Filtering method and filter for sensing signals
By performing square root filtering and directional gain compensation on the signal amplitude of the touch screen sensing electrodes, the problems of discontinuity and positional errors in active pen handwriting were solved, and the symmetry and linear recovery of the handwriting were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- FITIPOWER INTEGRATED TECH SHENZHEN INC
- Filing Date
- 2026-03-06
- Publication Date
- 2026-06-30
AI Technical Summary
Because the tip of the active pen may not be precisely positioned above the sensing node, the energy distribution of the active pen received by the sensing electrodes on the touchscreen exhibits asymmetric and nonlinear changes, resulting in discontinuous or incorrectly positioned handwriting.
By receiving the signal amplitudes from multiple sensing electrodes, the maximum and second maximum amplitudes are determined. The maximum amplitude is then used for square root filtering compensation and directional gain compensation to restore the symmetry and linear variation characteristics of the pen tip energy.
It effectively reduced the differences between signal amplitudes, suppressed abnormal changes, and restored the continuity and positional accuracy of the handwriting.
Smart Images
Figure CN122308644A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of touch technology, specifically to a filtering method and filter for sensing signals. Background Technology
[0002] Currently, touch systems consist of a touchscreen and an active pen. The active pen actively emits electromagnetic waves of a specific frequency through its internal driving circuitry, and the sensing electrodes on the touchscreen receive this energy. When the pen tip moves within the sensing area, the electromagnetic field emitted by the pen forms a distribution of intensity related to each sensing electrode on the touchscreen. However, because the pen tip is not necessarily precisely positioned above the sensing node, and the sensing electrodes typically employ a lattice or matrix-like discrete sensing structure, the energy distribution of the pen tip exhibits asymmetrical and nonlinear characteristics. This can lead to problems such as discontinuities or positional errors in the detected pen strokes. Summary of the Invention
[0003] In view of this, this application provides a filtering method and filter for sensing signals, used to recover the symmetry and linear variation characteristics of the energy distribution at the tip of an active pen. The technical solution of this application is as follows: This application provides a filtering method for sensing signals, applied to a touchscreen, the touchscreen including a plurality of sensing electrodes for receiving electromagnetic waves from an active stylus to generate the sensing signals; the filtering method includes: receiving the sensing signals from the plurality of sensing electrodes; acquiring the signal amplitude of each sensing signal; determining the largest amplitude value from the plurality of signal amplitude values, and determining a target sensing electrode corresponding to a second amplitude value; performing square root filtering compensation on the remaining signal amplitude values using the largest amplitude value; performing directional gain compensation on the largest amplitude value using a target amplitude value, the target amplitude being the signal amplitude value of the target sensing electrode after square root filtering compensation; and acquiring the touch point position of the active stylus on the touchscreen based on all the compensated signal amplitude values.
[0004] In one embodiment of this application, the step of using the maximum amplitude value to perform square root filtering compensation on the remaining signal amplitude values includes: multiplying the maximum amplitude value by each of the signal amplitude values to obtain an amplitude product; and taking the square root of each amplitude product to obtain the signal amplitude value after square root filtering compensation.
[0005] In one embodiment of this application, the step of using a target amplitude to perform directional gain compensation on the maximum amplitude includes: obtaining the amplitude ratio of the maximum amplitude to the target amplitude; obtaining a nonlinear gain parameter based on the amplitude ratio and a preset nonlinear function; and correcting the maximum amplitude based on the nonlinear gain parameter to obtain the signal amplitude after directional gain compensation.
[0006] In one embodiment of this application, the step of using the target amplitude to perform directional gain compensation on the maximum amplitude further includes: determining whether the signal amplitude after directional gain compensation is greater than a preset maximum limit value; and when it is determined that the signal amplitude after directional gain compensation is greater than the maximum limit value, determining the maximum limit value as the signal amplitude after directional gain compensation.
[0007] In one embodiment of this application, after acquiring the signal amplitude of each of the sensing signals, the filtering method further includes: zeroing the signal amplitudes that are less than a preset threshold.
[0008] In one embodiment of this application, the filtering method further includes: when the second amplitude value is determined to be zero, obtaining the touch point position of the active pen on the touch screen based on all the signal amplitude values after the square root filtering compensation.
[0009] A second aspect of this application provides a filter for sensing signals, applied to a touchscreen, the touchscreen including multiple sensing electrodes for receiving electromagnetic waves from an active stylus and generating the sensing signals; the filter includes: an amplitude acquisition module for receiving the sensing signals from the multiple sensing electrodes and acquiring the signal amplitude of each sensing signal; an amplitude filtering module for determining the largest amplitude value from the multiple signal amplitude values and determining a target sensing electrode corresponding to a second amplitude value; a first filtering module for performing square root filtering compensation on the remaining signal amplitude values using the largest amplitude value; and a second filtering module for performing directional gain compensation on the largest amplitude value using a target amplitude value, the target amplitude being the signal amplitude of the target sensing electrode after square root filtering compensation; wherein all the compensated signal amplitude values are used to obtain the touch point position of the active stylus on the touchscreen.
[0010] In one embodiment of this application, the first filtering module includes: an amplitude product unit, used to multiply the maximum amplitude by each of the signal amplitudes to obtain an amplitude product; and a square root unit, used to perform square root processing on each of the amplitude products to obtain the signal amplitude after square root filtering compensation.
[0011] In one embodiment of this application, the second filtering module includes: a ratio acquisition unit, used to acquire the amplitude ratio between the maximum amplitude and the target amplitude; a parameter acquisition unit, used to obtain a nonlinear gain parameter based on the amplitude ratio and a preset nonlinear function; and a nonlinear correction unit, used to correct the maximum amplitude based on the nonlinear gain parameter to obtain the signal amplitude after directional gain compensation.
[0012] In one embodiment of this application, the filter further includes a zeroing processing module, used to perform zeroing processing on the signal amplitude values that are less than a preset threshold after acquiring the signal amplitude value of each of the sensed signals.
[0013] It is understood that the filtering method for sensing signals in this application embodiment determines the maximum amplitude value from the signal amplitude values of multiple sensing signals, and determines the target sensing electrode corresponding to the second maximum amplitude value. It uses the maximum amplitude value to perform square root filtering compensation on the remaining signal amplitude values, and uses the maximum amplitude value to perform square root filtering compensation on the remaining signal amplitude values. This can reduce the difference between the remaining signal amplitude values and the maximum amplitude value, suppress abnormal changes between signal amplitude values, and solve the problem of poor linearity between the maximum amplitude value and adjacent signal amplitude values caused by the excessively large maximum amplitude value. This restores the symmetry and linear variation characteristics of the energy distribution of the pen tip of the active pen, thereby solving problems such as discontinuity or positional errors in the handwriting of the active pen. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of a scenario involving a touch screen and an active pen, provided in an embodiment of this application.
[0015] Figure 2 This is a flowchart illustrating a filtering method for a sensing signal provided in an embodiment of this application.
[0016] Figure 3 This is a schematic flowchart of a square root filtering compensation method provided in an embodiment of this application.
[0017] Figure 4 This is a flowchart illustrating a directional gain compensation method provided in an embodiment of this application.
[0018] Figure 5 This is a flowchart illustrating another directional gain compensation method provided in an embodiment of this application.
[0019] Figure 6 This is a flowchart illustrating another filtering method for sensing signals provided in an embodiment of this application.
[0020] Figure 7 This is a schematic block diagram of a filter for sensing signals provided in an embodiment of this application.
[0021] Figure 8 This is a schematic block diagram of a first filtering module provided in an embodiment of this application.
[0022] Figure 9 This is a schematic block diagram of a second filtering module provided in an embodiment of this application.
[0023] Figure 10This is a schematic block diagram of another filter for sensing signals provided in an embodiment of this application. Detailed Implementation
[0024] It should be noted that in the embodiments of this application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone, where A and B can be singular or plural. The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and drawings of this application are used to distinguish similar objects, not to describe a specific order or sequence.
[0025] It should also be noted that the methods disclosed in the embodiments of this application or the methods shown in the flowcharts include one or more steps for implementing the method. Without departing from the scope of the claims, the execution order of multiple steps can be interchanged, and some steps can also be deleted.
[0026] Currently, touch systems consist of a touchscreen and an active pen. The active pen actively emits electromagnetic waves of a specific frequency through its internal driving circuitry, and the sensing electrodes on the touchscreen receive this energy. When the pen tip moves within the sensing area, the electromagnetic field emitted by the pen forms a distribution of intensity related to each sensing electrode on the touchscreen. However, because the pen tip is not necessarily precisely positioned above the sensing node, and the sensing electrodes typically employ a lattice or matrix-like discrete sensing structure, the energy distribution of the pen tip exhibits asymmetrical and nonlinear characteristics. This can lead to problems such as discontinuities or positional errors in the detected pen strokes.
[0027] This application provides a filtering method and filter for sensing signals, used to restore the symmetry and linear variation characteristics of the energy distribution at the tip of an active pen.
[0028] Please refer to Figure 1 , Figure 1 This is a schematic diagram of a scenario of a touch screen and an active pen provided in an embodiment of this application, wherein scenario 10 includes a touch screen 100 and an active pen 101.
[0029] In this embodiment, the touchscreen 100 includes multiple first sensing electrodes 110 and multiple second sensing electrodes 120 orthogonal to the first sensing electrodes 110. The first sensing electrodes 110 and the second sensing electrodes 120 are used to transmit touch signals and receive electromagnetic waves from the active pen 101 to generate the sensing signals. The touchscreen 100 can also transmit uplink signals to the active pen 101 through the sensing electrodes and receive downlink signals transmitted by the active pen 101 through the sensing electrodes to complete the communication interaction between the touchscreen 100 and the active pen 101. The uplink signals include synchronization information, various instructions for controlling the active pen 101, and configuration information, etc. The synchronization information is used to synchronize the time slots between the touchscreen 100 and the active pen 101.
[0030] It can be understood that the first sensing electrode 110 and the second sensing electrode 120 orthogonally form a grid, and the intersection of the first sensing electrode 110 and the second sensing electrode 120 is the sensing node. Since the tip of the active pen 101 may not be precisely located above the sensing node, the signal amplitude distribution of the sensing signal obtained through the sensing electrodes will be asymmetrical and nonlinear, which will cause problems such as discontinuity or positional errors in the detected handwriting of the active pen 101.
[0031] Next, combined Figure 1 This application introduces a filtering method for sensing signals, applied to the touchscreen of the above embodiments. Please refer to [link / reference]. Figure 2 Specifically, it includes the following steps: Step S21: Receive sensing signals from multiple sensing electrodes.
[0032] In this embodiment, a filter may also be provided in the touch screen. After receiving the sensing signal from the sensing electrode, the touch chip of the touch screen can input the sensing signal into the filter so that the filter performs the filtering method described in this application. The filter may also be located within the touch chip and can be constructed by a filtering circuit or a software module; the limitations are not specified herein.
[0033] Step S22: Obtain the signal amplitude of each sensing signal.
[0034] In this embodiment, after obtaining the sensing signals from all sensing electrodes, the filter of the touchscreen first acquires the signal amplitude of each sensing signal. For example, the first sensing electrode of the touchscreen can be a transmitting electrode, the second sensing electrode can be a receiving electrode, the touch chip of the touchscreen is connected to each transmitting electrode and transmits a drive signal to the transmitting electrode, the receiving electrode is used to receive the drive signal through capacitive coupling and convert it into a sensing signal, and the touchscreen may also include a digital sampling circuit connected to each receiving electrode, which digitizes the sensing signal into sensing data and transmits the sensing data to the filter. After demodulating the sensing data, the filter obtains the signal amplitude corresponding to the sensing signal.
[0035] In some embodiments, the filter includes an IQ demodulation circuit, which is used to perform quadrature demodulation processing on the sensed data.
[0036] Step S23: Determine the largest amplitude value from multiple signal amplitude values, and determine the target sensing electrode corresponding to the second largest amplitude value.
[0037] In this embodiment, after obtaining the signal amplitude of each sensing electrode, the filter of the touch screen can sort the multiple signal amplitudes according to their magnitude, and then determine the largest amplitude value and the second largest amplitude value. After determining the second largest amplitude value, information about the target sensing electrode corresponding to the second largest amplitude value is also obtained.
[0038] Step S24: Use the maximum amplitude value to perform square root filtering compensation on the amplitude of the remaining signals.
[0039] In this embodiment, after obtaining the maximum amplitude value, the filter of the touch screen uses the maximum amplitude value to perform square root filtering compensation with the remaining signal amplitude values one by one to obtain the signal amplitude value after square root filtering compensation, so as to maintain the relative energy relationship between the remaining signal amplitude values and the maximum amplitude value, reduce the difference between the remaining signal amplitude values and the maximum amplitude value, and thus suppress abnormal changes in the signal amplitude values.
[0040] Step S25: Perform directional gain compensation on the maximum amplitude using the target amplitude, where the target amplitude is the signal amplitude of the target sensing electrode after square root filtering compensation.
[0041] In this embodiment, after the filter performs square root filtering compensation, it also uses the target amplitude to perform directional gain compensation on the maximum amplitude. Since the target amplitude is the signal amplitude of the target sensing electrode after square root filtering compensation, the target amplitude is also the signal amplitude near the maximum amplitude. Therefore, the maximum amplitude obtained after directional gain compensation can further reduce the difference between the maximum amplitude and the adjacent signal amplitude, and can solve the problem of poor linearity between the maximum amplitude and the adjacent signal amplitude caused by the excessively large maximum amplitude.
[0042] Step S26: Based on the compensated amplitude values of all signals, obtain the touch point position of the active pen on the touch screen.
[0043] In this embodiment, after the filter performs the above-mentioned square root filtering compensation and directional gain compensation processing, it outputs all the compensated signal amplitudes. The touch chip of the touch screen obtains the touch point position on the touch screen based on all the compensated signal amplitudes.
[0044] It is understood that the filtering method for sensing signals in this application embodiment determines the maximum amplitude value from the signal amplitude values of multiple sensing signals, and determines the target sensing electrode corresponding to the second maximum amplitude value. It uses the maximum amplitude value to perform square root filtering compensation on the remaining signal amplitude values, and uses the maximum amplitude value to perform square root filtering compensation on the remaining signal amplitude values. This can reduce the difference between the remaining signal amplitude values and the maximum amplitude value, suppress abnormal changes between signal amplitude values, and solve the problem of poor linearity between the maximum amplitude value and adjacent signal amplitude values caused by the excessively large maximum amplitude value. This restores the symmetry and linear variation characteristics of the energy distribution of the pen tip of the active pen, thereby solving problems such as discontinuity or positional errors in the handwriting of the active pen.
[0045] Please refer to Figure 3 , Figure 3 A flowchart illustrating a square root filtering compensation method provided in this application embodiment specifically includes the following steps: Step S31: Multiply the maximum amplitude by the amplitude of each signal to obtain the amplitude product.
[0046] In this embodiment of the application, when the touch screen filter performs square root filtering compensation, it multiplies the maximum amplitude value with each signal amplitude value to obtain the amplitude product corresponding to each signal amplitude value.
[0047] Step S32: Take the square root of each amplitude product to obtain the signal amplitude after square root filtering compensation.
[0048] In this embodiment, after obtaining the amplitude product, the filter of the touch screen performs square root processing on the amplitude product to obtain the signal amplitude after square root filtering compensation.
[0049] Please refer to Figure 4 , Figure 4 A flowchart illustrating a directional gain compensation method provided in this application embodiment specifically includes the following steps: Step S41: Obtain the amplitude ratio between the maximum amplitude and the target amplitude.
[0050] In this embodiment of the application, when the filter of the touch screen performs directional gain compensation, it first obtains the amplitude ratio between the maximum amplitude and the target amplitude.
[0051] Step S42: Obtain the nonlinear gain parameter based on the amplitude ratio and the preset nonlinear function.
[0052] In this embodiment, after obtaining the amplitude ratio, the filter inputs the amplitude ratio to a preset nonlinear function to obtain the corresponding nonlinear gain parameter.
[0053] Step S43: Correct the maximum amplitude value according to the nonlinear gain parameter to obtain the signal amplitude after directional gain compensation.
[0054] In this embodiment, after obtaining the nonlinear gain parameter, the filter corrects the maximum amplitude value according to the nonlinear gain parameter to obtain the signal amplitude corresponding to the maximum amplitude value after directional gain compensation, so that the maximum amplitude value and the adjacent signal amplitude have a linear transition.
[0055] Please refer to Figure 5 , Figure 5 A flowchart illustrating another directional gain compensation method provided in this application embodiment is shown, specifically including the following steps: Step S51: Obtain the amplitude ratio between the maximum amplitude and the target amplitude.
[0056] Step S52: Obtain the nonlinear gain parameter based on the amplitude ratio and the preset nonlinear function.
[0057] Step S53: Correct the maximum amplitude value according to the nonlinear gain parameter to obtain the signal amplitude after directional gain compensation.
[0058] Step S54: Determine whether the amplitude of the signal after directional gain compensation is greater than the preset maximum limit value.
[0059] Step S55: When the amplitude of the signal after directional gain compensation is greater than the maximum limit value, the maximum limit value is determined to be the amplitude of the signal after directional gain compensation.
[0060] In this embodiment, a maximum limit value is also set in the filter to first limit the maximum amplitude after directional gain compensation from exceeding the maximum limit value, so as to avoid the maximum amplitude being too large and causing poor linear transition with the amplitude of adjacent signals.
[0061] Please refer to Figure 6 , Figure 6 A flowchart illustrating another filtering method for sensing signals provided in an embodiment of this application is shown, specifically including the following steps: Step S61: Receive sensing signals from multiple sensing electrodes.
[0062] Step S62: Obtain the signal amplitude of each sensing signal.
[0063] Step S63: Zero out signal amplitudes that are less than a preset threshold.
[0064] In this embodiment, the touch screen's filter screens out signal amplitudes that are less than a preset threshold and performs zeroing processing, thereby filtering out static noise during touch detection and improving the effect of subsequent amplitude compensation.
[0065] Step S64: Determine the largest amplitude value from multiple signal amplitude values, and determine the target sensing electrode corresponding to the second largest amplitude value.
[0066] Step S65: Use the maximum amplitude value to perform square root filtering compensation on the amplitude of the remaining signals.
[0067] Step S66: Perform directional gain compensation on the maximum amplitude using the target amplitude, where the target amplitude is the signal amplitude of the target sensing electrode after square root filtering compensation.
[0068] Step S67: Based on the compensated amplitude values of all signals, obtain the position of the active pen on the touch screen.
[0069] Step S68: When the second amplitude is determined to be zero, obtain the touch point position of the active pen on the touch screen based on all signal amplitudes after square root filtering compensation.
[0070] In this embodiment, when the filter determines that the second amplitude is zero, directional gain compensation can be omitted, thereby reducing the amount of computation, reducing the power consumption of the touch screen, and improving the efficiency of sensing.
[0071] Please refer to Figure 7 , Figure 7 This is a schematic block diagram of a filter for sensing signals provided in an embodiment of this application, applied to the touch screen of the above embodiment. The filter 700 includes: The amplitude acquisition module 710 is used to receive sensing signals from multiple sensing electrodes and acquire the signal amplitude of each sensing signal.
[0072] The amplitude filtering module 720 is used to determine the largest amplitude value from multiple signal amplitude values and to determine the target sensing electrode corresponding to the second largest amplitude value.
[0073] The first filtering module 730 is used to perform square root filtering compensation on the amplitude of the remaining signals using the maximum amplitude value.
[0074] The second filtering module 740 is used to perform directional gain compensation on the maximum amplitude using the target amplitude, where the target amplitude is the signal amplitude of the target sensing electrode after square root filtering compensation.
[0075] Among them, all the compensated signal amplitudes are used to obtain the touch point position of the active pen on the touch screen.
[0076] In some embodiments, the touch chip of the touch screen includes the filter 700 described above.
[0077] Please refer to Figure 8 , Figure 8 A schematic block diagram of a first filtering module provided in an embodiment of this application, wherein the first filtering module 730 includes: The amplitude product unit 731 is used to multiply the maximum amplitude by the amplitude of each signal to obtain the amplitude product.
[0078] The square root unit 732 is used to perform square root processing on each amplitude product to obtain the signal amplitude after square root filtering compensation.
[0079] Please refer to Figure 9 , Figure 9 A schematic block diagram of a second filtering module provided in an embodiment of this application, wherein the second filtering module 740 includes: The ratio acquisition unit 741 is used to acquire the ratio of the maximum amplitude to the target amplitude.
[0080] The parameter acquisition unit 742 is used to obtain nonlinear gain parameters based on the amplitude ratio and a preset nonlinear function.
[0081] The nonlinear correction unit 743 is used to correct the maximum amplitude value according to the nonlinear gain parameter to obtain the signal amplitude after directional gain compensation.
[0082] Please refer to Figure 10 , Figure 10 A schematic block diagram of another sensing signal filter 700 provided in an embodiment of this application, and... Figure 7 Compared to the filter 700 shown, Figure 10 The filter 700 shown also includes: The zeroing processing module 750 is used to zero out signal amplitudes that are less than a preset threshold after acquiring the signal amplitude of each sensing signal.
[0083] It is understood that the detailed functions and beneficial effects of the filter 700 and its various modules in the above embodiments can be found in the filtering method-related content in the foregoing embodiments, and will not be repeated here.
[0084] This application embodiment also provides a computer storage medium storing a computer program that, when executed by a processor, causes the processor to perform the above-described filtering method for the sensing signal.
[0085] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer storage medium or transmitted through the computer storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., Digital Versatile Discs (DVDs)), or semiconductor media (e.g., solid-state disks (SSDs)).
[0086] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks. Unless otherwise specified, the technical features of this embodiment and its implementation can be combined arbitrarily.
[0087] The embodiments described above are merely preferred embodiments of this application and are not intended to limit the scope of this application. Any modifications and improvements made by those skilled in the art to the technical solutions of this application without departing from the spirit of this application should fall within the protection scope defined by the claims of this application.
Claims
1. A filtering method for a sensed signal, characterized in that, Applied to a touch screen, the touch screen includes multiple sensing electrodes, which are used to receive electromagnetic waves from an active pen and generate the sensing signal; The filtering method includes: Receive the sensing signals from the plurality of sensing electrodes; Obtain the signal amplitude of each of the sensed signals; The largest amplitude value is determined from the plurality of said signal amplitude values, and the target sensing electrode corresponding to the second largest amplitude value is determined; The maximum amplitude value is used to perform square root filtering compensation on the remaining signal amplitude values; Directional gain compensation is performed on the maximum amplitude using a target amplitude, where the target amplitude is the signal amplitude of the target sensing electrode after square root filtering compensation. Based on all the compensated signal amplitudes, the touch point position of the active pen on the touch screen is obtained.
2. The filtering method as described in claim 1, characterized in that, The step of using the maximum amplitude value to perform square root filtering compensation on the remaining signal amplitude values includes: The amplitude product is obtained by multiplying the maximum amplitude value by each of the signal amplitude values; The square root of each amplitude product is taken to obtain the signal amplitude after square root filtering compensation.
3. The filtering method as described in claim 1, characterized in that, The method of using the target amplitude to perform directional gain compensation on the maximum amplitude includes: Obtain the amplitude ratio of the maximum amplitude to the target amplitude; Based on the amplitude ratio and the preset nonlinear function, the nonlinear gain parameter is obtained; The maximum amplitude is corrected according to the nonlinear gain parameter to obtain the signal amplitude after directional gain compensation.
4. The filtering method as described in claim 3, characterized in that, The method of using the target amplitude to perform directional gain compensation on the maximum amplitude also includes: Determine whether the amplitude of the signal after directional gain compensation is greater than a preset maximum limit value; When the amplitude of the signal after directional gain compensation is determined to be greater than the maximum limit value, the maximum limit value is determined to be the amplitude of the signal after directional gain compensation.
5. The filtering method as described in claim 1, characterized in that, After acquiring the signal amplitude of each of the sensed signals, the filtering method further includes: Signal amplitudes that are less than a preset threshold are zeroed out.
6. The filtering method as described in claim 5, characterized in that, The filtering method further includes: When the second amplitude value is determined to be zero, the touch point position of the active pen on the touch screen is obtained based on all the signal amplitude values after the square root filtering compensation.
7. A filter for sensing signals, characterized in that, Applied to a touch screen, the touch screen includes multiple sensing electrodes, which are used to receive electromagnetic waves from an active pen and generate the sensing signal; The filter includes: An amplitude acquisition module is used to receive the sensing signals from the plurality of sensing electrodes and acquire the signal amplitude of each sensing signal; An amplitude filtering module is used to determine the largest amplitude value from a plurality of said signal amplitude values, and to determine the target sensing electrode corresponding to the second largest amplitude value; The first filtering module is used to perform square root filtering compensation on the remaining signal amplitudes using the maximum amplitude value; The second filtering module is used to perform directional gain compensation on the maximum amplitude using a target amplitude, wherein the target amplitude is the signal amplitude of the target sensing electrode after square root filtering compensation; The compensated signal amplitudes are used to obtain the touch point position of the active pen on the touch screen.
8. The filter as described in claim 7, characterized in that, The first filtering module includes: An amplitude product unit is used to multiply the maximum amplitude by each of the signal amplitudes to obtain an amplitude product; The square root unit is used to perform square root processing on each of the amplitude products to obtain the signal amplitude after square root filtering compensation.
9. The filter as described in claim 7, characterized in that, The second filtering module includes: A ratio acquisition unit is used to acquire the ratio of the maximum amplitude to the target amplitude; The parameter acquisition unit is used to obtain the nonlinear gain parameter based on the amplitude ratio and a preset nonlinear function; A nonlinear correction unit is used to correct the maximum amplitude value according to the nonlinear gain parameter to obtain the signal amplitude after directional gain compensation.
10. The filter as described in claim 7, characterized in that, The filter also includes: The zeroing processing module is used to perform zeroing processing on the signal amplitudes that are less than a preset threshold after acquiring the signal amplitude of each of the sensed signals.