CN113890561B - Electronic equipment and radio frequency circuit thereof - Google Patents
Electronic equipment and radio frequency circuit thereof Download PDFInfo
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- CN113890561B CN113890561B CN202111364754.1A CN202111364754A CN113890561B CN 113890561 B CN113890561 B CN 113890561B CN 202111364754 A CN202111364754 A CN 202111364754A CN 113890561 B CN113890561 B CN 113890561B
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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
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/40—Circuits
- H04B1/401—Circuits for selecting or indicating operating mode
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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
- H04B1/005—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 adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
- H04B1/0053—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 adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges with common antenna for more than one band
- H04B1/0057—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 adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges with common antenna for more than one band using diplexing or multiplexing filters for selecting the desired band
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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
- H04B1/02—Transmitters
- H04B1/04—Circuits
- H04B1/0458—Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages
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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
- H04B1/02—Transmitters
- H04B1/04—Circuits
- H04B1/0475—Circuits with means for limiting noise, interference or distortion
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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
- 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
- H04B1/18—Input circuits, e.g. for coupling to an antenna or a transmission line
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Abstract
The application discloses electronic equipment and radio frequency circuit thereof, including controller, filter circuit, radio frequency transceiver, power amplifier and antenna matching circuit, through being connected filter circuit's input and the output of controller for receiving baseband signal and filtering baseband signal, filter circuit's output is connected with radio frequency transceiver's input, is used for sending the baseband signal after filtering to radio frequency transceiver and modulates, and power amplifier's input and output are connected with radio frequency transceiver's output and antenna matching circuit's input respectively, are used for amplifying the power of baseband signal after filtering, and carry out antenna matching. Therefore, the radio frequency circuit provided by the application can avoid the problem that the signal leaks in the adjacent channel because part of the amplified signal is out of the range of the required bandwidth by filtering the baseband signal before modulating the baseband signal into the high-frequency signal.
Description
Technical Field
The present disclosure relates to the field of radio frequency technologies, and in particular, to an electronic device and a radio frequency circuit thereof.
Background
Modern communication technologies are becoming more and more diverse, such as global positioning system (Global Positioning System, GPS), near field communication (Near Field Communication, NFC), etc., and the same portable wearable device often needs to integrate multiple communication circuits with multiple radio frequency modules. However, in wireless communication, there is a strict requirement on interference of adjacent channels, that is, the frequency band of the modulated signal is strictly controlled in its own channel, and leakage into adjacent channels is not allowed. The current technology is to modulate a baseband signal by sending the baseband signal to a radio frequency transceiver, and then perform antenna matching after modulating the baseband signal into a high-frequency signal.
Since the signal is amplified after being modulated into a high frequency signal, this easily results in a part of the amplified signal being out of the required bandwidth range, causing leakage of the signal in adjacent channels.
In view of the above, designing a radio frequency circuit for preventing signal leakage is a problem to be solved by those skilled in the art.
Disclosure of Invention
The application aims to provide electronic equipment and a radio frequency circuit thereof, which are mainly applied to wearable electronic equipment such as mobile phones, smart watches and other equipment.
To solve the problem that a signal is amplified after being modulated into a high-frequency signal, the amplified signal is easily out of a desired range, and the signal leaks in an adjacent channel.
In order to solve the above technical problems, the present application provides a radio frequency circuit, which includes a controller 10, a filter circuit 11, a radio frequency transceiver 12, a power amplifier 13, and an antenna matching circuit 14;
wherein an input end of the filter circuit 11 is connected with an output end of the controller 10, and is used for receiving a baseband signal and filtering the baseband signal;
the output end of the filter circuit 11 is connected with the input end of the radio frequency transceiver 12, and is used for sending the filtered baseband signal to the radio frequency transceiver 12 for modulation;
the input end and the output end of the power amplifier 13 are respectively connected with the output end of the radio frequency transceiver 12 and the input end of the antenna matching circuit 14, and are used for amplifying the power of the filtered baseband signal and performing antenna matching.
Preferably, a signal detection circuit 15 is also included,
the input end of the signal detection circuit 15 is connected with the output end of the power amplifier 13, and is used for judging whether the parameters of the amplified signal meet preset conditions or not; the first output end of the signal detection circuit 15 is connected with the input end of the antenna matching circuit 14, and is used for sending the signal meeting the preset condition to the antenna matching circuit 14 for antenna matching; a second output terminal of the signal detection circuit 15 is connected to an input terminal of the filter circuit 11, and is configured to return a signal that does not satisfy the preset condition to the filter circuit 11.
Preferably, the signal detection circuit 15 includes a mixer, a local oscillator, an intermediate frequency filter, an amplifier and a detector;
the first input end of the mixer is used as the input end of the signal detection circuit 15 and is used for receiving the signal with the amplified frequency of the power amplifier 13, and the second input end of the mixer is connected with the local oscillator and is used for receiving the local oscillator signal and mixing with the signal with the amplified frequency to obtain a mixed signal; the input end of the intermediate frequency filter is connected with the output end of the mixer and is used for filtering the mixed signals to obtain intermediate frequency signals, the input end of the amplifier is connected with the output end of the intermediate frequency filter and is used for amplifying the intermediate frequency signals, and the input end of the detector is connected with the output end of the amplifier and is used for receiving amplified signals and measuring the maximum frequency and the minimum frequency of the amplified signals.
Preferably, the preset condition is that the difference between the maximum frequency and the minimum frequency of the amplified signal is equal to a threshold value.
Preferably, the filter circuit 11 includes a plurality of switches and a plurality of filters, the switches and the filters being in one-to-one correspondence;
one of the switches is connected with the corresponding filter and is used for forming a filtering channel; and each filtering channel is connected in parallel and is used for switching the corresponding switch to replace the filter for filtering again when the amplified baseband signal does not meet the preset condition.
Preferably, the plurality of switches are single-pole multi-throw switches, wherein the moving ends of the single-pole multi-throw switches are respectively in one-to-one correspondence with the filters.
Preferably, only one of the filters is active at a time.
Preferably, the number of filters is at least 3.
In order to solve the technical problem, the application further provides electronic equipment comprising the radio frequency circuit.
Preferably, the electronic device is a wearable device.
The radio frequency circuit that this application provided includes controller, filter circuit, radio frequency transceiver, power amplifier, antenna matching circuit, through being connected filter circuit's input with the output of controller for receive baseband signal and filter baseband signal, filter circuit's output is connected with radio frequency transceiver's input, is used for sending the baseband signal after filtering to radio frequency transceiver and modulates, and power amplifier's input and output are connected with radio frequency transceiver's output and antenna matching circuit's input respectively, are used for amplifying the power of baseband signal after filtering, carry out antenna matching. Therefore, the radio frequency circuit provided by the application can avoid the problem that the signal leaks in the adjacent channel because part of the amplified signal is out of the range of the required bandwidth by filtering the baseband signal before modulating the baseband signal into the high-frequency signal.
On the basis, the application also provides electronic equipment which comprises the radio frequency circuit, and the effect is the same as that of the radio frequency circuit.
Drawings
For a clearer description of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described, it being apparent that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of a radio frequency circuit according to an embodiment of the present application;
fig. 2 is a schematic structural diagram of another radio frequency circuit according to an embodiment of the present disclosure;
fig. 3 is a schematic structural diagram of a signal detection circuit according to an embodiment of the present application;
fig. 4 is a schematic structural diagram of a filter circuit according to an embodiment of the present application.
Wherein 10 is a controller, 11 is a filter circuit, 12 is a radio frequency transceiver, 13 is a power amplifier, 14 is an antenna matching circuit, and 15 is a signal detection circuit.
Detailed Description
The following description of the technical solutions in the embodiments of the present application will be made clearly and completely with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments herein without making any inventive effort are intended to fall within the scope of the present application.
The core of the application is to provide an electronic device and a radio frequency circuit thereof, which are used for filtering a baseband signal before the baseband signal is modulated into a high-frequency signal by a radio frequency transceiver, so as to avoid the problem that a part of the amplified signal is out of a required bandwidth range, and the leakage of the signal in an adjacent channel is caused. In order to provide a better understanding of the present application, those skilled in the art will now make further details of the present application with reference to the drawings and detailed description.
Fig. 1 is a schematic structural diagram of a radio frequency circuit according to an embodiment of the present application, and the structure of the radio frequency circuit shown in fig. 1 is described below.
It will be appreciated that modern communication technologies are becoming more and more diverse, such as global positioning system GPS, NFC, etc., and that the same portable wearable device often requires integration of multiple communication circuits, with multiple radio frequency modules. However, in wireless communication, there is a strict requirement on interference of adjacent channels, that is, the frequency band of a modulated signal is strictly controlled in its own channel, and leakage into an adjacent channel is not allowed. Since the signal is amplified after being modulated into a high frequency signal, this easily results in a part of the amplified signal being out of the required bandwidth range, causing leakage of the signal in adjacent channels. If a narrow-band filter is added after the power amplifier, but the carrier frequency introduced during modulation exceeds the bandwidth of the demodulated wave, the narrow-band filter needs to have a higher Q value, which is not beneficial to cost reduction, and in addition, the filter with a high Q value has steeper amplitude frequency and phase frequency characteristics, which is easy to distort signals and causes waste in power consumption. In this embodiment, a filter circuit is added before the rf transceiver, as shown in fig. 1, the rf circuit includes a controller 10, a filter circuit 11, an rf transceiver 12, a power amplifier 13 and an antenna matching circuit 14, where an input end of the filter circuit 11 is connected to an output end of the controller 10, and is used to receive a baseband signal and filter the baseband signal, an output end of the filter circuit 11 is connected to an input end of the rf transceiver 12, and is used to send the filtered baseband signal to the rf transceiver 12 for modulation, and an input end and an output end of the power amplifier 13 are respectively connected to an output end of the rf transceiver 12 and an input end of the antenna matching circuit 14, and are used to amplify the power of the filtered baseband signal and perform antenna matching.
It should be noted that the filtering module 11 is disposed between the controller 10 and the radio frequency transceiver 12, and filters unwanted signals in the baseband signal of the controller 10, so that the filtering module 11 adopts a low-pass filtering manner. Low pass filtering allows a low frequency signal to pass from the input to the output port with little attenuation, and when the signal exceeds its cutoff frequency, the attenuation of the signal increases dramatically, resulting in a decrease in the amplitude of the high frequency signal at the output port. The specific structure of the filter circuit 11 is not limited, the filter circuit 11 may be a combination of a filter and a resistor, or a combination of a plurality of filters and a resistor to form the filter circuit 11, the specific structure is not limited only by being capable of filtering the baseband signal transmitted by the controller 10, in addition, the controller 10 may be a central processing unit (central processing unit, CPU or a micro control unit (Microcontroller Unit; MCU)), in addition, the radio frequency transceiver 12 is a device for implementing signal transmission by using radio frequency, and includes steps of signal processing, modulation demodulation, amplification, transmission, etc. in the process of implementing signal receiving and transmitting, the radio frequency transceiver 12 receives the baseband signal filtered by the filter circuit 11 and amplifies the baseband signal into a high frequency signal, and the specific model of the radio frequency transceiver 12 is not limited only by being capable of modulating the baseband signal into a high frequency signal.
In addition, in rf circuits, to achieve maximum power transfer, the load impedance and the source impedance must be matched, typically with a passive network, known as a matching network, interposed therebetween. Its effects are, besides reducing power loss, reducing noise interference, increasing power capacity, improving spectral linearity, etc. It is generally recognized that the purpose of a matching network is to achieve impedance transformation, transforming a given impedance value into other impedance values within a frequency band. The antenna matching in this design serves to match the impedance of the power amplifier 13 and the antenna, achieving the highest efficiency of signal transfer.
The radio frequency circuit provided by the embodiment comprises a controller, a filter circuit, a radio frequency transceiver, a power amplifier and an antenna matching circuit, wherein the input end of the filter circuit is connected with the output end of the controller and is used for receiving baseband signals and filtering the baseband signals, the output end of the filter circuit is connected with the input end of the radio frequency transceiver and is used for transmitting the filtered baseband signals to the radio frequency transceiver for modulation, and the input end and the output end of the power amplifier are respectively connected with the output end of the radio frequency transceiver and the input end of the antenna matching circuit and are used for amplifying the power of the filtered baseband signals and performing antenna matching. Therefore, the radio frequency circuit provided by the application filters the baseband signal before modulating the baseband signal into the high-frequency signal, so that the problem that the signal leaks in an adjacent channel because part of the amplified signal is out of the required bandwidth range is avoided.
In a specific embodiment, the baseband signal is filtered before being modulated into the high-frequency signal, so that the problem that the amplified signal leaks in the adjacent channel due to the fact that a part of the amplified signal is out of the required bandwidth range is avoided, but the filtered signal may be different from the required bandwidth and may be too narrow or too wide, so that fig. 2 is a schematic structural diagram of another radio frequency circuit provided in the embodiment of the present application, and as shown in fig. 2, the signal detection circuit 15 is further included on the basis of the embodiment.
The input end of the signal detection circuit 15 is connected with the output end of the power amplifier 13, and is used for judging whether the parameters of the amplified signal meet preset conditions or not; the first output end of the signal detection circuit 15 is connected with the input end of the antenna matching circuit 14, and is used for sending a signal meeting a preset condition to the antenna matching circuit 14 for antenna matching; a second output terminal of the signal detection circuit 15 is connected to an input terminal of the filter circuit 11 for returning a signal not satisfying a preset condition to the filter circuit 11.
In this embodiment, the signal detection circuit 15 receives the high-frequency signal of the power amplifier 13, measures the parameter of the high-frequency signal, sends a signal satisfying the preset condition to the antenna matching circuit 14 for antenna matching, and sends a signal not satisfying the preset condition to the input terminal of the filter circuit 11. In a specific embodiment, for a high-frequency signal with a continuously changing frequency, the period of the signal can be calculated by calculating the number of rising edges and falling edges, so as to obtain the parameter of the signal.
It should be noted that the specific signal parameters are not limited in this embodiment, the signal can be judged by using the specific signal parameters, in addition, when the signal detection circuit 15 detects that the current signal does not meet the preset condition, the signal is returned to the filtering circuit 11 for filtering again, and the filtering frequency of the second filtering is different from that of the first filtering, so that the corresponding adjustment can be made on whether the current signal needs to be increased in bandwidth or narrowed in bandwidth, and when the current signal meets the preset condition, the signal is sent to the antenna matching circuit 14 for antenna matching.
Therefore, the signal detection circuit provided in this embodiment can determine whether the amplified signal parameters meet the preset conditions by connecting the input end of the signal detection circuit with the power amplifier, and then connect the first output end and the second output end of the signal detector circuit with the input end of the antenna matching circuit and the input end of the filter circuit respectively, if the current signal is detected to meet the preset conditions, the signal is sent to the antenna matching circuit for antenna matching, and if the current signal is detected to not meet the preset conditions, the signal is returned to the filter circuit for secondary filtering, so that the accuracy in antenna matching is effectively improved, the occurrence of signal mismatch is reduced, and the working efficiency of the whole circuit is improved.
On the basis of the above embodiment, the specific structure of the signal detection circuit 15 is defined, and the design of the signal detection circuit is similar to the principle of a spectrum analyzer, and the spectrum analyzer adopts a frequency scanning superheterodyne operation mode. First, the mixer mixes the received signal with the local oscillation signal, and when the mixed signal is equal to the intermediate frequency, the signal can be amplified by the intermediate frequency amplifier and peak detection is performed. The detected signal is amplified by a video amplifier and then displayed. When the frequency of the local oscillation circuit changes with time, the amplitude of the signal at different frequencies is recorded on the screen, and a signal frequency spectrum is obtained. In the design of the signal detection circuit, only the frequency value with the maximum and minimum signal is needed to be obtained. Since the spectrum of the signal does not need to be obtained, no video filter is needed. Because the signal transmitted to the signal detector by the power amplifier is clean and has no noise, a radio frequency attenuator and a low-pass filter at the front end are not needed. Since the mixer is a nonlinear device whose output contains, in addition to the two original signals, their harmonics and the sum and difference signals of the original signals and their harmonics, an intermediate frequency filter is necessary. The circuit therefore requires a mixer U1, a local oscillator U2, an intermediate frequency filter U3, an amplifier U4 and a detector U5. Fig. 3 is a schematic structural diagram of a signal detection circuit according to an embodiment of the present application, and as shown in fig. 3, the signal detection circuit 15 includes a mixer U1, a local oscillator U2, an intermediate frequency filter U3, an amplifier U4, and a detector U5. It will be appreciated that in the conventional signal detection circuit 15, a video filter, a radio frequency attenuator, a low pass filter, etc. are also required, but in the embodiment of the present application, it is only required to determine whether the current signal meets the preset condition according to the parameters of the signal, so that the spectrum of the signal is not required to be obtained, so that the video filter is not required, and the power amplifier 13 amplifies the power of the signal and then sends the amplified signal to the signal detection circuit 15, so that the radio frequency attenuator and the low pass filter are not required.
The specific structure of the signal detection circuit 15 is that a first input end of the mixer U1 is used as an input end of the signal detection circuit 15 and is used for receiving a signal with the amplified frequency of the power amplifier 13, and a second input end of the mixer U1 is connected with the local oscillator U2 and is used for receiving a local oscillator signal and mixing with the signal with the amplified frequency to obtain a mixed signal; the input end of the intermediate frequency filter U3 is connected with the output end of the mixer U1 and used for filtering the mixed signals to obtain intermediate frequency signals, the input end of the amplifier U4 is connected with the output end of the intermediate frequency filter U3 and used for amplifying the intermediate frequency signals, and the input end of the detector U5 is connected with the output end of the amplifier U4 and used for receiving the amplified signals and measuring the maximum frequency and the minimum frequency of the amplified signals.
In addition, the signal detection circuit 15 is provided with a detector U5 for measuring parameters of the signal, and the detector U5 is provided with information such as frequency, period, bandwidth, etc. of the signal, so that the current signal can be judged according to the measured information.
The specific structure of the signal detection circuit and the connection mode thereof provided by the embodiment comprise a mixer, a local oscillator, an intermediate frequency filter, an amplifier and a detector. The signal detection circuit is specifically structured that a first input end of a mixer is used as an input end of the signal detection circuit and used for receiving signals with amplified frequencies of a power amplifier, and a second input end of the mixer is connected with a local oscillator and used for receiving local oscillator signals and mixing the local oscillator signals with the signals with amplified frequencies to obtain mixed signals; the input end of the intermediate frequency filter is connected with the output end of the mixer and is used for filtering the mixed signal to obtain an intermediate frequency signal, the input end of the amplifier is connected with the output end of the intermediate frequency filter and is used for amplifying the intermediate frequency signal, the input end of the detector is connected with the output end of the amplifier and is used for receiving the amplified signal and measuring the maximum frequency and the minimum frequency of the amplified signal, the parameter of the current signal is accurately measured, whether the current signal needs secondary filtering or not is detected through the parameter, the accuracy of the circuit is improved, and the possibility of transmitting the signal by mistake is reduced.
On the basis of the above embodiment, the preset condition is defined, wherein the preset condition is that the difference between the maximum frequency and the minimum frequency of the amplified signal is equal to the threshold value, so that the signal detection circuit 15 only needs to detect the frequency of the current signal, the frequency of the signal is measured by the detector U5, the maximum frequency and the minimum frequency are extracted from the frequency, and the difference is determined to be equal to the threshold value, and the threshold value is the bandwidth required when the signal has the transmitting antenna.
Therefore, the preset condition provided by the embodiment judges whether the signal meets the preset condition or not by calculating the difference value between the maximum frequency and the minimum frequency of the signal, and the preset condition has a simple calculation mode and easily obtained parameters, so that the calculation complexity is effectively reduced, and the working efficiency of the circuit is improved.
In the embodiment, when the signal of the preset condition is not satisfied, the signal is returned to the filter circuit 11 for the secondary filtering, and the range of the secondary filtering is different, so that the specific structure of the filter circuit 11 is defined. Fig. 4 is a schematic structural diagram of a filtering circuit provided in this embodiment of the present application, as shown in fig. 4, the filtering circuit 11 includes a plurality of switches and a plurality of filters, the switches and the filters are in one-to-one correspondence, and are connected with the corresponding filters through a switch to form a filtering channel, and all the filtering channels are connected in parallel with each other, when a signal that does not meet a preset condition is returned, a required filtering channel can be determined according to the bandwidth of the signal, and the signal is filtered again.
It should be noted that the kind of the switch is not limited in this embodiment, it may be a single-pole multi-throw switch or a common switch, so that the current in the circuit may be guaranteed to pass through, in addition, the range of the signal after filtering of each filter is different, specifically, the lower limit frequency of the first filter is f1L, the upper limit frequency is f1H, that is, the frequency range of the signal after filtering of the first filter is f 1L-f 1H, the lower limit frequency of the second filter is f2L, the upper limit frequency is f2H, that is, the frequency range of the signal after filtering of the first filter is f 2L-f 2H, and so on to the nth filter, in addition, the frequency range of each filter includes the received frequency point f0, the bandwidth range of the filter is gradually reduced, that is, B1> B2> B3> … > Bn, in addition, the specific number of the filters is not limited, and the design may be performed according to the requirements of different circuits.
In addition, when the circuit just starts to work, the filter with the middle filtering range starts to work first, when the parameter of the current signal is detected to be not in accordance with the preset condition, the signal is returned to the filtering circuit 11, whether the bandwidth required by the signal is wide or narrow is judged, and different filtering channels can be selected according to different bandwidths. It should be noted that, after the secondary filtering, the signal still cannot meet the preset condition, and the signal is filtered for three times until the parameter of the signal meets the preset condition.
Therefore, according to the filter circuit provided by the embodiment, the plurality of switches and the plurality of filters are arranged, the switches and the filters are in one-to-one correspondence, each switch and the corresponding filter form the filter channel, when the bandwidth of the signal is judged to be too wide or too narrow, the signal is re-filtered, the proper filter channel is selected according to the bandwidth, and when the secondary filtering can not meet the preset condition, the new filter channel is re-selected until the signal can meet the preset condition, so that the circuit effectively improves the accuracy of transmitting the signal to the antenna, and avoids false transmission and resource waste.
On the basis of the above embodiment, the specific types of the switches are defined, and as a preferred embodiment, the present embodiment adopts a single-pole multi-throw switch as an implementation manner of a plurality of switches, wherein the moving ends of the single-pole multi-throw switch are respectively in one-to-one correspondence with the filters.
The single-pole multi-throw switch provided by the embodiment can effectively reduce the use of switching devices, and the adoption of a plurality of switches can cause the problem of complicated circuit devices, and the adoption of the single-pole multi-throw switch effectively reduces the number of the switching devices.
In a specific embodiment, the simultaneous operation of multiple filters may cause confusion of signals, which is easy to aggravate the operation difficulty of the circuit, and considering this occurrence, the present embodiment defines the operation state of the filters, specifically:
when a signal enters the filter circuit 11, the filter in the middle of the filtering range is first entered, then the switch of the other filtering channel is in the off state, and the whole filter circuit 11 only works for the filtering channel.
Therefore, the working state of the filters is limited, only one filter is in the working state at the same time, the condition that a plurality of filters work simultaneously to cause signal confusion is effectively avoided, the accuracy of radio frequency circuit signals is improved, and the working efficiency of the circuit is improved.
Based on the above embodiment, the number of filters may be designed according to the requirements of different circuits, in a specific embodiment, less filters are used, which is easy to cause resource waste, so the number of filters, that is, the number of filtering channels, is limited, where the number of filters is the upper number, it is understood that when the circuit starts to work, the switch corresponding to the second filter is in a closed state, the other switches are in an open state, and when a signal that does not meet the preset condition is returned to the filtering circuit 11, a suitable filtering channel is selected according to the signal, and the signal is filtered for the second time.
Therefore, the number of the filters is limited to 3 in the embodiment, wherein the filter which works first is the filter with the middle filtering range, namely the second filter, when the bandwidth of the signal is judged to be narrow, the signal is sent to the first filter for secondary filtering, and when the bandwidth is wider, the signal is sent to the third filter for secondary filtering, therefore, the number of the filters is reduced, the waste of resources is also reduced, and the working efficiency of the circuit is improved.
Finally, the embodiment of the present application further provides an electronic device, which includes, in addition to the circuits such as the filter circuit 11, the signal detection circuit 15 mentioned in the foregoing embodiment, where the circuit is configured to obtain the parameter of the current signal, and detect whether the parameter of the current signal meets the preset condition. Since the above detailed descriptions of the circuits are provided, the detailed descriptions of the embodiments are omitted.
The electronic device provided in this embodiment includes a radio frequency circuit, where the radio frequency circuit includes a controller 10, a filter circuit 11, a radio frequency transceiver 12, a power amplifier 13, and an antenna matching circuit 14, where an input end of the filter circuit 11 is connected to an output end of the controller 10, and is used to receive baseband signals and filter the baseband signals, an output end of the filter circuit 11 is connected to an input end of the radio frequency transceiver 12, and is used to send the filtered baseband signals to the radio frequency transceiver 12 for modulation, and an input end and an output end of the power amplifier 13 are respectively connected to an output end of the radio frequency transceiver 12 and an input end of the antenna matching circuit 14, and is used to amplify and perform antenna matching on power of the filtered baseband signals. Therefore, the radio frequency circuit provided by the application can avoid the problem that the signal leaks in the adjacent channel because part of the amplified signal is out of the range of the required bandwidth by filtering the baseband signal before modulating the baseband signal into the high-frequency signal.
The radio frequency circuit provided by the present application is described in detail above. In the description, each embodiment is described in a progressive manner, and each embodiment is mainly described by the differences from other embodiments, so that the same similar parts among the embodiments are mutually referred. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant points refer to the description of the method section. It should be noted that it would be obvious to those skilled in the art that various improvements and modifications can be made to the present application without departing from the principles of the present application, and such improvements and modifications fall within the scope of the claims of the present application.
It should also be noted that in this specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
Claims (9)
1. A radio frequency circuit, comprising: a controller (10), a filter circuit (11), a radio frequency transceiver (12), a power amplifier (13), an antenna matching circuit (14) and a signal detection circuit (15);
the input end of the filter circuit (11) is connected with the output end of the controller (10) and is used for receiving baseband signals and filtering the baseband signals;
the output end of the filter circuit (11) is connected with the input end of the radio frequency transceiver (12) and is used for transmitting the filtered baseband signal to the radio frequency transceiver (12) for modulation;
the input end and the output end of the power amplifier (13) are respectively connected with the output end of the radio frequency transceiver (12) and the input end of the signal detection circuit (15) and are used for amplifying the power of the filtered baseband signal;
the input end of the signal detection circuit (15) is connected with the output end of the power amplifier (13) and is used for judging whether the parameters of the amplified signal meet preset conditions or not; the first output end of the signal detection circuit (15) is connected with the input end of the antenna matching circuit (14) and is used for sending a signal meeting the preset condition to the antenna matching circuit (14) for antenna matching; the second output end of the signal detection circuit (15) is connected with the input end of the filter circuit (11) and is used for returning a signal which does not meet the preset condition to the filter circuit (11);
when the signal detection circuit (15) detects that the current signal does not meet the preset condition, the signal is returned to the filtering circuit (11) for filtering again, and the filtering frequency of the second filtering is different from that of the first filtering.
2. The radio frequency circuit according to claim 1, wherein the signal detection circuit (15) comprises a mixer, a local oscillator, an intermediate frequency filter, an amplifier and a detector;
the first input end of the mixer is used as the input end of the signal detection circuit (15) and is used for receiving the signal amplified by the power amplifier (13), and the second input end of the mixer is connected with the local oscillator and is used for receiving the local oscillator signal and mixing with the signal amplified by the power to obtain a mixed signal; the input end of the intermediate frequency filter is connected with the output end of the mixer and is used for filtering the mixed signals to obtain intermediate frequency signals, the input end of the amplifier is connected with the output end of the intermediate frequency filter and is used for amplifying the intermediate frequency signals, and the input end of the detector is connected with the output end of the amplifier and is used for receiving amplified signals and measuring the maximum frequency and the minimum frequency of the amplified signals.
3. The radio frequency circuit of claim 2, wherein the predetermined condition is that a difference between a maximum frequency and a minimum frequency of the amplified signal is equal to a threshold value.
4. A radio frequency circuit according to any one of claims 1 to 3, characterized in that the filter circuit (11) comprises a plurality of switches and a plurality of filters, the switches and the filters being in one-to-one correspondence;
one of the switches is connected with the corresponding filter and is used for forming a filtering channel; and each filtering channel is connected in parallel and is used for switching the corresponding switch to replace the filter for filtering again when the amplified baseband signal does not meet the preset condition.
5. The radio frequency circuit of claim 4, wherein the plurality of switches are single pole, multi-throw switches, and wherein the moving ends of the single pole, multi-throw switches are in one-to-one correspondence with the filters, respectively.
6. The radio frequency circuit of claim 5, wherein only one of the filters is active at a time.
7. The radio frequency circuit of claim 6, wherein the number of filters is at least 3.
8. An electronic device comprising the radio frequency circuit of any one of claims 1 to 7.
9. The electronic device of claim 8, wherein the electronic device is a wearable device.
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| RU2018122759A (en) * | 2015-11-23 | 2019-12-26 | Анлотек Лимитед | TUNABLE FILTER |
| US10374852B1 (en) * | 2018-09-10 | 2019-08-06 | United States Of America As Represented By The Administrator Of Nasa | Ka-band modulator and transmitter |
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