CN113890561A - Electronic equipment and radio frequency circuit thereof - Google Patents

Abstract

The application discloses electronic equipment and radio frequency circuit thereof, including the controller, filter circuit, radio frequency transceiver, power amplifier and antenna matching circuit, through being connected filter circuit's input and the output of controller, be used for receiving baseband signal and filtering baseband signal, filter circuit's output and radio frequency transceiver's input are connected, be used for sending the baseband signal after filtering to radio frequency transceiver and modulate, and power amplifier's input and output are connected with radio frequency transceiver's output and antenna matching circuit's input respectively, be used for enlargiing the power of the baseband signal after filtering, and carry out 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 a part of the amplified signal is out of a required bandwidth range to cause signal leakage in an adjacent channel is avoided.

Description

Electronic equipment and radio frequency circuit thereof

Technical Field

The present application 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 diversified, such as Global Positioning System (GPS), 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 for interference of adjacent channels, that is, the frequency band of the modulation signal is strictly controlled in its own channel, and is not allowed to leak into adjacent channels. The current technology is to transmit baseband signals to a radio frequency transceiver for modulation, modulate the baseband signals into high frequency signals, and then perform antenna matching.

Since the signal is amplified after being modulated into a high frequency signal, it is easy to cause a part of the amplified signal to be out of the desired bandwidth range, resulting in leakage of the signal in an adjacent channel.

In view of the above-mentioned technologies, it is an urgent need for those skilled in the art to design a radio frequency circuit for preventing signal leakage.

Disclosure of Invention

The application aims to provide an electronic device and a radio frequency circuit thereof, which are mainly applied to wearable electronic devices, such as mobile phones, smart watches and other devices.

In order to solve the problem that signals are amplified after being modulated into high-frequency signals, the signals after being amplified are easily out of a required range, and the signals leak in adjacent channels.

In order to solve the above technical problem, the present application provides a radio frequency circuit, which includes acontroller 10, afilter circuit 11, aradio frequency transceiver 12, apower amplifier 13, and anantenna matching circuit 14;

the input end of thefilter circuit 11 is connected to the output end of thecontroller 10, and is configured to receive a baseband signal and filter the baseband signal;

the output end of thefilter circuit 11 is connected to the input end of theradio frequency transceiver 12, and is configured to send the filtered baseband signal to theradio frequency transceiver 12 for modulation;

the input end and the output end of thepower amplifier 13 are respectively connected to the output end of theradio frequency transceiver 12 and the input end of the antenna matchingcircuit 14, and are configured to amplify the power of the filtered baseband signal and perform antenna matching.

Preferably, asignal detection circuit 15 is also included,

the input end of thesignal detection circuit 15 is connected to the output end of thepower amplifier 13, and is configured to determine whether a parameter of the amplified signal satisfies a preset condition; a first output end of thesignal detection circuit 15 is connected to an input end of theantenna matching circuit 14, and is configured to send a signal meeting the preset condition to theantenna matching circuit 14 for antenna matching; a second output end of thesignal detection circuit 15 is connected to an input end of thefilter circuit 11, and is configured to return a signal that does not satisfy the preset condition to thefilter circuit 11.

Preferably, thesignal detection circuit 15 includes a mixer, a local oscillator, an intermediate frequency filter, an amplifier, and a detector;

a first input end of the mixer is used as an input end of thesignal detection circuit 15, and is configured to receive a signal of an amplified frequency of thepower amplifier 13, and a second input end of the mixer is connected to the local oscillator, and is configured to receive a local oscillation signal and mix the local oscillation signal with the signal of 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 used for filtering the mixing 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 used for amplifying the intermediate frequency signal, and the input end of the detector is connected with the output end of the amplifier and used for receiving the amplified signal and measuring the maximum frequency and the minimum frequency of the amplified signal.

Preferably, the preset condition is that a difference between a maximum frequency and a minimum frequency of the amplified signal is equal to a threshold.

Preferably, thefilter circuit 11 includes a plurality of switches and a plurality of filters, and the switches and the filters correspond to each other one by one;

one switch is connected with the corresponding filter to form a filtering channel; and the filtering channels are connected in parallel and used for switching the corresponding switch to replace the filter for secondary filtering when the amplified baseband signal does not accord with the preset condition.

Preferably, the switches are single-pole multi-throw switches, and the moving ends of the single-pole multi-throw switches respectively correspond to the filters one by one.

Preferably, only one of said filters is active at a time.

Preferably, the number of filters is at least 3.

In order to solve the above technical problem, the present application further provides an electronic device including the above radio frequency circuit.

Preferably, the electronic device is a wearable device.

The radio frequency circuit that this application provided includes the controller, filter circuit, the radio frequency transceiver, power amplifier, antenna matching circuit, be connected through the input with filter circuit and the output of controller, be used for receiving baseband signal and filtering baseband signal, filter circuit's output is connected with the input of radio frequency transceiver, be used for with baseband signal transmission after filtering to the radio frequency transceiver modulate, and power amplifier's input and output are connected with the output of radio frequency transceiver and antenna matching circuit's input respectively, be used for enlargiing the power of the baseband signal after filtering, and carry out 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 a part of the amplified signal is out of a required bandwidth range to cause signal leakage in an adjacent channel is avoided.

On the basis, the application also provides an electronic device, which comprises the radio frequency circuit mentioned above, and the effect is the same as above.

Drawings

In order to more clearly illustrate the embodiments of the present application, the drawings needed for the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings can be obtained by those skilled in the art without inventive effort.

Fig. 1 is a schematic structural diagram of a radio frequency circuit according to an embodiment of the present disclosure;

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 disclosure;

fig. 4 is a schematic structural diagram of a filter circuit according to an embodiment of the present disclosure.

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 technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without any creative effort belong to the protection 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 the signal leaks from an adjacent channel due to the fact that a part of the amplified signal is out of a required bandwidth range. In order that those skilled in the art will better understand the disclosure, the following detailed description will be given with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a radio frequency circuit according to an embodiment of the present application, and the following describes a structure of the radio frequency circuit shown in fig. 1.

It can be appreciated that modern communication technologies are more and more diversified, such as global positioning system GPS, 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 for interference of adjacent channels, that is, the frequency band of the modulated signal is strictly controlled in its own channel and is not allowed to leak to adjacent channels. Since the signal is amplified after being modulated into a high frequency signal, it is easy to cause a part of the amplified signal to be out of the desired bandwidth range, resulting in leakage of the signal in an adjacent channel. 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 favorable for reducing the cost, and in addition, the filter with a higher Q value has the characteristics of steeper amplitude frequency and phase frequency, which is easy to distort signals and cause waste in power consumption. In this embodiment, a filter circuit is added in front of the radio frequency transceiver, as shown in fig. 1, the radio frequency circuit includes acontroller 10, afilter circuit 11, aradio frequency transceiver 12, apower amplifier 13, and anantenna matching circuit 14, wherein an input end of thefilter circuit 11 is connected to an output end of thecontroller 10, and is configured to receive a baseband signal and filter the baseband signal, an output end of thefilter circuit 11 is connected to an input end of theradio frequency transceiver 12, and is configured to send the filtered baseband signal to theradio frequency transceiver 12 for modulation, and an input end and an output end of thepower amplifier 13 are respectively connected to an output end of theradio frequency transceiver 12 and an input end of theantenna matching circuit 14, and are configured to amplify power of the filtered baseband signal and perform antenna matching.

It should be noted that thefiltering module 11 is disposed between thecontroller 10 and therf transceiver 12, and filters unwanted signals in the baseband signal of thecontroller 10, so that thefiltering module 11 adopts a low-pass filtering manner. Low pass filtering allows low frequency signals to pass from the input to the output port with little attenuation, which increases dramatically when the signal exceeds its cutoff frequency, resulting in a decrease in the amplitude of the high frequency signal at the output port. In this embodiment, the specific structure of thefilter circuit 11 is not limited, thefilter circuit 11 may be a combination of a filter and a resistor, or a combination of multiple filters and resistors to form afilter circuit 11, and the specific structure is not limited, and only needs to be able to filter the baseband signal transmitted by thecontroller 10, in addition, thecontroller 10 may be a central processing Unit (CPU, or a Micro Controller Unit (MCU)), in addition, theradio frequency transceiver 12 is a device that uses radio frequency to realize signal transmission, and includes receiving and transmitting signals, and the processes of realizing receiving and transmitting include signal processing, modulation and demodulation, amplification, and transmission, where in this circuit, theradio frequency transceiver 12 receives the baseband signal filtered by thefilter circuit 11 and amplifies the baseband signal into a high frequency signal, and the specific model of theradio frequency transceiver 12 is not limited, only the baseband signal needs to be modulated into a high-frequency signal.

In addition, in radio frequency circuits, to achieve maximum power transfer, the load impedance and the source impedance must be matched, usually with a passive network, called a matching network, interposed between them. Its functions include 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 implement an impedance transformation that transforms a given impedance value to other impedance values within a frequency band. The antenna matching in this design serves to match the impedances of thepower 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 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 used for sending 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 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 a part of the amplified signal is out of a required bandwidth range to cause signal leakage in an adjacent channel is avoided.

In a specific embodiment, the baseband signal is filtered before being modulated into the high-frequency signal, although the problem that a part of the amplified signal is out of the required bandwidth range and causes signal leakage in an adjacent channel is avoided, the filtered signal may have a bandwidth different from the required bandwidth and may be generated in a too-narrow or too-wide situation, so 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, asignal detection circuit 15 is further included on the basis of the above embodiment.

The input end of thesignal detection circuit 15 is connected with the output end of thepower amplifier 13, and is used for judging whether the parameter of the amplified signal meets a preset condition; a first output end of thesignal detection circuit 15 is connected with an input end of theantenna matching circuit 14, and is used for sending a signal meeting a preset condition to theantenna matching circuit 14 for antenna matching; a second output of thesignal detection circuit 15 is connected to an input of thefilter circuit 11 for returning a signal that does not satisfy a preset condition to thefilter circuit 11.

In the present embodiment, thesignal detection circuit 15 receives the high-frequency signal from thepower amplifier 13, measures a parameter of the high-frequency signal, transmits a signal satisfying a preset condition to the antenna matchingcircuit 14 for antenna matching, and transmits a signal not satisfying the preset condition to the input terminal of thefilter circuit 11. In a specific embodiment, for a high-frequency signal with a constantly 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 parameters of the signal.

It should be noted that, in this embodiment, specific parameters of the signal are not limited, and the signal may be determined by using the signal, in addition, when thesignal detection circuit 15 detects that the current signal does not satisfy the preset condition, the signal is returned to thefilter circuit 11 for filtering again, and the second filtering is different from the first filtering in filter frequency, so that a corresponding adjustment may be made on whether the current signal needs to be adjusted to a higher bandwidth or a narrower bandwidth, and when the current signal satisfies the preset condition, the signal is sent to the antenna matchingcircuit 14 for antenna matching.

Therefore, the signal detection circuit provided by this embodiment can determine whether the parameter of the amplified signal satisfies the preset condition 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 it is detected that the current signal satisfies the preset condition, the signal is sent to the antenna matching circuit for antenna matching, and if it is detected that the current signal does not satisfy the preset condition, the signal is returned to the filter circuit for secondary filtering, so that the accuracy in antenna matching is effectively improved, the occurrence of the situation of signal mismatch is reduced, and the working efficiency of the whole circuit is improved.

On the basis of the above embodiments, the specific structure of thesignal detection circuit 15 is defined, 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 working mode. First, a mixer mixes a received signal with a local oscillation signal, and when the mixed signal is equal to an intermediate frequency, the signal may be amplified by an intermediate frequency amplifier and peak-detected. The detected signal is amplified by a video amplifier and then displayed. When the frequency of the local oscillation circuit changes along with time, the amplitude of the signal on different frequencies is recorded on the screen, and a signal frequency spectrum is obtained. In the design of the signal detection circuit, the frequency value of the maximum signal and the minimum signal only need to be obtained. Since the spectrum of the signal need not be available, no video filter is required. Because the signal transmitted to the signal detector by the power amplifier is cleaner and has no noise, a radio frequency attenuator and a low-pass filter at the front end are not needed. An intermediate frequency filter is necessary because the mixer is a non-linear 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. Therefore, what is needed in the circuit are 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 disclosure, and as shown in fig. 3, thesignal detection circuit 15 includes a mixer U1, a local oscillator U2, an intermediate frequency filter U3, an amplifier U4, and a detector U5. It can be understood that in the conventionalsignal detection circuit 15, devices such as a video filter, a radio frequency attenuator, and a low pass filter are also required, but in the embodiment of the present application, it is only necessary to determine whether the current signal satisfies the preset condition according to the parameter of the signal, and therefore, it is not necessary to obtain the frequency spectrum of the signal, so that the video filter is not used, and thepower amplifier 13 amplifies the power of the signal and then sends the amplified signal to thesignal detection circuit 15, so that the radio frequency attenuator and the low pass filter are not required.

The specific structure of thesignal detection circuit 15 is that a first input end of the mixer U1 is used as an input end of thesignal detection circuit 15 and is used for receiving a signal of an amplified frequency of thepower 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 oscillation signal and mixing the local oscillation signal with the signal of 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 signal to obtain an intermediate frequency signal, 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 signal, and the input end of the detector U5 is connected with the output end of the amplifier U4 and used for receiving the amplified signal and measuring the maximum frequency and the minimum frequency of the amplified signal.

In addition, the parameter for determining the preset condition is not limited, and may be a frequency or a bandwidth, and it is only required to determine whether the current signal meets the preset condition through the parameter, and in addition, in thesignal detection circuit 15, the detector U5 is used for measuring the parameter of the signal, and the information of the frequency, the period, the bandwidth, and the like of the signal can be obtained through the detector U5, so that the current signal can be determined according to the measured information.

The specific structure and connection mode of the signal detection circuit provided by this embodiment include a mixer, a local oscillator, an intermediate frequency filter, an amplifier, and a detector. The specific structure of the signal detection circuit is that a first input end of a frequency mixer is used as an input end of the signal detection circuit and is used for receiving signals of amplified frequency of a power amplifier, and a second input end of the frequency mixer is connected with a local oscillator and is used for receiving local oscillation signals and mixing the local oscillation signals with the signals of the amplified frequency to obtain mixed frequency signals; the input end of the intermediate frequency filter is connected with the output end of the mixer and used for filtering the mixing 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 used for amplifying the intermediate frequency signal, the input end of the detector is connected with the output end of the amplifier and 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 mistakenly sending the signal is reduced.

On the basis of the above embodiment, a preset condition is defined, in which the difference between the maximum frequency and the minimum frequency of the amplified signal is equal to the threshold, so that thesignal detection circuit 15 only needs to detect the frequency of the current signal, measure the frequency of the signal by the detector U5, extract the maximum frequency and the minimum frequency therefrom, and determine whether the difference is equal to the threshold, where the threshold is the bandwidth required when the signal has the transmitting antenna.

Therefore, according to the preset condition provided by the embodiment, whether the signal meets the preset condition is judged by calculating the difference value between the maximum frequency and the minimum frequency of the signal, the calculation mode of the preset condition is simple, the parameters are easy to obtain, the calculation complexity is effectively reduced, and the working efficiency of the circuit is improved.

In a specific embodiment, when the signal does not satisfy the preset condition, the signal is returned to thefilter circuit 11 for secondary filtering, and the ranges of the two filtering are different, so that the specific structure of thefilter circuit 11 is limited. Fig. 4 is a schematic structural diagram of a filter circuit according to an embodiment of the present application, as shown in fig. 4, afilter 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 to the corresponding filters through one switch to form a filter channel, and the filter channels are connected in parallel with each other.

It should be noted that the present embodiment does not limit the kind of the switch, and may be a single-pole multi-throw switch or a normal switch, so as to ensure that the current can pass through the circuit, and in addition, the range of the signal filtered by each filter is different, specifically, the lower limit frequency of the first filter is f1L, the upper limit frequency is f1H, namely, the frequency range of the signal filtered by the first filter is f 1L-f 1H, the lower limit frequency of the second filter is f2L, the upper limit frequency is f2H, i.e. the frequency range of the signal filtered by the first filter is f 2L-f 2H, and so on to the nth filter, and in addition, the frequency range of each filter contains the received frequency point f0, the bandwidth range of the filter gradually becomes smaller, namely B1> B2> B3> … > Bn, and the specific number of filters is not limited and may be designed according to the requirements of different circuits.

In addition, when the circuit starts to work, the filter with the middle filtering range starts to work first, and when the parameter of the current signal is detected to be not in accordance with the preset condition, the signal returns to thefiltering circuit 11, and then the bandwidth required by the signal is judged to be wide or narrow, so that different filtering channels can be selected according to different bandwidths. It should be noted that, after the second filtering, the signal still cannot satisfy the predetermined condition, the signal is filtered for three times until the parameter of the signal satisfies the predetermined condition.

Therefore, the filtering circuit provided by the embodiment has the advantages that 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 a filtering channel, when the bandwidth of the signal is judged to be too wide or too narrow, the signal is filtered again, the proper filtering channel is selected according to the bandwidth, when the secondary filtering still cannot meet the preset condition, a new filtering channel is selected again until the signal can meet the preset condition, therefore, the circuit effectively improves the accuracy of transmitting the signal to the antenna, and avoids the occurrence of mistaken sending and resource waste.

On the basis of the foregoing embodiments, specific types of switches are defined, and as a preferred embodiment, this embodiment adopts a single-pole multi-throw switch as an implementation manner of multiple switches, where moving ends of the single-pole multi-throw switch respectively correspond to filters one to one.

The single-pole multi-throw switch provided by the embodiment can effectively reduce the use of switching devices, the problem of complexity of circuit devices can be caused by adopting a plurality of switches, and the number of the switching devices is effectively reduced by adopting the single-pole multi-throw switch.

In a specific embodiment, the simultaneous operation of multiple filters may cause signal confusion, which may easily aggravate the operation difficulty of the circuit, and in consideration of this occurrence, this embodiment limits the operation state of the filter, specifically:

only one filter is in the operating condition at the same moment, it can be understood that, when a signal enters thefilter circuit 11, firstly, the filter in the middle of the filter range is entered, then, the switch of the other filter channel is in the off-state, thewhole filter circuit 11 only has the filter channel working, in addition, after the signal is detected to be out of conformity with the preset condition, when the signal is secondarily filtered, the switch in the selected filter channel is in the on-state, the filter starts to work, the switch of the other filter channel is in the off-state, the signal cannot enter, and therefore the chaotic condition of the signal is avoided.

Therefore, the working state of the filter is limited, only one filter is in the working state at the same time, the situation that a plurality of filters work simultaneously to cause signal confusion is effectively avoided, the accuracy of the radio frequency circuit signal is improved, and the working efficiency of the circuit is improved.

On the basis of the above embodiments, the number of filters may be designed according to the requirements of different circuits, and in a specific embodiment, fewer filters are used, which is easy to cause a situation of resource waste, so the number of filters, that is, the number of filter channels, is limited, where the number of filters is the last, it can be understood that when a circuit starts to operate, first the switch corresponding to the second filter is in a closed state, and the other switches are in an open state, and when a signal that does not satisfy a preset condition is returned to thefilter circuit 11, a suitable filter channel is selected according to the signal, and the signal is subjected to secondary filtering.

Therefore, in the embodiment, the number of the filters is limited to 3, wherein the filter which works first is the filter with the middle filtering range, that is, the second filter, and sends the signal to the first filter for secondary filtering when the bandwidth of the signal is determined to be narrow, and sends the signal to the third filter for secondary filtering when the bandwidth ratio is determined to be wide.

Finally, the embodiment of the present application further provides an electronic device, which includes afilter circuit 11 and other circuits, and further includes thesignal detection circuit 15 mentioned in the above embodiment, where the circuit is configured to obtain a parameter of a current signal, and detect whether the parameter of the current signal meets a preset condition. Since the above detailed description is made for each circuit, the detailed description is omitted here.

The electronic device provided by this embodiment includes a radio frequency circuit, which includes acontroller 10, afilter circuit 11, aradio frequency transceiver 12, apower amplifier 13, and anantenna matching circuit 14, and is configured to connect an input end of thefilter circuit 11 to an output end of thecontroller 10, so as to receive a baseband signal and filter the baseband signal, connect an output end of thefilter circuit 11 to an input end of theradio frequency transceiver 12, so as to send the filtered baseband signal to theradio frequency transceiver 12 for modulation, and connect an input end and an output end of thepower amplifier 13 to an output end of theradio frequency transceiver 12 and an input end of theantenna matching circuit 14, so as to amplify power of the filtered baseband signal and perform 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 a part of the amplified signal is out of a required bandwidth range to cause signal leakage in an adjacent channel is avoided.

The radio frequency circuit provided by the present application is described in detail above. The embodiments are described in a progressive manner in the specification, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description. It should be noted that, for those skilled in the art, it is possible to make several improvements and modifications to the present application without departing from the principle of the present application, and such improvements and modifications also fall within the scope of the claims of the present application.

It is further noted that, in the present 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. Also, 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 an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

Claims (10)

1. A radio frequency circuit, comprising: the antenna comprises a controller (10), a filter circuit (11), a radio frequency transceiver (12), a power amplifier (13) and an antenna matching circuit (14);

wherein the input end of the filter circuit (11) is connected with the 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 signals 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 signals and carrying out antenna matching.

2. The radio frequency circuit according to claim 1, further comprising a signal detection circuit (15);

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; a first output end of the signal detection circuit (15) is connected with an 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; and a second output end of the signal detection circuit (15) is connected with an input end of the filter circuit (11) and is used for returning signals which do not meet the preset condition to the filter circuit (11).

3. A radio frequency circuit according to claim 2, wherein the signal detection circuit (15) comprises a mixer, a local oscillator, an intermediate frequency filter, an amplifier and a detector;

a first input end of the mixer is used as an input end of the signal detection circuit (15) and is used for receiving a signal of an amplification frequency of the power amplifier (13), and a second input end of the mixer is connected with the local oscillator and is used for receiving a local oscillation signal and mixing the local oscillation signal with the signal of the amplification frequency to obtain a mixed signal; the input end of the intermediate frequency filter is connected with the output end of the mixer and used for filtering the mixing 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 used for amplifying the intermediate frequency signal, and the input end of the detector is connected with the output end of the amplifier and used for receiving the amplified signal and measuring the maximum frequency and the minimum frequency of the amplified signal.

4. The RF circuit of claim 3, 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.

5. The radio frequency circuit according to any of claims 2 to 4, wherein the filter circuit (11) comprises a plurality of switches and a plurality of filters, the switches and the filters having a one-to-one correspondence;

one switch is connected with the corresponding filter to form a filtering channel; and the filtering channels are connected in parallel and used for switching the corresponding switch to replace the filter for secondary filtering when the amplified baseband signal does not accord with the preset condition.

6. The RF circuit of claim 5, wherein the plurality of switches are single-pole multi-throw switches, and wherein the moving terminals of the single-pole multi-throw switches are in one-to-one correspondence with the filters, respectively.

7. The radio frequency circuit of claim 6, wherein only one of the filters is active at a time.

8. The radio frequency circuit of claim 7, wherein the number of filters is at least 3.

9. An electronic device comprising a radio frequency circuit as claimed in any one of claims 1 to 8.

10. The electronic device of claim 9, wherein the electronic device is a wearable device.

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