodiment, if the isolation between the uplink rf link and the downlink rf link is not good, in some special occasions, for example, under the condition that the antenna is in poor contact or open circuit, the directional coupler detects a reflected signal and sends the transmitted signal to the detector, the detector demodulates the reflected signal into a voltage signal, the amplifier and the filter sequentially amplify and filter the voltage signal, and then output the voltage signal to the voltage comparator, the voltage comparator compares the amplified voltage signal with a reference voltage, and the monostable trigger is triggered to output a control signal to control the connection or disconnection of the uplink rf link and the downlink rf link.
In this embodiment, when the amplified voltage signal is smaller than the reference voltage, the voltage comparator outputs a high level to trigger the control signal output by the monostable trigger to control the conduction of the uplink radio frequency link and the downlink radio frequency link, and the uplink radio frequency link and the downlink radio frequency link operate normally; when the amplified voltage signal is greater than the reference voltage, the voltage comparator outputs a control signal output by a low-level trigger monostable trigger to control the disconnection of the uplink radio frequency link and the downlink radio frequency link, and the reflected signal is prevented from being amplified by the downlink radio frequency link and leaking to the input end of the uplink amplifier.
In this embodiment, under the amplification effect of the amplifier, the small reflected signal detected by the directional coupler is amplified to a high voltage, so that the comparison of the small reflected signal is facilitated, and the probability that the voltage comparator outputs a high level and the control signal output by the monostable trigger controls the conduction of the uplink radio frequency link and the downlink radio frequency link due to the small reflected signal is reduced.
As shown in fig. 1, in the present embodiment, the uplink radio frequency link includes a first radio frequency port, a radio frequency transmission path, and a second radio frequency port, which are connected in sequence; the downlink radio frequency link comprises a second radio frequency port, a radio frequency receiving channel and a first radio frequency port which are connected in sequence; one port of the first radio frequency port transmits or receives radio frequency signals, and the other two ports are respectively connected with a signal input end of a radio frequency transmitting channel and a signal output end connected with a radio frequency receiving channel; one port of the second radio frequency port is connected with the antenna, and the other two ports are respectively connected with the signal output end of the radio frequency transmitting channel and the signal input end connected with the radio frequency receiving channel; the monostable trigger outputs control signals to the radio frequency transmitting path and the radio frequency receiving path to control the connection or disconnection of the radio frequency transmitting path and the radio frequency receiving path.
As shown in fig. 2, in the present embodiment, the first rf port includes a first circulator, the second rf port includes a second circulator, the rf transmit channel includes a power amplifier, and the rf receive channel includes a low noise amplifier; a first port of the first circulator receives/sends a radio frequency signal, a second port of the first circulator is connected with a signal input end of the power amplifier, and a signal output end of the power amplifier is connected with a first port of the second circulator; a second port of the second circulator is connected with a signal input end of the antenna, and a third port of the second circulator is connected with a signal input end of the low-noise amplifier; the signal output end of the low-noise amplifier is connected with the third port of the first circulator; after receiving radio frequency signals through the first port, the first circulator sends the radio frequency signals to the power amplifier through the second port for amplification, the radio frequency signal power amplifier sends the amplified radio frequency signals to the first port of the second circulator, and the second circulator sends the amplified radio frequency signals to the antenna through the second port; the second circulator receives the radio-frequency signal output by the antenna through the second port, the radio-frequency signal is sent to the low-noise amplifier through the third port to be amplified, and the low-noise amplifier sends the amplified radio-frequency signal to the third port of the first circulator; the enable signal input end of the power amplifier and the enable signal input end of the low noise amplifier receive the control signal output by the monostable trigger.
In this embodiment, when the amplified voltage signal is greater than the reference voltage, the voltage comparator triggers the control signal output by the monostable flip-flop to enable the power amplifier and the low noise amplifier to be disconnected, so as to prevent the reflected signal from leaking to the input end of the uplink amplifier through the amplification of the downlink radio frequency link; when the amplified voltage signal is smaller than the reference voltage, the voltage comparator triggers a control signal output by the monostable trigger to enable the power amplifier and the low noise amplifier to be conducted.
In this embodiment, since the circulator is a device that enables unidirectional ring transmission of electromagnetic waves, the radio frequency front-end bidirectional amplifying circuit adopts the circulator as a radio frequency port, thereby realizing adaptive transmit-receive switching of the radio frequency front-end bidirectional amplifying circuit (i.e., no control signal is needed to control the radio frequency front-end bidirectional amplifying circuit to switch transmission and reception); meanwhile, a first circulator and a second circulator are respectively arranged at two ends of the radio frequency transmitting path and the radio frequency receiving path, so that the isolation degree of the uplink radio frequency link and the downlink radio frequency link is improved.
In this embodiment, the isolation of the first circulator and the isolation of the second circulator are greater than the gain of the power amplifier and the gain of the low noise amplifier, so that the isolation between the uplink radio frequency link and the downlink radio frequency link is further improved, and the probability of internal conduction between the uplink radio frequency link and the downlink radio frequency link is reduced.
Example two
As shown in fig. 3 and 4, the present embodiment is different from the first embodiment in that: the monostable trigger does not output a control signal to the radio frequency transmitting channel and the radio frequency receiving channel, but sends the control signal to the first radio frequency port and the second radio frequency port to control the first radio frequency port and the second radio frequency port to be switched on or switched off.
In this embodiment, the first rf port includes a first rf switch, and the second rf port includes a second rf switch; the fixed end of the first radio frequency switch receives/sends radio frequency signals, and the two free ends are respectively connected with the signal input end of the power amplifier and the signal output end of the low noise amplifier; the fixed end of the second radio frequency switch is connected with the antenna, and the two free ends are respectively connected with the signal output end of the power amplifier and the signal input end of the low-noise amplifier; the switch control signal input end of the first radio frequency switch and the switch control signal input end of the low noise amplifier receive the control signal output by the monostable trigger.
In this embodiment, when the amplified voltage signal is greater than the reference voltage, the switch control signal output by the monostable flip-flop controls the first radio frequency switch and the second radio frequency switch to be switched off, so as to prevent the reflected signal from being amplified by the downlink radio frequency link and leaking to the input end of the uplink amplifier; when the amplified voltage signal is smaller than the reference voltage, the switch control signal output by the monostable trigger controls the first radio frequency switch and the second radio frequency switch to conduct the uplink radio frequency link or the downlink radio frequency link according to the requirement of transmitting or receiving signals.
EXAMPLE III
As shown in fig. 5 and 6, the present embodiment is different from the first embodiment or the second embodiment in that: a radio frequency front-end bidirectional amplifying circuit comprises an uplink radio frequency link, a downlink radio frequency link, an antenna, a directional coupler, a detector, an amplifier, a filter, a first voltage comparator, a second voltage comparator, a selector and a monostable trigger; a signal input end of the directional coupler receives a radio frequency signal sent to a downlink radio frequency link by an antenna, and a signal output end of the directional coupler is connected with a signal input end of the detector; the signal output end of the detector is connected with the signal input end of the amplifier, one signal input end of the selector and one signal input end of the first voltage comparator; the signal output end of the amplifier is connected with the other signal input end of the selector, and the output end of the selector is connected with the signal input end of the filter; the other signal input end of the first voltage comparator receives a first reference voltage, and the signal output end of the first voltage comparator is connected with the control signal input end of the selector; the signal output end of the filter is connected with one signal input end of a second voltage comparator, the other signal input end of the second voltage comparator receives a second reference voltage, and the output end of the second voltage comparator is connected with the signal input end of the monostable trigger; and the signal output end of the monostable trigger outputs a control signal to the uplink radio frequency link and the downlink radio frequency link to control the connection or disconnection of the uplink radio frequency link and the downlink radio frequency link.
In this embodiment, when the voltage signal output by the detector is less than the first reference voltage, the first voltage comparator controls the selector to select the voltage amplified by the amplifier to the second voltage comparator, and when the voltage signal output by the detector is greater than the first reference voltage, the first voltage comparator controls the selector to select the voltage directly output by the detector to the second voltage comparator, that is, when the reflected signal detected by the directional coupler is a small signal, the reflected signal is amplified and then compared with the second reference voltage, and when the reflected signal detected by the directional coupler is a large signal, the voltage output by the detector is directly compared with the second reference voltage, only the small signal is amplified, and the large signal can be directly compared without further amplification.
Example four
The difference between this embodiment and the first embodiment or the second embodiment or the third embodiment is that: the monostable trigger outputs control signals to the first radio frequency port, the radio frequency transmitting channel, the radio frequency receiving channel and the second radio frequency port at the same time, and controls the first radio frequency port, the radio frequency transmitting channel, the radio frequency receiving channel and the second radio frequency port to be switched on or switched off.
EXAMPLE five
The difference between this embodiment and the first embodiment or the second embodiment or the third embodiment is that: the radio frequency front end bidirectional amplifying circuit only comprises a second radio frequency port connected with the antenna and does not comprise the first radio frequency port, and the second radio frequency port controls the conduction of an uplink radio frequency link or a downlink radio frequency link, so that the switching of the transmission and the reception of the radio frequency front end bidirectional amplifying circuit is realized.
In this embodiment, the power amplifier operates only when the transmission channel is in the operating state, and the low noise amplifier operates only when the reception channel is in the operating state, which is convenient for reducing the power consumption of the wireless communication unit.
It is only above the preferred embodiment of the utility model, the utility model discloses a scope of protection does not only confine above-mentioned embodiment, the all belongings to the utility model discloses a technical scheme under the thinking all belongs to the utility model discloses a scope of protection. It should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.