CN114070259A - Leakage signal processing device and filtering system - Google Patents
Leakage signal processing device and filtering system Download PDFInfo
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- CN114070259A CN114070259A CN202210024289.5A CN202210024289A CN114070259A CN 114070259 A CN114070259 A CN 114070259A CN 202210024289 A CN202210024289 A CN 202210024289A CN 114070259 A CN114070259 A CN 114070259A
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H11/00—Networks using active elements
- H03H11/02—Multiple-port networks
- H03H11/04—Frequency selective two-port networks
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H11/00—Networks using active elements
- H03H11/02—Multiple-port networks
- H03H11/34—Networks for connecting several sources or loads working on different frequencies or frequency bands, to a common load or source
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H11/00—Networks using active elements
- H03H11/02—Multiple-port networks
- H03H11/34—Networks for connecting several sources or loads working on different frequencies or frequency bands, to a common load or source
- H03H11/342—Networks for connecting several sources or loads working on different frequencies or frequency bands, to a common load or source particularly adapted for use in common antenna systems
Abstract
The invention relates to the technical field of signal filtering, in particular to a leakage signal processing device and a filtering system. The device is suitable for processing the leakage signal of the multiplex filter; the leakage signal processing device is connected with the multiplex filter and at least comprises an active unit; the active unit is composed of active devices, is suitable for acquiring a transmitting signal or a receiving signal, modulates the transmitting signal or the receiving signal based on a preset frequency range to obtain an interference elimination signal, and eliminates the leakage signal by using the interference elimination signal. By applying the scheme, the signal isolation can be improved by adjusting the preset frequency range.
Description
Technical Field
The invention relates to the technical field of signal filtering, in particular to a leakage signal processing device and a filtering system.
Background
The multiplexing filter has at least one transmitting port, at least one receiving port, and a common port connection antenna, and is a generic term for devices such as a duplex filter and a quadruple filter. The multiplexing filter is a set of filters with non-overlapping frequency ranges, each filter in the set having a passband that does not load the other filter. The multiplexing filter allows filtering of more than one transmit and receive signal with a high degree of isolation between the outputs.
The signal isolation is used for representing the signal leakage degree from a signal sending end to a signal receiving end (or from the signal receiving end to the signal sending end), or the signal leakage degree from a signal common end to the signal sending end.
However, most of the existing schemes for improving the signal isolation of the multiplex filter are implemented by passive devices, the adjustment precision is difficult to be accurately controlled, and the adjustable range is relatively limited.
Disclosure of Invention
The invention aims to solve the problems that: a leakage signal device is provided, so that the adjustment precision is more controllable, and the adjustable frequency range is wider.
To solve the above problem, an embodiment of the present invention provides a leakage signal processing apparatus, which is adapted to process a leakage signal of a multiplexing filter; the multiplexing filter includes: the signal transmitting terminal, the signal common terminal and the signal receiving terminal are arranged, a signal transmitting filter circuit is arranged between the signal transmitting terminal and the signal common terminal, and a signal receiving filter circuit is arranged between the signal receiving terminal and the signal common terminal; a sending signal input by the signal sending end leaks to the receiving signal filter circuit through the signal common end; the receiving signal received by the signal common terminal leaks to the sending signal filtering circuit through the signal common terminal;
the leakage signal processing device is connected with the multiplex filter and at least comprises an active unit; the active unit is composed of an active device, and is adapted to acquire the transmission signal or the reception signal, modulate the transmission signal or the reception signal based on a preset frequency range to obtain an interference cancellation signal, and cancel the leakage signal by using the interference cancellation signal.
Optionally, the preset frequency range is greater than a frequency range in which the passive device is used to modulate the signal.
Optionally, the active unit comprises: and the vector modulator is suitable for carrying out phase modulation and amplitude modulation on the sending signal or the receiving signal in the preset frequency range to obtain a modulated signal which is used as the interference elimination signal.
Optionally, the active unit further comprises: and the sampling coupler is suitable for sampling the sending signal or the receiving signal to obtain a sampling signal, and inputting the sampling signal to the vector modulator.
Optionally, the active unit comprises: a sampling coupler, a vector modulator and a combined coupler; the number of the vector modulators is more than two; wherein: the sampling coupler is suitable for sampling the sending signal or the receiving signal to obtain a sampling signal; the vector modulator is suitable for carrying out phase modulation and amplitude modulation on the sampling signal to obtain a modulation signal; the combined coupler is suitable for synthesizing the modulation signals output by more than two vector modulators to obtain the interference elimination signal.
Optionally, the number of sampling couplers is more than two.
Optionally, the active unit further includes: a delay adapted to delay the transmission signal or the reception signal or the sampling signal.
Optionally, the leakage signal processing apparatus further includes: a passive unit; the passive unit is composed of passive devices.
Optionally, the passive unit is connected in parallel with the active unit.
Optionally, the passive unit includes: a resonator; or three and more pairs of fingers.
Optionally, the passive unit further includes: and the impedance adjusting circuit is suitable for adjusting the impedance of the passive unit, so that the difference value between the impedance of the passive unit and the impedance of the filter circuit where the leakage signal is located is greater than a preset impedance threshold value.
Optionally, the impedance adjusting circuit includes: at least one first capacitor.
The embodiment of the invention also comprises a filtering system, which comprises: the leakage signal processing apparatus according to any one of the above; and a multiplex filter connected to the leakage signal processing means; the leakage signal processing device is suitable for eliminating the leakage signal of the multiplex filter.
Compared with the prior art, the technical scheme of the embodiment of the invention has the following advantages:
by applying the scheme of the invention, the leakage signal processing device at least comprises an active unit, wherein the active unit is composed of active devices, can acquire a transmitting signal or a receiving signal, modulates the transmitting signal or the receiving signal based on a preset frequency range to obtain an interference elimination signal, and eliminates the leakage signal by using the interference elimination signal. Compared with a passive device, the active device can modulate a plurality of set frequency band signals, so that the adjustment precision is more accurate and controllable.
Furthermore, the preset frequency range is set to be larger than the frequency range of modulating the signal by adopting the passive device, so that the active unit formed by the active device can modulate a plurality of set frequency range signals, namely the frequency range of modulating the signal is wider, thereby eliminating the leakage signal in the wider frequency range and effectively improving the signal isolation.
Drawings
Fig. 1 is a schematic diagram of a duplex filter structure;
FIG. 2 is a schematic diagram of a quad filter;
FIG. 3 is a schematic diagram of a position of a leakage signal processing apparatus according to an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of an active cell according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a passive unit according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of another passive element in an embodiment of the invention;
FIG. 7 is a schematic diagram of a passive unit according to another embodiment of the present invention;
FIG. 8 is a schematic diagram of a structure of another passive unit in an embodiment of the present invention;
FIG. 9 is a schematic diagram of the position of another leakage signal processing apparatus according to an embodiment of the present invention;
fig. 10 is a schematic diagram comparing the leakage signal processing apparatus according to the embodiment of the present invention with the prior art to improve the signal isolation.
Detailed Description
Currently, commercial filters mainly include a Surface Acoustic Wave (SAW) filter, a Bulk Acoustic Wave (BAW) filter, a Low Temperature Co-fired ceramic (LTCC) filter, and the like. SAW and BAW filters have the advantages of good insertion loss, small area and the like, so that the SAW and BAW filters are widely applied to consumer electronic terminals such as mobile phones.
Fig. 1 is a schematic structural diagram of a conventional duplex filter 100. Referring to fig. 1, the structure of the duplex filter 100 may include: a signal common terminal 101, a signal transmitting terminal 102, a signal receiving terminal 103, a transmitting signal filter 110, and a receiving signal filter 120; the transmission signal filter 110 may be a SAW filter or a BAW filter; the received signal filter 120 may be a SAW filter, a Double-Mode SAW (DMS) filter, or a BAW filter.
A transmission signal is input from the signal transmitting terminal 102, and ideally, the transmission signal is transmitted from the signal common terminal 101 through the transmission signal filter 110. After the received signal is received by the signal common terminal 101, the received signal is ideally output from the signal receiving terminal 103 to a subsequent processing circuit via the received signal filter 120. The transmission path of the transmission signal and the transmission path of the reception signal are independent of each other.
However, in practical applications, the transmission signal may leak to the signal receiving end 103 through the signal common end 101, and the reception signal may also leak to the signal transmitting end 102 through the signal common end 101.
The signal isolation of the duplex filter is used to characterize the degree of signal leakage from the signal transmitting end 102 to the signal receiving end 103, or from the signal common end 101 to the signal transmitting end 102.
In order to improve the signal isolation, a leakage signal processing device is usually disposed between the signal transmitting end 102 and the signal receiving end 103. In the prior art, the leakage signal processing device is usually formed by passive devices.
Depending on the characteristics of the passive components, it is generally only possible to modulate the transmit signal or the receive signal over a narrow frequency range, and thus to cancel only the leakage signal over a narrow frequency range. Also, the narrow frequency range is fixed, which results in that the adjustment accuracy is difficult to control accurately when using passive devices for leakage signal cancellation.
In view of the above problems, the present invention provides a leakage signal processing apparatus, which at least includes an active unit, where the active unit is composed of an active device, and the apparatus obtains an interference cancellation signal by obtaining a transmission signal or a reception signal, modulating the obtained transmission signal or reception signal based on a preset frequency range, and cancels the leakage signal by using the interference cancellation signal. Compared with a passive device, the active device can generally modulate signals in one or more set frequency ranges, so that the adjustment precision is more accurate and controllable.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
The embodiment of the invention provides a leakage signal processing device which is suitable for processing a leakage signal of a multiplex filter.
First, in order to facilitate understanding of the leakage signal processing apparatus, the multiplexing filter will be described:
in an implementation, the multiplexing filter includes: the signal transmitting terminal, the signal common terminal and the signal receiving terminal are arranged, a signal transmitting filter circuit is arranged between the signal transmitting terminal and the signal common terminal, and a signal receiving filter circuit is arranged between the signal receiving terminal and the signal common terminal; a sending signal input by the signal sending end leaks to the receiving signal filter circuit through the signal common end; the received signal received by the signal common leaks to the transmit signal filter circuit.
In an implementation, the multiplexing filter may include at least one signal transmitting end and at least one signal receiving end.
For example, fig. 2 is a schematic structural diagram of a quadruple filter. Referring to fig. 2, the quad filter 200 may include two signal transmitting terminals and two signal receiving terminals. The two signal transmitting terminals are a first signal transmitting terminal 202 and a second signal transmitting terminal 204, respectively. The two signal receiving ends are respectively a first signal receiving end 203 and a second signal receiving end 205. The two signal transmitting terminals and the two signal receiving terminals share the same signal common terminal 201.
A first transmit signal filter circuit 210 is disposed between the first signal transmitting end 202 and the signal common end 201, and a second transmit signal filter circuit 230 is disposed between the second signal transmitting end 204 and the signal common end 201. A first received signal filter circuit 220 is disposed between the first signal receiving terminal 203 and the signal common terminal 201, and a second received signal filter circuit 240 is disposed between the second signal receiving terminal 205 and the signal common terminal 201.
The first transmit signal filter circuit 210 filters a transmit signal input by the first signal transmitting terminal 202, and transmits the filtered transmit signal through the signal common terminal 201. The second transmit signal filter circuit 230 filters the transmit signal input by the second signal transmitting terminal 204, and transmits the filtered transmit signal through the signal common terminal 201.
The signal received by the signal common terminal 201 passes through the first received signal filter circuit 220 to the first signal receiving terminal 203 and is output to the subsequent circuits. The signal received by the signal common terminal 201 passes through the second received signal filter circuit 240 to the second signal receiving terminal 205 and is output to the subsequent circuits.
In an embodiment of the present invention, the leakage signal processing apparatus, connected to the multiplexing filter, at least includes an active unit; the active unit is composed of active devices and is suitable for acquiring a transmitting signal or a receiving signal in a preset frequency range, modulating the transmitting signal or the receiving signal to obtain an interference elimination signal, and eliminating the leakage signal by using the interference elimination signal.
In implementations where signals are taken from different signal terminals of the multi-pass filter, the filter circuit in which the leakage signal is located may also be different.
For example, in the quad filter shown in fig. 2, a transmission signal input from the first signal transmitting terminal 202 may leak to the first reception signal filter circuit 220, the second reception signal filter circuit 240, and the second transmission signal filter circuit 230 via the signal common terminal 201. The transmission signal inputted from the second signal transmitting terminal 204 may leak to the first received signal filter circuit 220, may leak to the second received signal filter circuit 240, and may leak to the first transmitted signal filter circuit 210 via the signal common terminal 201.
The received signal received by the signal common terminal 201 may leak to the first transmit signal filter circuit 210, the second transmit signal filter circuit 230, and the second receive signal filter circuit 240 if normally output from the first signal receiving terminal 203. The received signal received by the signal common terminal 201 may leak to the first transmit signal filter circuit 210, the second transmit signal filter circuit 230, and the first receive signal filter circuit 220 if it is normally output from the second signal receiving terminal 205.
In general, the power of the transmitted signal can reach 30dBm, the power of the received signal can reach-5 dBm, and the power of the transmitted signal is much greater than that of the received signal, so that the leakage of the transmitted signal is more obvious, and the influence on the signal isolation of the multiplex filter is greater.
In a specific implementation, when the leakage signal is eliminated by the leakage signal processing apparatus, if the acquired signal is a transmission signal, the leakage signal processing apparatus may be connected to three signal terminals of a path where the leakage signal is located. For example, referring to fig. 3, when the path of the leakage signal is: when the signal common terminal 201 → the first transmit signal filter circuit 210 → the first signal transmit terminal 202, the first leakage signal processing device 301 may be provided and connected to the signal common terminal 201, the first signal transmit terminal 202 and the first signal receive terminal 203. When the path of the leakage signal is: when the second signal transmitting terminal 204 → the second transmitting signal filtering circuit 230 → the signal common terminal 201 → the second receiving signal filtering circuit 240 → the second signal receiving terminal 205, a second leakage signal processing apparatus 302 may be provided and connected to the signal common terminal 201, the second signal transmitting terminal 204 and the second signal receiving terminal 205.
In a specific implementation, when the leakage signal is eliminated by the leakage signal processing apparatus, if the acquired signal is a transmission signal, the leakage signal processing apparatus may be connected to any two signal terminals of the multiplexing filter. For example, referring to fig. 3, when a transmission signal is input from the first signal transmitting terminal 202, the first leakage signal processing apparatus 301 may be connected to the signal common terminal 201 and the first signal transmitting terminal 202, or may be connected to the signal common terminal 201 and the first signal receiving terminal 203.
In a specific implementation, when the leakage signal processing device is used to eliminate the leakage signal, if the acquired signal is a received signal, the leakage signal processing device is connected to two signal ends of the multiplex filter to which the leakage signal is connected through the filter. For example, referring to fig. 3, after the received signal is received from the signal common terminal 201, the first leakage signal processing apparatus 301 may be connected to the signal common terminal 201 and the first signal transmitting terminal 202.
The leakage signal processing apparatus can acquire a transmission signal and a reception signal, which are limited time domain signals and thus occupy a wide frequency range in a frequency domain.
In implementations, the active device may intercept a portion of the transmitted or received signal. The transmission signal or the reception signal over a predetermined frequency range is modulated based on the characteristics of the active device. After the part of signals is modulated, the finally obtained interference elimination signal can eliminate the leakage signal in the preset frequency range.
Adopt passive component to constitute leakage signal processing apparatus, because passive component is inductance and electric capacity etc. usually, to the signal that acquires, only can modulate the signal of comparatively limited frequency range, when utilizing the interference cancellation signal that obtains to eliminate leakage signal, only can eliminate leakage signal on the limited frequency range, leakage signal outside this frequency range can leak away from the other end, leads to the signal isolation to be difficult to promote by a wide margin, can't satisfy the requirement of user to signal isolation.
For example, the modulation frequency range of the leakage signal processing device formed by the active device is 100MHz to 200MHz, the modulation frequency range of the leakage signal processing device formed by the passive device is only 100MHz to 120MHz, that is, only the transmission signal and the reception signal in 100MHz to 120MHz can be modulated, and the finally obtained interference elimination signal can only eliminate the leakage signal in the frequency range of 100MHz to 120 MHz. Leakage signals outside the frequency range of 100MHz to 120MHz are leaked out from the other end. The leakage signal processing device constructed by the active device can modulate the transmission signal and the receiving signal on the 100M-200M, and the finally obtained interference elimination signal can eliminate the leakage signal on the 100M-200M. Compared with a leakage signal processing device formed by a passive device, the leakage signal processing device formed by an active device has the advantages that the modulation frequency range of signals can be set, so that the adjustment precision can be more controllable naturally; in addition, the modulation frequency range of the leakage signal processing device formed by the active device is larger than that of the leakage signal processing device formed by the passive device, so that leakage signals in a wider frequency range can be eliminated subsequently, and the signal isolation is effectively improved.
In a particular implementation, the acquired signal is modulated, including modulating the amplitude and phase of the acquired signal. The final interference cancellation signal is close to or the same as the leakage signal in amplitude, but opposite in phase, so that the leakage signal can be cancelled as much as possible by the interference cancellation signal, thereby improving the signal isolation.
In specific implementations, the active unit may be composed of a variety of active devices, and is not particularly limited. Such active devices include, but are not limited to, analog Integrated Circuits (ICs), discrete devices (capacitors, resistors, transistors, etc.), wires, transmission lines, transformers, couplers, waveguides, digital circuit structures, mixed signal structures, etc., may additionally be used, without limitation.
The active devices may be combined in various ways, and are not particularly limited as long as the leakage signal can be eliminated.
In an embodiment of the invention, the active unit may comprise only a vector modulator. The vector modulator is suitable for performing phase modulation and amplitude modulation on a transmitting signal or a receiving signal in a preset frequency range to obtain a modulation signal serving as the interference elimination signal.
In another embodiment of the present invention, the active unit may include only: sampling couplers and vector modulators. The sampling coupler is suitable for sampling a sending signal or a receiving signal to obtain a sampling signal; the vector modulator is suitable for carrying out phase modulation and amplitude modulation on the sampling signal to obtain a modulation signal serving as the interference elimination signal.
In particular implementations, to avoid interfering with the transmission of the acquired signal, the acquired signal may be sampled using a sampling coupler and the sampled signal may be restored to the acquired signal. In particular, the acquired signal may be better recovered based on the sampled signal according to the Nyquist-Shannon sampling theorem (Nyquist-Shannon sampling the term).
In a specific implementation, whether the active unit includes a sampling coupler or not, the number of the vector modulators may be only one, or may be two or more. When the number of the vector modulators is only one, the vector modulator may perform vector modulation on a transmission signal or a reception signal over a preset frequency range. When the number of the vector modulators is more than two, each vector modulator may modulate the transmission signal or the reception signal on different preset frequency bands within a preset frequency range, that is, perform multi-path modulation, and each vector modulator corresponds to one modulation path.
When there is only one vector modulator, the number of sampling couplers may be one or more. When there are more than two vector modulators, one sampling coupler may be provided on each modulation path, or more than two sampling couplers may be provided.
In another embodiment of the present invention, referring to fig. 4, the active cell includes: a sampling coupler 41, a vector modulator, and a combining coupler 44; the number of the vector modulators is more than two. Wherein:
the sampling coupler 41 is adapted to sample a transmission signal or a reception signal to obtain a sampling signal;
the vector modulator is suitable for carrying out phase modulation and amplitude modulation on the sampling signal to obtain a modulation signal;
the combined coupler 44 is adapted to combine the modulation signals output by the two or more vector modulators to obtain the interference cancellation signal.
At this time, each vector modulator only covers one frequency band within the preset frequency range, that is, each vector modulator only modulates a transmission signal or a reception signal on one frequency band, and finally, the combined coupler 44 synthesizes the modulated signals of each frequency band.
In a specific implementation, referring to fig. 4, the vector modulator may include two vectors, that is, a first vector modulator 42 and a second vector modulator 43, where the first vector modulator 42 modulates a transmission signal or a reception signal in a first preset frequency band, and the second vector modulator 43 modulates a transmission signal or a reception signal in a second preset frequency band, and a range of the first preset frequency band is different from a range of the second preset frequency band.
In a specific implementation, the vector modulator may phase modulate the sampled signal such that the resulting interference canceled signal is in phase opposition to the leakage signal. The vector modulator may also amplitude modulate the sampled signal so that the resulting interference canceled signal is close to or equal in amplitude to the leakage signal. The plurality of modulated signals are finally combined by the combiner coupler 44 to obtain an interference cancellation signal, and the leakage signal is cancelled at the leakage signal side.
In specific implementations, the vector modulator may be implemented by using various devices, such as an LC Tank Circuit (LC Tank Circuit), a Varactor diode (Varactor), an Amplifier (Amplifier), an Attenuator (Attenuator), or an inverter (Phase inverter). The magnitude of the amplitude modulation and the magnitude of the phase modulation can be varied by adjusting a Scale factor (Scale factor) of the vector modulator.
In some embodiments, the vector modulator may simultaneously phase modulate and amplitude modulate a transmit signal or a receive signal.
It should be noted that the number of the sampling couplers 41 may be two or more, that is, the acquired signal is sampled twice or more. When a plurality of vector modulators are provided in the active unit, the number of times of sampling of the input signal of each vector modulator may be the same or different. For example, referring to fig. 4, the input signal of the first vector modulator 42 is a sampled signal obtained by 2 times of sampling. The input signal of the second vector modulator 43 is a sampled signal obtained by 1-time sampling. Different input signals may be modulated via different paths, including but not limited to two modulation paths.
In an embodiment of the present invention, referring to fig. 4, the active unit 40 may further include a delay unit 45, and the delay unit 45 is adapted to delay the acquired signal sampling signal.
In a specific implementation, the delay unit 45 delays the acquired signal, and one end of the delay unit may be connected to the signal acquisition end, and the other end of the delay unit may be connected to the sampling coupler 41. The delay unit 45 delays the sampling signal, and one end of the delay unit may be connected to the sampling coupler 41, and the other end of the delay unit may be connected to the vector modulator. When the acquired signal is a transmission signal, the signal acquiring end may be a corresponding signal transmitting end. When the acquired signal is a received signal, the signal acquiring end may be a corresponding signal receiving end.
It should be noted that, in the specific implementation, the position of the delayer 45 is not limited to the above embodiment. After the signal is acquired, the acquired signal may be delayed by the delay unit 45, and then the delayed signal may be sampled by the sampling coupler 41. Or the original signal may be sampled by sampling coupler 41, and then delayed by delay 45. More than two time delay devices can be arranged, and the corresponding signals are delayed by different time delay devices before and after sampling.
In a specific implementation, the delayer 45 may be implemented by using various devices, for example, a bucket-brigade device (bucket-brigade device), a transmission line, a resistance-capacitance network structure, a capacitance-inductance network structure, a resistance-inductance-capacitance network structure, a surface acoustic wave delay line (surface acoustic wave delay line), a filter (filter), an optical delay line (an optical delay line), and the like.
In another embodiment of the present invention, the leakage signal processing apparatus may further include a passive unit at the same time. The passive unit is composed of passive devices. The passive devices include, but are not limited to, Inter-digital transducers (IDTs), discrete devices (inductors, capacitors, resistors), microstrip lines, and the like.
The passive devices may be combined in various ways, and are not particularly limited as long as the leakage signal can be eliminated. And when the passive unit is used for eliminating the leakage signal, the leakage signal processing device is connected with three signal ends of a path where the leakage signal is located. Specifically, the implementation can be performed with reference to the above-mentioned related description about connection between the first leakage signal processing apparatus 301 and the second leakage signal processing apparatus 302 in fig. 3 and the signal terminal of each filter circuit, and details are not repeated here.
In an embodiment of the present invention, the passive unit may include: three and more IDTs, wherein each IDT comprises at least one pair of fingers. The number of IDTs is not limited. The IDTs in the three or more sections may be divided into three sections, a first section of IDTs may be connected to a signal transmitting end, a second section of IDTs may be connected to a signal common end, and a third section of IDTs may be connected to a signal receiving end. The number of IDTs connected to the same signal terminal may be only one, or two or more.
In a specific implementation, the IDT is a metal pattern formed on the surface of a piezoelectric substrate in the shape of a finger cross like two hands, and its function is to realize acoustoelectric transduction. The operation principle of the IDT is as follows: when the input ends of a group of interdigital transducers on the piezoelectric substrate are excited by an alternating electric signal, a periodically distributed electric field is generated, and due to the inverse piezoelectric effect, corresponding elastic deformation can be excited near the surface of the piezoelectric medium, so that the vibration of solid mass points is caused, and the surface acoustic wave which is transmitted along the surface of the matrix is formed. When the surface acoustic wave is transmitted to the other end of the piezoelectric medium, charges are generated at two ends of the metal electrode due to the direct piezoelectric effect, and therefore the other group of interdigital transducers can be used for outputting alternating electric signals. Therefore, the IDT itself has a function of amplitude and phase modulating a signal.
In the embodiment of the invention, the interaction among three or more IDTs can convert the acquired signal from an electrical analog signal into an acoustic analog signal, and then convert the acoustic analog signal into the electrical analog signal and output the electrical analog signal, so that the signal can be eliminated by interference.
In an embodiment of the present invention, referring to fig. 5, the passive unit 50 may include: the three IDTs are a first IDT 51, a second IDT 52 and a third IDT 53. One of the first IDT 51, the second IDT 52 and the third IDT 53 is connected to a signal transmitting end, one is connected to a signal common end, and the remaining one is connected to a signal receiving end, and specifically, which IDT is connected to which signal end is not limited.
For example, the first IDT 51 may be connected to the first signal transmitting end 202, the second IDT 52 may be connected to the signal common end 201, and the third IDT 53 may be connected to the first signal receiving end 203.
In another embodiment of the present invention, referring to fig. 6, the passive unit 60 may include: the four IDTs are a first IDT 61, a second IDT 62, a third IDT 63 and a fourth IDT 64, respectively. The first IDT 61 and the third IDT 63 may be connected to the same signal terminal (e.g., the first signal transmitting terminal 202). The second IDT 62 may be connected to the signal common terminal 201, and the fourth IDT 64 may be connected to the first signal receiving terminal 203.
In still another embodiment of the present invention, referring to fig. 7, the passive unit 70 may include: the five IDTs are a first IDT 71, a second IDT 72, a third IDT 73, a fourth IDT 74 and a fifth IDT 75, respectively. The second DT 72 and the fourth IDT 74 may be connected to the same signal terminal (e.g., the first signal receiving terminal 203). The first IDT 71 and the third IDT 73 may be connected to the signal common terminal 201, and the fifth IDT 75 may be connected to the second signal transmitting terminal 204.
In another embodiment of the present invention, the passive unit may include: a resonator is provided. The resonator can convert the acquired signal into an acoustic analog signal, then convert the acoustic analog signal into an electrical analog signal, output the electric analog signal, and perform frequency modulation on the acquired signal based on the working frequency range of the filter circuit where the leakage signal is located so as to generate an interference elimination signal meeting the required frequency.
The number of the resonators is not limited, and may be only one, or two or more. The plurality of resonators may be connected in series or in parallel. The resonator may be connected to both ends of a filter circuit in which the leakage signal is located, where one end of the filter circuit in which the leakage signal is located is a signal common end, and the other end is a signal transmitting end or a signal receiving end.
For example, referring to fig. 8, the passive element 80 may include a resonator 81. Assuming that the filter circuit in which the leakage signal is located is a first transmission signal filter circuit, one end of the resonator 81 may be connected to the signal common terminal 201, and the other end may be connected to the first signal transmitting terminal 202.
In a specific implementation, the impedance of the passive unit itself may have a large difference from the impedance of the filter circuit where the leakage signal is located, so that the passive unit may generate a corresponding interference cancellation signal.
In some embodiments, the impedance of the passive element itself may also differ less from the impedance of the filter circuit in which the leakage signal is located. In this case, the passive unit may further include: and the impedance adjusting circuit is suitable for adjusting the impedance of the passive unit, so that the difference value between the impedance of the passive unit and the impedance of the filter circuit where the leakage signal is located is greater than a preset impedance threshold value.
The magnitude of the preset impedance threshold may be set according to actual conditions, and is not limited herein. Moreover, the preset impedance threshold value can change along with environmental changes and is not only a fixed value. By setting the preset impedance threshold, the passive unit can acquire signals over a wider frequency range.
In particular implementations, the impedance adjustment circuit may be implemented using a variety of devices.
In an embodiment of the present invention, the impedance adjusting circuit may include: at least one capacitor. The at least one capacitor may be connected with other components of the passive unit in various ways, and is not particularly limited as long as the impedance of the passive unit can be adjusted.
For example, referring to fig. 5 and 6, the number of the at least one capacitor is 3, which are the first capacitor C1, the second capacitor C2 and the third capacitor C3, respectively. Each capacitor is connected in series with one IDT.
Referring to fig. 7, the number of the at least one capacitor is 4, which are respectively the first capacitor C1, the second capacitor C2, the third capacitor C3 and the fourth capacitor C4. Each capacitor is connected in series with one IDT.
Referring to fig. 8, the number of the at least one capacitor is 2, which are the first capacitor C1 and the second capacitor C2. The first capacitor C1 and the second capacitor C2 are connected in series with the resonator 81.
It is to be understood that the impedance adjusting circuit is not limited to the cases exemplified in the above embodiments. The passive and active units are not limited to those listed in the above embodiments.
In a specific implementation, the leakage signal processing apparatus may further include an active unit and a passive unit, that is, the active unit and the passive unit perform signal cancellation on the filter circuit where the same leakage signal is located.
In a specific implementation, the active unit and the passive unit may process the same leakage signal at the same time, or may process different leakage signals respectively.
When the same leakage signal is processed, the active unit and the passive unit can be connected in parallel or respectively connected with different signal ends. For example, referring to fig. 9, for the duplex filter shown in fig. 1, the leakage signal processing apparatus may include both the active unit 91 and the passive unit 92, which are connected to the signal transmitting terminal 102, the signal common terminal 101, and the signal receiving terminal 103, that is, connected in parallel. Assuming that the filter circuit in which the leakage signal is located is the received signal filter 120, the active unit 91 and the passive unit 92 may modulate the transmission signal. When the acquired signal is a transmission signal, the active unit 91 may be connected to the signal common terminal 101 and the signal transmitting terminal 102, and the passive unit 92 may be connected to the signal common terminal 101 and the signal receiving terminal 103, or the passive unit 92 may be connected to the signal common terminal 101 and the signal transmitting terminal 102, and the active unit 91 may be connected to the signal common terminal 101 and the signal receiving terminal 103.
When different leakage signals are processed, the active unit and the passive unit can be connected with the filter according to the leakage path of the corresponding leakage signal. For example, referring to fig. 9, the active unit 91 may be configured to process a leakage signal of the received signal, and in this case, the active unit 91 may be connected to the signal common terminal 101 and the signal transmitting terminal 102. The passive unit 92 may be configured to process a leakage signal of the transmission signal, and at this time, the passive unit 92 may be connected to the signal common terminal 101 and the signal transmitting terminal 102, may also be connected to the signal common terminal 101 and the signal receiving terminal 103, and may also be connected to the signal common terminal 101, the signal transmitting terminal 102, and the signal common terminal 101.
The inventor tests that the leakage signal processing device provided with the active unit and the passive unit can improve the signal isolation degree and control the phase modulation accuracy more compared with the existing scheme for improving the signal isolation degree.
Specifically, referring to fig. 10, curve s1 represents: and when the leakage signal processing device provided with the active unit and the passive unit eliminates the leakage signal, the signal isolation degree is along with the curve of the frequency change of the acquired signal. Curve s2 represents: a curve that varies with the frequency of the acquired signal when the existing scheme is used to cancel the leakage signal.
When filtering a transmission signal or a reception signal having a frequency range of 2.11GHz-2.17GHz at the region a, the value of the curve s1 is approximately 0.1 to 0.2 units higher than the value of the curve s2 at the same frequency.
The embodiment of the invention also provides a filtering system, which can comprise the leakage signal processing device; and a multiplexing filter connected to the leakage signal processing means. The leakage signal processing device is suitable for eliminating the leakage signal of the multiplex filter.
The multiplex filter includes but is not limited to a duplex filter, a quadruple filter, and other types of filters. The filter circuits of the leakage signals are different, and the structures of the leakage signal processing devices can be the same or different.
For example, referring to fig. 3, the leakage signal processing apparatus may include only an active unit with respect to a leakage signal existing in the first transmission signal filtering circuit 210. The leakage signal processing apparatus may include only a passive unit with respect to a leakage signal existing in the first received signal filtering circuit 220. The leakage signal processing apparatus may include both a passive unit and an active unit with respect to a leakage signal existing in the second transmission signal filtering circuit 230.
According to the scheme of the invention, the multiplexer is arranged on a chip, and the leakage signal processing device can be arranged on a substrate (such as a PCB) externally connected with the chip and externally connected with the multiplexer.
According to the scheme of the invention, the leakage signal processing device can be integrated with the multiplexer on a chip, so that the use area of the packaging substrate can be reduced, and the yield can be improved.
In the embodiment of the present invention, the leakage signal processing apparatus may process a leakage signal of a transmission signal, and may also process a leakage signal of a reception signal, and is not limited herein.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (13)
1. A leakage signal processing apparatus is characterized in that it is adapted to process a leakage signal of a multiplex filter; the multiplexing filter includes: the signal transmitting terminal, the signal common terminal and the signal receiving terminal are arranged, a signal transmitting filter circuit is arranged between the signal transmitting terminal and the signal common terminal, and a signal receiving filter circuit is arranged between the signal receiving terminal and the signal common terminal; a sending signal input by the signal sending end leaks to the receiving signal filter circuit through the signal common end; the receiving signal received by the signal common terminal leaks to the sending signal filtering circuit through the signal common terminal;
the leakage signal processing device is connected with the multiplex filter and at least comprises an active unit; the active unit is composed of an active device, and is adapted to acquire the transmission signal or the reception signal, modulate the transmission signal or the reception signal based on a preset frequency range to obtain an interference cancellation signal, and cancel the leakage signal by using the interference cancellation signal.
2. The leakage signal processing apparatus of claim 1, wherein the predetermined frequency range is greater than a frequency range in which the signal is modulated using a passive device.
3. The leakage signal processing apparatus of claim 1, wherein the active unit comprises: and the vector modulator is suitable for carrying out phase modulation and amplitude modulation on the sending signal or the receiving signal in the preset frequency range to obtain a modulated signal which is used as the interference elimination signal.
4. The leakage signal processing apparatus of claim 3, wherein the active unit further comprises: and the sampling coupler is suitable for sampling the sending signal or the receiving signal to obtain a sampling signal, and inputting the sampling signal to the vector modulator.
5. The leakage signal processing apparatus of claim 1, wherein the active unit comprises: a sampling coupler, a vector modulator and a combined coupler; the number of the vector modulators is more than two; wherein:
the sampling coupler is suitable for sampling the sending signal or the receiving signal to obtain a sampling signal;
the vector modulator is suitable for carrying out phase modulation and amplitude modulation on the sampling signal to obtain a modulation signal;
the combined coupler is suitable for synthesizing the modulation signals output by more than two vector modulators to obtain the interference elimination signal.
6. The leakage signal processing apparatus of claim 4 or 5, wherein the number of sampling couplers is two or more.
7. The leakage signal processing apparatus of claim 5, wherein the active unit further comprises: a delay adapted to delay the transmission signal or the reception signal or the sampling signal.
8. The leakage signal processing apparatus of claim 1, further comprising: a passive unit; the passive unit is composed of passive devices.
9. The leakage signal processing apparatus of claim 8, wherein the passive unit comprises: a resonator; or three and more pairs of fingers.
10. The leakage signal processing apparatus of claim 9, wherein the passive unit further comprises: and the impedance adjusting circuit is suitable for adjusting the impedance of the passive unit, so that the difference value between the impedance of the passive unit and the impedance of the filter circuit where the leakage signal is located is greater than a preset impedance threshold value.
11. The leakage signal processing apparatus of claim 10, wherein the impedance adjusting circuit comprises: at least one capacitor.
12. The leakage signal processing apparatus of claim 8, wherein the passive unit is connected in parallel with the active unit.
13. A filtering system, comprising:
the leak signal processing apparatus according to any one of claims 1 to 12;
and a multiplex filter connected to the leakage signal processing means;
the leakage signal processing device is suitable for eliminating the leakage signal of the multiplex filter.
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| CN202210024289.5A CN114070259A (en) | 2022-01-11 | 2022-01-11 | Leakage signal processing device and filtering system |
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| CN105812019A (en) * | 2016-04-29 | 2016-07-27 | 湖北工业大学 | Adaptive null-steering beam bandwidth self-leakage signal suppression system and method |
| CN105991143A (en) * | 2015-03-20 | 2016-10-05 | 亚德诺半导体集团 | Method of and apparatus for transmit noise reduction at receiver |
| CN111431622A (en) * | 2020-03-20 | 2020-07-17 | 大连理工大学 | Photoelectric fusion continuous wave radar leakage interference elimination device and method |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105991143A (en) * | 2015-03-20 | 2016-10-05 | 亚德诺半导体集团 | Method of and apparatus for transmit noise reduction at receiver |
| CN105812019A (en) * | 2016-04-29 | 2016-07-27 | 湖北工业大学 | Adaptive null-steering beam bandwidth self-leakage signal suppression system and method |
| CN111431622A (en) * | 2020-03-20 | 2020-07-17 | 大连理工大学 | Photoelectric fusion continuous wave radar leakage interference elimination device and method |
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