RF front-end circuits and their filtering methods, electronic equipment

Abstract

This invention discloses a radio frequency (RF) front-end circuit and its filtering method, as well as an electronic device. The RF front-end circuit includes a first RF path and a second RF path. The first RF path is used to transmit a first signal, and the second RF path is used to transmit a second signal. The first signal and the second signal correspond to different frequency bands. Each RF path includes: an input port and an output port; N filters disposed between the input port and the output port, with different cutoff frequencies for the N filters, where N is an integer greater than 1; and a gating unit for selecting at least one of the N filters connected in series between the input port and the output port to form a filtering path. The filtering path is used to reduce interference from signals transmitted in RF paths other than the path itself to signals transmitted in the path itself. This circuit can effectively suppress out-of-band noise and alleviate the problem of mutual interference between different signals in similar or adjacent frequency bands.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and in particular to a radio frequency front-end circuit and its filtering method, as well as an electronic device. Background Technology

[0002] In the field of communication technology, mutual interference caused by overlapping or similar frequency bands is a major pain point in the industry. Aside from soft measures such as power reduction and time division multiplexing, the current hard approach is to increase the sideband suppression capability of filters. However, since ideal filters do not exist, the potential for improving the actual sideband suppression capability of filters is very limited, resulting in an inability to effectively solve the signal interference problem. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the first objective of this invention is to provide a radio frequency front-end circuit that, by selecting filters with different cutoff frequencies to form corresponding filtering paths according to different noise suppression requirements at different frequency points, enhances the noise suppression capability at specific frequency points. This overcomes the problems of weak noise suppression capability of a single filter for adjacent frequency bands and the inability to suppress noise within a frequency band, achieving the technical effect of effectively suppressing out-of-band noise and effectively mitigating the mutual interference problem of different signals in adjacent frequency bands or within a frequency band.

[0004] The second objective of this invention is to provide an electronic device.

[0005] The third objective of this invention is to provide a filtering method for radio frequency front-end circuits.

[0006] To achieve the above objectives, a first aspect of the present invention provides a radio frequency (RF) front-end circuit, comprising: a first RF path and a second RF path, wherein the first RF path is used to transmit a first signal, and the second RF path is used to transmit a second signal, the first signal and the second signal correspond to different frequency bands, and each RF path includes: an input port and an output port; N filters disposed between the input port and the output port, wherein the cutoff frequencies of the N filters are different, and N is an integer greater than 1; and a gating unit for selecting at least one of the N filters connected in series between the input port and the output port to form a filtering path, wherein the filtering path is used to reduce the interference of signals transmitted by RF paths other than the path itself on the signals transmitted by the path itself.

[0007] According to the RF front-end circuit of the present invention, by selecting filters with different cutoff frequencies to form corresponding filtering paths based on different noise suppression requirements at different frequency points, the noise suppression capability at specific frequency points is enhanced. This overcomes the problems of weak noise suppression capability of a single filter for near frequency bands and inability to suppress noise within a frequency band, achieving the technical effect of effectively suppressing out-of-band noise and effectively alleviating the mutual interference problem of different signals in near frequency bands or within a frequency band.

[0008] According to one embodiment of the present invention, the gating unit includes: N-1 first gating switches, which are respectively disposed between two adjacent filters. Each first gating switch includes a first fixed port, a first gating port, and a second gating port. The first fixed port is connected to the previous filter, and the first gating port is connected to the next filter. A second gating switch includes N third gating ports and a second fixed port. The N third gating ports are respectively connected to the N-1 second gating ports and the Nth filter, and the second fixed port is connected to the output port. The first gating switches are used to select whether to turn on the next filter or the second gating switch, and the second gating switches are used to select whether to turn on the first gating switch or the Nth filter.

[0009] According to one embodiment of the present invention, in the first radio frequency path, N filters are high-pass filters and satisfy the relationship: f1 < f2 < f3 < ... < fn, where f1, f2, f3, ..., fn are the cutoff frequencies of the N filters, respectively.

[0010] According to one embodiment of the present invention, the gating unit is further configured to determine the current communication frequency range, determine the filter path to be gated according to the lower limit of the current communication frequency range, and select all filters in the filter path to be gated to operate when the sum of the low-frequency noise suppression capabilities of all filters in the filter path to be gated meets a preset low-frequency suppression requirement.

[0011] According to one embodiment of the present invention, in the second radio frequency path, N filters are low-pass filters and satisfy the relationship: f1>f2>f3>…>fn, where f1, f2, f3, …, fn are the cutoff frequencies of the N filters, respectively.

[0012] According to one embodiment of the present invention, the gating unit is further configured to determine the current communication frequency range, determine the filter path to be gated according to the upper limit of the current communication frequency range, and select all filters in the filter path to be gated to operate when the sum of the high-frequency noise suppression capabilities of all filters in the filter path to be gated meets a preset high-frequency suppression requirement.

[0013] To achieve the above objectives, a second aspect of the present invention provides an electronic device including the aforementioned radio frequency front-end circuit.

[0014] The electronic device according to the embodiments of the present invention, by employing the aforementioned radio frequency front-end circuit, overcomes the problems of weak noise suppression capability of a single filter for near-band frequencies and inability to suppress noise within a frequency band, and achieves the technical effect of effectively suppressing out-of-band noise and effectively alleviating the mutual interference problem of different signals in near-band frequencies or within a frequency band.

[0015] To achieve the above objectives, a third aspect of the present invention proposes a filtering method for a radio frequency (RF) front-end circuit. The RF front-end circuit includes a first RF path and a second RF path. The first RF path is used to transmit a first signal, and the second RF path is used to transmit a second signal. The first signal and the second signal correspond to different frequency bands. Each RF path includes an input port, an output port, N filters disposed between the input port and the output port, and a gating unit. The gating unit is used to select at least one of the N filters connected in series between the input port and the output port to form a filtering path. The filtering path is used to reduce the interference of signals transmitted in a different RF path to signals transmitted in the RF path itself. The N filters have different cutoff frequencies, and N is an integer greater than 1. The method includes: determining the current communication frequency range; determining the filtering path to be selected based on the current communication frequency range; and selecting all filters in the filtering path to be selected for operation.

[0016] The filtering method of the radio frequency front-end circuit according to the present invention determines the current communication frequency range, determines the filter path to be selected based on the current communication frequency range, and selects all filters in the filter path to be selected to work. In order to select filters with different cutoff frequencies to form corresponding filter paths according to different noise suppression requirements at different frequency points, the method enhances the noise suppression capability at specific frequency points, overcomes the problem that the noise suppression capability of a single filter is weak for nearby frequency bands and cannot suppress noise within the frequency band, and achieves the technical effect of effectively suppressing out-of-band noise and effectively alleviating the mutual interference problem of different signals in nearby frequency bands or within the frequency band.

[0017] According to one embodiment of the present invention, when the N filters in the first radio frequency path are high-pass filters and satisfy the relationship f1 < f2 < f3 < ... < fn, the filter path to be selected is determined according to the lower limit of the current communication frequency range, and when the sum of the low-frequency noise suppression capabilities of all filters in the filter path to be selected meets the preset low-frequency suppression requirements, all filters in the filter path to be selected are selected to work, wherein f1, f2, f3, ..., fn are the cutoff frequencies of the N filters.

[0018] According to one embodiment of the present invention, when the N filters in the second radio frequency path are low-pass filters and satisfy the relationship f1>f2>f3>…>fn, the filter path to be selected is determined according to the upper limit of the current communication frequency range, and when the sum of the high-frequency noise suppression capabilities of all filters in the filter path to be selected meets the preset high-frequency suppression requirements, all filters in the filter path to be selected are selected to work, wherein f1, f2, f3, …, fn are the cutoff frequencies of the N filters.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a radio frequency front-end circuit according to an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of the first radio frequency path of a radio frequency front-end circuit according to an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the structure of the second radio frequency path of a radio frequency front-end circuit according to an embodiment of the present invention;

[0023] Figure 4 This is a structural block diagram of an electronic device according to an embodiment of the present invention;

[0024] Figure 5 This is a flowchart of a filtering method for a radio frequency front-end circuit according to an embodiment of the present invention. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0026] The following description, with reference to the accompanying drawings, describes the radio frequency front-end circuit, its filtering method, and electronic equipment proposed in the embodiments of the present invention.

[0027] Figure 1 This is a schematic diagram of a radio frequency front-end circuit according to an embodiment of the present invention. (Refer to...) Figure 1As shown, the radio frequency front-end circuit 1000 includes a first radio frequency path 100 and a second radio frequency path 200. The first radio frequency path 100 is used to transmit a first signal, and the second radio frequency path 200 is used to transmit a second signal. The first signal and the second signal correspond to different frequency bands. The different frequency bands of the first signal and the second signal can be completely non-overlapping or partially overlapping.

[0028] The first RF path 100 includes an input port 110, an output port 120, N filters 130 disposed between the input port 110 and the output port 120, and a gating unit 140. The N filters 130 have different cutoff frequencies, and N is an integer greater than 1. The gating unit 140 is used to select at least one of the N filters 130 connected in series between the input port 110 and the output port 120 to form a filtering path. This filtering path is used to reduce interference from signals transmitted in a different RF path to signals transmitted in the RF path itself. The second RF path 200 has the same structure as the first RF path 100; please refer to the relevant description of the first RF path 100 for further details.

[0029] It should be noted that the input port and output port in this application do not represent the direction of signal flow. The signal can flow from the input port to the output port or from the output port to the input port. For ease of description, the following description will use the term "signal from input port to output port". However, this should not be construed as a limitation of this application.

[0030] Specifically, for noise suppression between different frequency bands (i.e., completely non-overlapping), such as signal A and signal B, signal A corresponds to the first RF path 100 and signal B corresponds to the second RF path 200. During the transmission of signal A and signal B, since the RF paths used are in the same circuit, signal B will generate noise and interfere with signal A. Therefore, it is necessary to suppress the noise of signal A through the filter in the first RF path 100. Similarly, the noise generated by signal A will interfere with signal B. Therefore, it is necessary to suppress the noise of signal B through the filter in the second RF path 200.

[0031] When noise suppression is required for signal A, one or more filters can be selected from N filters 130 and connected in series between input port 110 and output port 120 according to the noise suppression capability requirements corresponding to signal A (which may include the noise frequency to be suppressed and the required suppression capability). For example, filters F1 and F2 can be selected to form a filtering path. That is, the gating unit 140 controls the input port 110 to be connected to filter F1, filter F1 to be connected to filter F2, and filter F2 to be connected to output port 120 to form a filtering path. At this time, signal A enters from input port 110, is filtered by filter F1 and filter F2 in sequence, and is output from output port 120. Since filters F1 and F2 have different cutoff frequencies, their noise suppression capabilities are also different. Signal A undergoes two noise suppression processes, and its suppression capability is the sum of the suppression capabilities of the two filters. Therefore, compared to using a single filter for noise suppression, it can achieve a suppression capability that a single filter cannot achieve. This overcomes the problem that a single filter has weak noise suppression capability in close frequency bands, thus achieving the technical effect of effectively suppressing out-of-band noise and effectively mitigating the interference problem of different signals in close frequency bands.

[0032] When noise suppression is required for signal B, the suppression process is the same as that for signal A. For details, please refer to the noise suppression process for signal A. The specific process will not be repeated here.

[0033] For noise suppression within the same frequency band (i.e., partially overlapping), such as signals C and D, where signals C and D operate in frequency division multiplexing mode and their frequency points / bands are relatively close, signal C corresponds to the first RF path 100 and signal D corresponds to the second RF path 200. The noise generated by signal D will interfere with signal C, so a filter in the first RF path 100 is needed to suppress the noise of signal C. Similarly, the noise generated by signal C will interfere with signal D, so a filter in the second RF path 200 is needed to suppress the noise of signal D.

[0034] When noise suppression of the C signal is required, one or more filters can be selected from N filters 130 and connected in series between the input port 110 and the output port 120 according to the noise suppression capability requirement of the C signal for the D signal, so as to form a filtering path. For example, filters F1 and F2 can be selected to form a filtering path. That is, the gating unit 140 controls the input port 110 to be connected to filter F1, filter F1 to be connected to filter F2, and filter F2 to be connected to the output port 120, so as to form a filtering path. At this time, the C signal flows from the input port. The signal enters through port 110, is filtered sequentially by filters F1 and F2, and then outputs from port 120. When noise suppression of the D signal is required, one or more filters can be selected from N filters 230 and connected in series between input port 210 and output port 220 according to the noise suppression capability requirements of the D signal for the C signal. This forms a filtering path. For example, filter F1 can be selected to form a filtering path. In this case, the D signal enters from input port 210, is filtered by filter F1, and then outputs from output port 220. The C and D signals correspond to different filtering paths. By using different filtering paths to suppress noise in the C and D signals, the problem of noise suppression within the frequency band that a single filter cannot handle can be effectively solved, and the mutual interference problem of different signals within the frequency band can be effectively alleviated.

[0035] In the above embodiments, by selecting filters with different cutoff frequencies to form corresponding dynamic filtering paths according to different suppression requirements for noise at different frequency points, the noise suppression capability at specific frequency points is enhanced. This overcomes the problem that a single filter has weak noise suppression capability for near frequency bands and cannot suppress noise within a frequency band. It achieves the technical effect of effectively suppressing out-of-band noise and effectively alleviating the mutual interference problem of different signals in near frequency bands or within a frequency band.

[0036] In some embodiments, reference Figure 2 As shown, the gating unit 140 includes N-1 first gating switches (such as SW1, SW2, etc.) and a second gating switch 141. The N-1 first gating switches are respectively disposed between two adjacent filters. Each first gating switch includes a first fixed port, a first gating port, and a second gating port. The first fixed port is connected to the previous filter, and the first gating port is connected to the next filter. The second gating switch 141 includes N third gating ports and one second fixed port. The N third gating ports are respectively connected to the N-1 second gating ports and the Nth filter, and the second fixed port is connected to the output port. The first gating switches are used to select whether to turn on the next filter or the second gating switch 141, and the second gating switch 141 is used to select whether to turn on the first gating switch or the Nth filter.

[0037] Specifically, refer to Figure 2 As shown, the first first selector switch SW1 is positioned between the first filter F1 and the second filter F2. The first fixed port of the first first selector switch SW1 is connected to the first filter F1, the first selector port of the first first selector switch SW1 is connected to the second filter F2, and the second selector port of the first first selector switch SW1 is connected to the first third selector port of the second selector switch 141. The first first selector switch SW1 is used to select whether to connect the first filter F1 to the second filter F2, or to the second selector switch 141. The connection methods for the second first selector switches SW2, ..., the (N-1)th first selector switches SWN-1 are the same as those for the first first selector switch SW1, and will not be elaborated further here. In addition, the first filter F1 is also connected to the input port 110, the Nth filter FN is also connected to the Nth third gating port of the second gating switch 141, and the second fixed port of the second gating switch 141 is connected to the output port 120.

[0038] Under the action of N-1 first and second gating switches 141, one or more filters connected in series among the N filters 130 can be selected to form the required filtering path. For example, when it is determined that one filter is needed based on the noise suppression capability requirement corresponding to the signal, the first fixed port of the first gating switch SW1 is connected to its own second gating port, so that the first filter F1 is connected to the first third gating port of the second gating switch 141. At the same time, the second fixed port of the second gating switch 141 is connected to its own first third gating port, so that the first filter F1 is connected to the output port 120. At this time, the first filter F1 is connected to the input port 110 and the output port 120 to form a filtering path.

[0039] For example, when the noise suppression capability requirement corresponding to the signal determines that i (2≤i≤N-1) filters are needed, the first fixed ports of the first first gating switch SW1 to the (i-1)th first gating switch SWi-1 are all connected to their own first gating ports, so that the first filter F1 to the i-th filter Fi are connected in series. The first fixed terminal of the i-th first gating switch SWi is connected to its own second gating port, so that the i-th filter Fi is connected to the i-th third gating port of the second gating switch 141. At the same time, the second fixed port of the second gating switch 141 is connected to its own i-th third gating port, so that the i-th filter Fi is connected to the output port 120. At this time, the first filter F1 to the i-th filter Fi are connected in series and then connected to the input port 110 and the output port 120 to form a filtering path composed of multiple filters connected in series.

[0040] For example, when it is determined that N filters are needed based on the noise suppression capability requirements corresponding to the signal, the first fixed ports of the first first gating switch SW1 to the (N-1)th first gating switch SWN-1 are all connected to their own first gating ports, so that the first filter F1 to the Nth filter FN are connected in series. At the same time, the second fixed port of the second gating switch 141 is connected to its own Nth third gating port, so that the Nth filter FN is connected to the output port 120. At this time, the first filter F1 to the Nth filter are connected in series and then connected to the input port 110 and the output port 120 to form a filtering path composed of N filters connected in series.

[0041] It should be noted that the gating unit 240 has the same structure as the gating unit 140; please refer to [reference needed] for details. Figure 3 The description of gating unit 140 will not be repeated here.

[0042] In the above embodiments, by coordinating the N-1 first and second gating switches, N filtering paths containing different numbers of filters are formed. Since the cutoff frequency of each filter is different, the noise suppression capabilities of the resulting filtering paths are also different. This creates N filtering paths with different noise suppression capabilities for selection, thereby achieving out-of-band noise suppression and effectively mitigating the mutual interference problem between different signals in similar or adjacent frequency bands. It should be noted that the N-1 first and second gating switches are active switches and can be controlled via a signal interface.

[0043] In some embodiments, in the first radio frequency path 110, N filters are high-pass filters and satisfy the relationship: f1 < f2 < f3 < ... < fn, where f1, f2, f3, ..., fn are the cutoff frequencies of the N filters, respectively.

[0044] Further reference Figure 2 As shown, the gating unit 140 is also used to determine the current communication frequency range, and to determine the filter path to be gated according to the lower limit of the current communication frequency range. When the sum of the low-frequency noise suppression capabilities of all filters in the filter path to be gated meets the preset low-frequency suppression requirements, all filters in the filter path to be gated are selected to work, so as to realize the low-frequency noise suppression function of the input signal.

[0045] Specifically, the configuration of the RF front-end circuit 1000 can be divided into suppressing low-frequency noise and suppressing high-frequency noise. For example, the first RF path 100 is used to suppress low-frequency noise, and the second RF path 200 is used to suppress high-frequency noise. Here, "high" and "low" are relative to the main frequency. For suppressing low-frequency noise, all N filters in the first RF path 100 can be set as high-pass filters, and each high-pass filter has a different cutoff frequency, such as... Figure 2 As shown, the cutoff frequency of the first filter F1 in the first RF path 100 is f1, the cutoff frequency of the second filter F2 is f2, ..., the cutoff frequency of the Nth filter FN is fn, and f1 < f2 < ... < fn. It should be noted that the cutoff frequency interval between adjacent filters is not limited; it can be a fixed bandwidth or a dynamic bandwidth. That is, the difference between the cutoff frequencies fi and fi-1 can be a fixed value or a variable value, where 1 < i ≤ n.

[0046] When performing low-frequency noise suppression, assuming the current communication frequency range (i.e., the communication occupied spectrum) is v1-v2 (v1≤v2), and the low-frequency noise frequency range to be suppressed (i.e., the noise distribution spectrum) is freq1-freq2 (freq1≤freq2), that is, suppressing noise with frequencies lower than v1, and the required noise suppression capability for the freq1-freq2 frequency range is Q, then the filter path to be selected for low-frequency noise suppression is determined in the following way:

[0047] S11: Determine parameters such as the current communication frequency range.

[0048] Specifically, the gating unit 140 confirms that the current communication frequency range is v1-v2, the low-frequency noise frequency range that needs to be suppressed is freq1-freq2, and the preset noise suppression capability requirement is Q.

[0049] S12: Select the filter closest to frequency v1.

[0050] Specifically, among all filters that satisfy the condition v1-fn>0, the filter with the largest n value is the filter whose cutoff frequency is closest to v1. Let's assume that the selected filter is the j-th filter Fj.

[0051] S13: Calculate the suppression capability of the first filter F1 to the j-th filter Fj in the freq1-freq2 frequency range.

[0052] Specifically, the suppression capability of each filter in the freq1-freq2 frequency range can be calculated based on the cutoff frequency and out-of-band suppression parameters of the filter. Assume that the suppression capability of the first filter F1 in the freq1-freq2 frequency range is a, the suppression capability of the second filter F2 in the freq1-freq2 frequency range is b, ..., and the suppression capability of the j-th filter Fj in the freq1-freq2 frequency range is j.

[0053] S14: Compare the sum of the calculated suppression capabilities of the j filters in the freq1-freq2 frequency range with the required suppression capability of the input signal to determine the candidate pass path.

[0054] Specifically, by comparing the magnitudes of a+b+…+j and Q, if Q≤a+b+…+j, it means that the filtering path formed by the current j filters can meet the requirement of suppressing low-frequency noise in the freq1-freq2 frequency range; if Q>a+b+…+j, it means that the filter with a cutoff frequency less than freq1 cannot meet the requirement of suppressing noise in the freq1-freq2 frequency range. In this case, one can choose to stop gating, or one can choose to continue enabling the subsequent filters by sacrificing the insertion loss of the communication band, that is, enabling a portion of the (j+1)th filter Fj+1 to the Nth filter FN, and finally meeting the requirement of suppressing noise in the freq1-freq2 frequency range.

[0055] S15: Based on the comparison results, the gating unit 140 controls the corresponding gating switch to select the filter path to be selected.

[0056] Specifically, based on the selected filter path determined by the comparison results, the selection unit 140 selects all filters in the filter path to be selected to work in accordance with the above-mentioned control of the first selection switch and the second selection switch 141, so as to realize the function of low-frequency noise suppression of the input signal.

[0057] In the above embodiments, by setting N filters in the first radio frequency path as high-pass filters, determining the filter path to be selected based on the lower limit of the current communication frequency range, and selecting all filters in the filter path to be selected to work when the sum of the low-frequency noise suppression capabilities of all filters in the filter path to be selected meets the preset low-frequency suppression requirements, the first radio frequency path can effectively suppress out-of-band low-frequency noise.

[0058] In some embodiments, in the second RF path 200, N filters are low-pass filters and satisfy the relationship: f1>f2>f3>…>fn, where f1, f2, f3, …, fn are the cutoff frequencies of the N filters, respectively.

[0059] Further reference Figure 3 As shown, the gating unit 240 is also used to determine the current communication frequency range, and determine the filter path to be gated according to the upper limit of the current communication frequency range. When the sum of the high-frequency noise suppression capabilities of all filters in the filter path to be gated meets the preset high-frequency suppression requirements, all filters in the filter path to be gated are selected to work, so as to realize the high-frequency noise suppression function of the input signal.

[0060] Specifically, to suppress high-frequency noise, all N filters in the second RF path 200 can be set as low-pass filters, and each low-pass filter has a different cutoff frequency, such as... Figure 3 As shown, the cutoff frequency of the first filter F1 in the second RF path 200 is f1, the cutoff frequency of the second filter F2 is f2, ..., the cutoff frequency of the Nth filter FN is fn, and f1 > f2 > ... > fn. It should be noted that the cutoff frequency interval between adjacent filters is not limited; it can be a fixed bandwidth or a dynamic bandwidth. That is, the difference between the cutoff frequencies fi-1 and fi can be a fixed value or a variable value, where 1 < i ≤ n.

[0061] When performing high-frequency noise suppression, assuming the current communication frequency range (i.e., the communication occupied spectrum) is v1-v2 (v1≤v2), and the high-frequency noise range to be suppressed (i.e., the noise distribution spectrum) is freq1-freq2 (freq1≤freq2), that is, suppressing noise with frequencies higher than v2, and the required noise suppression capability for the freq1-freq2 frequency range is Q, then the filter path to be selected for high-frequency noise suppression is determined in the following way:

[0062] S21: Determine parameters such as the current communication frequency range.

[0063] Specifically, the gating unit 240 confirms that the current communication frequency range is v1-v2, the high-frequency noise range that needs to be suppressed is freq1-freq2, and the preset noise suppression capability requirement is Q.

[0064] S22: Select the filter closest to frequency v2.

[0065] Specifically, among all filters that satisfy the condition fn-v2>0, the filter with the smallest n value is the filter whose cutoff frequency is closest to v2. Let's assume that the selected filter is the k-th filter Fk.

[0066] S23: Calculate the suppression capability of the first filter F1 to the kth filter Fk in the freq1-freq2 frequency range.

[0067] Specifically, the suppression capability of each filter in the freq1-freq2 frequency range can be calculated based on the cutoff frequency and out-of-band suppression parameters of the filter. Assume that the suppression capability of the first filter F1 in the freq1-freq2 frequency range is a, the suppression capability of the second filter F2 in the freq1-freq2 frequency range is b, ..., and the suppression capability of the kth filter Fk in the freq1-freq2 frequency range is k.

[0068] S24: Compare the sum of the calculated suppression capabilities of the k filters in the freq1-freq2 frequency range with the required suppression capability of the input signal to determine the candidate pass path.

[0069] Specifically, by comparing the magnitudes of a+b+…+k and Q, if Q≤a+b+…+k, it means that the current filtering path composed of k filters can meet the requirement of suppressing low-frequency noise in the freq1-freq2 frequency range; if Q>a+b+…+k, it means that the filter with a cutoff frequency greater than freq2 cannot meet the requirement of suppressing noise in the freq1-freq2 frequency range. In this case, you can choose to stop gating, or you can choose to continue enabling the subsequent filters by sacrificing the insertion loss of the communication band, that is, enabling part of the (k+1)th filter Fk+1 to the Nth filter FN, and finally meet the requirement of suppressing noise in the freq1-freq2 frequency range.

[0070] S25: Based on the comparison results, the gating unit 240 controls the corresponding gating switch to select the filter path to be selected.

[0071] Specifically, based on the selected filter path determined by the comparison results, the selection unit 240 selects all filters in the filter path to be selected to work in accordance with the above-mentioned control of the first selection switch and the second selection switch 241, so as to realize the high-frequency noise suppression function of the input signal.

[0072] In the above embodiments, by setting N filters in the second radio frequency path as low-pass filters, determining the filter path to be selected based on the upper limit of the current communication frequency range, and selecting all filters in the filter path to be selected to work when the sum of the high-frequency noise suppression capabilities of all filters in the filter path to be selected meets the preset high-frequency suppression requirements, the second radio frequency path can effectively suppress out-of-band high-frequency noise.

[0073] By setting the parameters of the filters in the first and second RF paths, the RF front-end circuit can simultaneously have low-frequency noise suppression and high-frequency noise suppression capabilities. At the same time, by selecting the filters in the first and second RF paths, the RF front-end circuit can satisfy both low-frequency and high-frequency noise suppression between different frequency bands, as well as noise suppression within the same frequency band.

[0074] The advantages of this application will be illustrated below with specific examples.

[0075] To illustrate noise suppression across different frequency bands, we will take 2.4G WIFI and the N40 band as examples.

[0076] Assuming the WIFI operates at CH5 (i.e., 2422-2442MHz), the noise frequency range to be suppressed is 2350-2370MHz, and the noise suppression capability needs to reach 50dB. In this case, the first RF path 100 with low-frequency suppression function in the RF front-end circuit 1000 needs to be used, and it is assumed that the first RF path 100 with low-frequency suppression has 4 levels:

[0077] A. The cutoff frequency of the first filter F1 is 2402MHz, and its minimum suppression capability for 2350-2370MHz is 10dB.

[0078] B. The cutoff frequency of the second filter F2 is 2412MHz, and the minimum suppression capability for 2350-2370MHz is 20dB.

[0079] C. The cutoff frequency of the third filter F3 is 2422MHz, and its minimum suppression capability for 2350-2370MHz is 25dB.

[0080] D. The cutoff frequency of the fourth filter, F4, is 2432MHz, and its minimum suppression capability for 2350-2370MHz is 30dB.

[0081] According to the design logic, the sum of the minimum suppression capabilities of the first filter F1, the second filter F2, and the third filter F3 for 2350-2370MHz is 55dB. Therefore, only the first three filter stages are needed, that is, only the first filter F1, the second filter F2, and the third filter F3 are needed, thus meeting the noise suppression capability requirements.

[0082] However, the current noise suppression capabilities of filters are as follows: the passband for the N40 filter is 2300-2400MHz, and the passband for the 2.4GHz Wi-Fi filter is 2402-2482MHz. Since the cutoff frequency of 2402MHz is very close to the noise frequency of 2370MHz, the maximum suppression capability can only reach 30dB (or may even be less). The suppression capability in this application, however, can reach 55dB, which clearly effectively improves the noise suppression capability across different frequency bands.

[0083] For noise suppression within the same frequency band, we will take 2.4G WIFI and BT as examples for explanation.

[0084] Assume that BT operates in frequency hopping mode within the 2402-2432MHz range, while WIFI operates in CH13 (i.e., 2462-2482MHz). For in-band interference, WIFI and BT use different RF paths. Furthermore, since the BT's operating frequency range is lower than WIFI's, BT needs to use the second RF path 200 in the RF front-end circuit 1000, which corresponds to high-frequency suppression, while WIFI needs to use the first RF path 100 in the RF front-end circuit 1000, which corresponds to low-frequency suppression.

[0085] Assume that the second radio frequency path 200 corresponding to BT has 4 levels of high-frequency suppression, and its parameters are as follows:

[0086] A. The cutoff frequency of the first filter F1 is 2482MHz, which has no suppression capability for WIFI in the 2462-2482MHz range;

[0087] B. The cutoff frequency of the second filter F2 is 2452MHz, and its suppression capability for WIFI in the 2462-2482MHz range is 15dB.

[0088] C. The cutoff frequency of the third filter F3 is 2432MHz, and its suppression capability for WIFI in the 2462-2482MHz range is 30dB.

[0089] D. The cutoff frequency of the fourth filter, F4, is 2412MHz, and its suppression capability for WIFI in the 2462-2482MHz range is 50dB.

[0090] Considering the operating frequency of the BT, the first three filters can be enabled without sacrificing the RF performance of the communication frequency. In this case, the noise generated by the BT for WIFI is reduced by 45dB.

[0091] Assume that the first radio frequency path 100 for low-frequency suppression corresponding to WIFI also has 4 levels, with the following parameters:

[0092] A. The cutoff frequency of the first filter F1 is 2402MHz, and its suppression capability for BT in the 2402-2432MHz range is 0dB.

[0093] B. The cutoff frequency of the second filter F2 is 2422MHz, and its suppression capability for BT in the 2402-2432MHz range is 10dB.

[0094] C. The cutoff frequency of the third filter F3 is 2442MHz, and its suppression capability for BT in the 2402-2432MHz range is 20dB.

[0095] D. The cutoff frequency of the fourth filter F4 is 2462MHz, and its suppression capability for BT in the 2402-2432MHz range is 30dB.

[0096] Considering the operating frequency of WIFI, without sacrificing the RF performance of WIFI communication frequency, a 4-level filter can be enabled, which reduces the noise generated by WIFI to BT by 60dB.

[0097] However, current Wi-Fi and BitTorrent use passband filters with the same filtering range, specifically 2402-2482MHz, which lack noise suppression capabilities. This application, however, achieves in-band noise suppression, effectively solving the problem of passband filters' inability to suppress in-band noise.

[0098] In summary, the RF front-end circuit according to the embodiments of the present invention dynamically selects filters with different cutoff frequencies to form corresponding dynamic filtering paths according to different noise suppression requirements at different frequency points, thereby enhancing the noise suppression capability at specific frequency points. This overcomes the problems of weak noise suppression capability of a single filter for nearby frequency bands and inability to suppress noise within a frequency band, achieving the technical effect of effectively suppressing out-of-band noise and effectively alleviating the mutual interference problem of different signals in nearby frequency bands or within a frequency band.

[0099] Corresponding to the above-mentioned radio frequency front-end circuit, this application also provides an electronic device.

[0100] Figure 4 This is a block diagram of an electronic device according to an embodiment of the present invention, with reference to... Figure 4 As shown, the electronic device 10000 includes the aforementioned radio frequency front-end circuit 1000.

[0101] The electronic device according to the embodiments of the present invention, by employing the aforementioned radio frequency front-end circuit, overcomes the problems of weak noise suppression capability of a single filter for near-band frequencies and inability to suppress noise within a frequency band, and achieves the technical effect of effectively suppressing out-of-band noise and effectively alleviating the mutual interference problem of different signals in near-band frequencies or within a frequency band.

[0102] Corresponding to the above-mentioned radio frequency front-end circuit, this application also provides a filtering method for the radio frequency front-end circuit.

[0103] Figure 5 This is a flowchart of a filtering method for a radio frequency front-end circuit according to an embodiment of the present invention. (See reference...) Figure 5 As shown, the filtering method of this RF front-end circuit may include:

[0104] Step S1: Determine the current communication frequency range.

[0105] Step S2: Determine the filter path to be selected based on the current communication frequency range.

[0106] Step S3: Select all filters in the filter path to be selected and start working.

[0107] According to one embodiment of the present invention, when the N filters in the first radio frequency path are high-pass filters and satisfy the relationship f1 < f2 < f3 < ... < fn, the filter path to be selected is determined according to the lower limit of the current communication frequency range, and when the sum of the low-frequency noise suppression capabilities of all filters in the filter path to be selected meets the preset low-frequency suppression requirements, all filters in the filter path to be selected are selected to work, wherein f1, f2, f3, ..., fn are the cutoff frequencies of the N filters.

[0108] According to one embodiment of the present invention, when the N filters in the second radio frequency path are low-pass filters and satisfy the relationship f1>f2>f3>…>fn, the filter path to be selected is determined according to the upper limit of the current communication frequency range, and when the sum of the high-frequency noise suppression capabilities of all filters in the filter path to be selected meets the preset high-frequency suppression requirements, all filters in the filter path to be selected are selected to work, wherein f1, f2, f3, …, fn are the cutoff frequencies of the N filters.

[0109] It should be noted that for the description of the filtering method of the RF front-end circuit in this application, please refer to the description of the RF front-end circuit in this application, and will not be repeated here.

[0110] According to the filtering method of the present invention, by selecting filters with different cutoff frequencies to form corresponding filtering paths based on different suppression requirements for noise at different frequency points, the noise suppression capability at specific frequency points is enhanced. This overcomes the problems of weak noise suppression capability of a single filter for near frequency bands and inability to suppress noise within a frequency band, and achieves the technical effect of effectively suppressing out-of-band noise and effectively alleviating the mutual interference problem of different signals in near frequency bands or within a frequency band.

[0111] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0112] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0113] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0114] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A radio frequency front-end circuit, characterized by include: A first radio frequency (RF) path and a second RF path, wherein the first RF path is used to transmit a first signal, and the second RF path is used to transmit a second signal, wherein the first signal and the second signal correspond to different frequency bands, and each RF path includes: Input ports and output ports; N filters are configured between the input port and the output port, wherein the cutoff frequencies of the N filters are different, and N is an integer greater than 1; A gating unit is used to select at least one of the N filters connected in series between the input port and the output port to form a filtering path. The filtering path is used to reduce the interference of signals transmitted in the radio frequency path other than the radio frequency path it is in on the signals transmitted in the radio frequency path it is in. In the first radio frequency path, the N filters are high-pass filters and satisfy the relationship: f1 < f2 < f3 < ... < fn, where f1, f2, f3, ..., fn are the cutoff frequencies of the N filters; or, in the second radio frequency path, the N filters are low-pass filters and satisfy the relationship: f1 > f2 > f3 > ... > fn, where f1, f2, f3, ..., fn are the cutoff frequencies of the N filters. The gating unit is further configured to determine the current communication frequency range as v1-v2, the low-frequency noise frequency range to be suppressed as freq1-freq2, and the preset noise suppression capability requirement as Q. The filter whose cutoff frequency is closest to frequency v1 is selected as the j-th filter Fj. The suppression capabilities of the first filter F1 to the j-th filter Fj for the freq1-freq2 frequency range are calculated. The sum of the calculated suppression capabilities of the j filters for the freq1-freq2 frequency range is compared with the noise suppression capability requirement to determine the filter paths to be gated. When the sum of the low-frequency noise suppression capabilities of all filters in the filter paths to be gated meets the preset low-frequency suppression requirement, all filters in the filter paths to be gated are selected and put into operation. When the sum of the low-frequency noise suppression capabilities of all filters in the filter paths to be gated does not meet the preset low-frequency suppression requirement, gating is stopped, or some of the (j+1)-th filters Fj+1 to the N-th filters FN are enabled until the preset low-frequency suppression requirement is met, 1 < j ≤ N; or... The gating unit is also configured to determine that a current communication frequency interval is v1-v2, a high-frequency noise frequency interval to be suppressed is freq1-freq2, and a preset noise suppression capability requirement is Q, select a filter closest to the frequency v2 as the kth filter Fk, calculate a suppression capability of the first filter F1 to the kth filter Fk on the freq1-freq2 frequency interval respectively, compare a sum of the suppression capabilities of the k filters on the freq1-freq2 frequency interval with the noise suppression capability requirement, determine a filter channel to be gated, and enable all filters in the filter channel to be gated to work when a sum of suppression capabilities of all filters in the filter channel to be gated on the high-frequency noise meets a preset high-frequency suppression requirement; and disable the filter channel to be gated or continue to enable part of the k+1th filter Fk+1 to the Nth filter FN until the preset high-frequency suppression requirement is met, 1 2. The radio frequency front-end circuit of claim 1, wherein, The gating unit comprises: N-1 first gating switches, the N-1 first gating switches are respectively arranged between adjacent two filters, each first gating switch comprises a first fixed port, a first gating port and a second gating port, the first fixed port is connected with a previous filter, and the first gating port is connected with a next filter; a second gating switch, the second gating switch comprises N third gating ports and a second fixed port, the N third gating ports are connected with N-1 second gating ports and an Nth filter respectively, and the second fixed port is connected with the output port; wherein the first gating switch is configured to select to conduct the next filter or the second gating switch, and the second gating switch is configured to select to conduct the first gating switch or the Nth filter.

3. The radio frequency front-end circuit of claim 1, wherein, The frequency band of the first signal is a WiFi 2.4G frequency band, and the frequency band of the second signal is an N40 frequency band; wherein The first radio frequency channel needs to suppress a noise frequency interval of an N40 frequency band; The lowest suppression capability of the selected filters in the filter channel of the first radio frequency channel on the noise frequency interval to be suppressed is positively correlated with a cutoff frequency.

4. The radio frequency front-end circuit of claim 1, wherein, The frequency band of the first signal is a WiFi 2.4G frequency band, and the frequency band of the second signal is a BT 2.4G frequency band; wherein The first radio frequency channel needs to suppress a noise frequency interval of a BT 2.4G frequency band; the suppression capability of the selected filters in the filter channel of the first radio frequency channel on the noise frequency interval to be suppressed is positively correlated with a cutoff frequency; The second radio frequency channel needs to suppress a noise frequency interval of a WiFi 2.4G frequency band; the suppression capability of the selected filters in the filter channel of the second radio frequency channel on the noise frequency interval to be suppressed is positively correlated with a cutoff frequency.

5. An electronic device, comprising: The radio frequency front-end circuit comprises the radio frequency front-end circuit according to any one of claims 1-4.

6. A filtering method of a radio frequency front-end circuit, characterized by, The radio frequency front-end circuit comprises a first radio frequency path and a second radio frequency path, the first radio frequency path is used for transmitting a first signal, the second radio frequency path is used for transmitting a second signal, the first signal and the second signal correspond to different frequency bands, each radio frequency path comprises an input port, an output port, N filters arranged between the input port and the output port, and a gating unit, the gating unit is used for gating at least one of the N filters to be connected in series between the input port and the output port to form a filter path, and the filter path is used for reducing the interference of the signal transmitted by the non-own radio frequency path on the signal transmitted by the own radio frequency path, wherein the cutoff frequencies of the N filters are different, N is an integer greater than 1, and the method comprises: determining a current communication frequency interval; determining a filter path to be gated according to the current communication frequency interval; gating all filters in the filter path to be gated to work; in the first radio frequency path, the N filters are high-pass filters, and the relationship f1 < f2 < f3 < … < fn is satisfied, wherein f1, f2, f3, …, fn are the cutoff frequencies of the N filters respectively; or in the second radio frequency path, the N filters are low-pass filters, and the relationship f1 > f2 > f3 > … > fn is satisfied, wherein f1, f2, f3, …, fn are the cutoff frequencies of the N filters respectively; determining that the current communication frequency interval is v1-v2, the low-frequency noise frequency interval to be suppressed is freq1-freq2, and the preset noise suppression capability requirement is Q, selecting the filter with the closest cutoff frequency to the frequency v1 as the jth filter Fj, calculating the suppression capability of the first filter F1 to the jth filter Fj on the freq1-freq2 frequency interval, comparing the sum of the suppression capabilities of the j filters on the freq1-freq2 frequency interval with the noise suppression capability requirement, determining the filter path to be gated, and gating all filters in the filter path to be gated to work when the sum of the suppression capabilities of all filters in the filter path to be gated on the low-frequency noise meets the preset low-frequency suppression requirement; when the sum of the suppression capabilities of all filters in the filter path to be gated on the low-frequency noise does not meet the preset low-frequency suppression requirement, stop gating, or continue to enable part of the (j+1)th filter Fj+1 to the Nth filter FN until the preset low-frequency suppression requirement is met, 1 < j ≤ N; or The current communication frequency interval is determined as v1-v2, the high-frequency noise frequency interval to be suppressed is freq1-freq2, and the preset noise suppression capability requirement is Q. A filter with a cutoff frequency closest to the frequency v2 is selected as the kth filter Fk. The suppression capabilities of the 1st filter F1 to the kth filter Fk on the freq1-freq2 frequency interval are calculated respectively. The sum of the suppression capabilities of the k filters on the freq1-freq2 frequency interval is compared with the noise suppression capability requirement to determine a filter pass-through path to be selected. When the sum of the suppression capabilities of all filters in the filter pass-through path to be selected on the high-frequency noise meets the preset high-frequency suppression requirement, all filters in the filter pass-through path to be selected are selected to work. When the sum of the suppression capabilities of all filters in the filter pass-through path to be selected on the high-frequency noise does not meet the preset high-frequency suppression requirement, the selection is stopped, or part of the (k+1)th filter Fk+1 to the Nth filter FN is enabled until the preset high-frequency suppression requirement is met, 1

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