Control circuit for electromagnetic digitizer

Abstract

This invention relates to a control circuit for an electromagnetic digitizer, comprising: a transmitting circuit module, N analog switch modules, N drive circuit modules, and N antenna modules; the transmitting circuit module is configured to output a first transmitting signal and a control signal; the N analog switch modules are configured to, when transmitting a signal via the antenna, based on the control signal output by the transmitting circuit module, turn on the port for outputting the first transmitting signal, thereby causing the first transmitting signal to be output via the selected port; the N drive circuit modules are configured to, when transmitting a signal via the antenna, selectively output a second transmitting signal based on the signal output by the corresponding analog switch module; the N antenna modules are configured to, when transmitting a signal via the antenna, transmit the second transmitting signal output by the corresponding drive circuit module. The control circuit can increase the power of the signal transmitted via the antenna of the electromagnetic digitizer to improve the signal-to-noise ratio of the received signal.

Description

Technical Field

[0001] This invention relates to the field of computer input device technology, and more specifically, to a control circuit for an electromagnetic digitizing tablet capable of increasing the power of signals transmitted via an antenna of the tablet. Background Technology

[0002] Existing passive electromagnetic handwriting input devices (i.e., electromagnetic digitizing tablets) connect their antennas to a transmitting circuit (e.g., an MCU chip) and a signal amplification circuit via an analog switching circuit (e.g., a 74HCT4051PW chip). When transmitting a signal, the electromagnetic digitizing tablet's transmitting circuit controls the analog switching circuit to conduct, allowing the transmitted signal to pass through the conducting analog switching circuit and then be transmitted via the antenna. Because the analog switching circuit has a certain resistance when conducting, it reduces the power of the transmitted signal, resulting in a lower signal strength received by the corresponding electromagnetic pen. When the electromagnetic digitizing tablet receives a signal from the electromagnetic pen, a large amplification factor is often required in the signal amplification circuit to amplify the received signal. In this case, if external interference signals are present, these interference signals are received by the antenna and amplified together with the useful signal from the electromagnetic pen by the signal amplification circuit. When the interference signal is large enough (such as when the interference signal on the LCD glass panel, display control board, and backlight driver board is large enough in the case of digital display products), the signal-to-noise ratio of the signal received by the electromagnetic digitizing board will be reduced, which will result in inaccurate coordinates and pressure sensitivity of the calculated electromagnetic pen, and phenomena such as cursor jitter and pressure sensitivity jump.

[0003] Therefore, a technology is needed to improve the signal-to-noise ratio of signals received by electromagnetic digitizers.

[0004] The information disclosed in the background section of this invention is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] In view of the above-mentioned defects in the prior art, the purpose of the present invention is to provide a control circuit for an electromagnetic digitizing board that can increase the power of the signal transmitted through the antenna of the electromagnetic digitizing board to improve the signal-to-noise ratio of the received signal.

[0006] According to an embodiment of the present invention, a control circuit for an electromagnetic digitizing tablet is provided, which is used to increase the power of a signal transmitted via an antenna of the electromagnetic digitizing tablet. The control circuit for the electromagnetic digitizing tablet includes: a transmitting circuit module, N analog switch modules, N driving circuit modules, and N antenna modules; the transmitting circuit module is configured to output a first transmitting signal and a control signal; the N analog switch modules are electrically connected to the transmitting circuit module and configured to, when transmitting a signal via the antenna, based on the control signal output by the transmitting circuit module, turn on the port for outputting the first transmitting signal, thereby causing the first transmitting signal to be output via the selected port; the N driving circuit modules are respectively electrically connected to corresponding analog switch modules among the N analog switch modules and configured to, when transmitting a signal via the antenna, selectively output a second transmitting signal based on the signal output by the corresponding analog switch module; the N antenna modules are respectively electrically connected to corresponding driving circuit modules among the N driving circuit modules and configured to, when transmitting a signal via the antenna, transmit the second transmitting signal output by the corresponding driving circuit module.

[0007] Preferably, each of the N analog switch modules includes a multi-select analog switch chip, the multi-select analog switch chip including a first pin X0 to an Mth pin X M-1 And the common pin Y of the switch.

[0008] Preferably, each of the N driving circuit modules includes M drivers and M resistors, wherein the M resistors are connected in parallel with the M drivers respectively, and are respectively connected to the first pin X0 to the Mth pin X1. M-1 Connect accordingly.

[0009] Preferably, each of the N antenna modules includes M antennas, and the M antennas are respectively connected to the M drivers and the M resistors.

[0010] Preferably, the first terminal of the m-th driver in the n-th driver circuit module of the N driver circuit modules is connected to the m-th pin X of the n-th multiple-choice analog switch chip in the N analog switch modules. m-1 The enable control terminal of the m-th driver is connected to the enable pin of the (n+m)-th multi-select analog switch chip in the N analog switch modules, and the second terminal of the m-th driver is connected to the m-th antenna in the n-th antenna module of the N antenna modules, where n is an integer greater than or equal to 1 and less than or equal to N, and m is an integer greater than or equal to 1 and less than or equal to M.

[0011] Preferably, the transmitting circuit module includes an MCU chip, wherein its first pin I / O 0 to the N+M+3 pin I / O N+M+2 are configured in a strong push-pull mode to output control signals, and its N+M+4 pin I / O N+M+3 is configured in a strong push-pull mode to output a first transmit signal when transmitting signals via the antenna, and is configured in a high-impedance mode when receiving signals via the antenna to receive signals received via the antenna. The control signals include an enable control signal and a selection control signal. The first pin I / O 0 to the N+M pin I / O N+M-1 are respectively connected to the enable pins of the first multi-select analog switch chip to the Nth multi-select analog switch chip in the N analog switch modules and / or the enable control terminals of the corresponding drivers in the N driving circuit modules to output enable control signals. The N+M+1 pin I / O N+M to N+M+3 pin I / O N+M+2 is connected to the selection input pins of the first multi-select analog switch chip to the Nth multi-select analog switch chip to output a selection control signal, wherein the first transmitted signal is a pulse signal.

[0012] Preferably, each of the M drivers is connected to a power supply and a ground terminal to be powered by the power supply and selectively output a second transmission signal, the voltage value of the second transmission signal corresponding to the high-level voltage value of the first transmission signal.

[0013] Preferably, both the enable control terminal of the driver and the enable pin of the multi-select analog switch chip are low-level enabled.

[0014] Preferably, when the antenna transmits a signal, the MCU chip outputs a low-level enable control signal via a corresponding pin to the enable control terminal of the driver connected to the transmitting antenna, the enable pin of the multi-select analog switch chip connected to the transmitting antenna, and the enable pin of another multi-select analog switch chip connected to the enable control terminal of the driver connected to the transmitting antenna. It also outputs a high-level enable control signal to the enable control terminals of other drivers and the enable pins of other multi-select analog switch chips. When the antenna receives a signal, the MCU chip outputs a low-level enable control signal via a corresponding pin to the enable pin of the multi-select analog switch chip connected to the receiving antenna. It also outputs a high-level enable control signal to the enable pins of other multi-select analog switch chips and the enable control terminals of all drivers.

[0015] Preferably, when the antenna transmits a signal, the driver connected to the antenna transmitting the signal is configured to selectively output a second transmit signal based on a high-level signal or a low-level signal received from the multiple-choice analog switch chip.

[0016] Preferably, when the antenna receives a signal, the signal received from the antenna is transmitted to the pin of the multiplexer analog switch chip via a resistor connected in parallel with the driver.

[0017] Preferably, the multiple-choice analog switch chip includes a 2-to-1 analog switch chip, a 4-to-1 analog switch chip, an 8-to-1 analog switch chip, and a 16-to-1 analog switch chip, and the driver includes a tri-state gate driver.

[0018] The present invention has the following beneficial effects:

[0019] 1) The power of the electromagnetic digitizing tablet's transmitted signal has been increased, resulting in a stronger signal received by the corresponding electromagnetic pen. This strengthens the tablet's signal when receiving the pen's signal, thereby improving the signal-to-noise ratio of the received signal. This allows the electromagnetic digitizing tablet to function normally even in the presence of interference.

[0020] 2) The enable control signal for the multi-select analog switch chip is multiplexed, therefore it does not increase the number of pins required by the MCU chip.

[0021] 3) Minimal modifications are required to the software of the MCU chip. Attached Figure Description

[0022] Some aspects and / or other aspects of the invention will become apparent and more readily understood from the following description of exemplary embodiments presented in conjunction with the accompanying drawings, in which:

[0023] Figure 1 A schematic diagram of the control circuit of an electromagnetic digitizing board according to an embodiment of the present invention is shown;

[0024] Figure 2 An equivalent circuit diagram of the driver in the control circuit of an electromagnetic digitizing board according to an embodiment of the present invention is shown;

[0025] Figure 3 A schematic diagram showing a three-state gate driver in the control circuit of an electromagnetic digitizing board according to an exemplary embodiment of the present invention is provided.

[0026] Figure 4A and Figure 4B A schematic diagram showing the driver as a discrete component in the control circuit of an electromagnetic digitizing board according to an exemplary embodiment of the present invention; and

[0027] Figure 5 A schematic diagram of a driver in the control circuit of an electromagnetic digitizing board according to another exemplary embodiment of the present invention is shown. Detailed Implementation

[0028] Various changes and exemplary embodiments can be made in this invention, such that particular exemplary embodiments are shown in the accompanying drawings and described in detail in the specification. However, it should be understood that the exemplary embodiments are not intended to limit the invention to the specific forms disclosed, but rather that the invention includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

[0029] In describing each drawing, similar reference numerals are used for similar components. The terms "first," "second," etc., may be used to describe various components, but these components should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first component may be referred to as a second component without departing from the scope of the invention, and similarly, a second component may be referred to as a first component. The term "and / or" includes a combination of or any one of the related listed items.

[0030] Figure 1 A schematic diagram of the control circuit of an electromagnetic digitizing tablet according to an embodiment of the present invention is shown. Figure 1 As shown, the control circuit of the electromagnetic digitizing board according to an embodiment of the present invention includes a transmitting circuit module S1 and N analog switch modules SW1 to SW2. N N drive circuit modules U1 to U N and N antenna modules A1 to A N The transmitting circuit module S1 is configured to output a first transmitting signal V1 and a control signal; the N analog switch modules SW1 to SW N Electrically connected to the transmitting circuit module S1, and configured to, when transmitting a signal via the antenna, based on a control signal output by the transmitting circuit module S1, turn on the port for outputting the first transmitted signal V1, thereby causing the first transmitted signal V1 to be output via the selected port; the N driving circuit modules U1 to U N Each of the N analog switch modules SW1 to SW N The corresponding analog switch modules are electrically connected and configured to selectively output a second transmission signal V2 based on the signal output by the corresponding analog switch module when a signal is transmitted via the antenna; the N antenna modules A1 to A N Each of the N drive circuit modules U1 to U N The corresponding drive circuit module is electrically connected and configured to transmit a second transmission signal V2 output by the corresponding drive circuit module when a signal is transmitted via the antenna.

[0031] According to an embodiment of the present invention, the N analog switch modules SW1 to SW N It includes N multiplexer analog switch chips, each multiplexer analog switch chip having a first pin X0 to an Mth pin X...M-1 And the switch common pin Y, and the multiple-choice analog switch chip includes at least one of a two-to-one analog switch chip, a four-to-one analog switch chip, an eight-to-one analog switch chip, and a sixteen-to-one analog switch chip.

[0032] The N driving circuit modules U1 to U N Each of the components includes M drivers and M resistors, wherein the M resistors are connected in parallel with the M drivers respectively, and are connected to the first pin X0 to the Mth pin X0 respectively. M-1 Correspondingly connected, wherein the resistors have the same resistance value (e.g., their resistance value is approximately tens of ohms to thousands of ohms).

[0033] The N antenna modules A1 to A N Each of them includes M antennas, which are respectively connected to the M drivers and the M resistors.

[0034] Furthermore, the N drive circuit modules U1 to U N The nth drive circuit module U n The m-th driver U in n,m The first terminal is connected to the N analog switch modules SW1 to SW2. N The nth analog switch module (i.e., the nth multi-select analog switch chip) SW n pin X of the mth generation m-1 The m-th driver U n,m The enable control terminal (low-level enable) and the N analog switch modules SW1 to SW N The (n+m)th analog switch module (i.e., the (n+m)th multi-select analog switch chip) SW n+m The enable pin is connected, and the m-th driver U n,m The second end is connected to the N antenna modules A1 to A N The nth antenna module A n The m-th antenna A n,m , where n is an integer greater than or equal to 1 and less than or equal to N, and m is an integer greater than or equal to 1 and less than or equal to M.

[0035] According to an embodiment of the present invention, the transmitting circuit module S1 includes an MCU chip, wherein its first pin I / O 0 to the N+M+3 pin I / O N+M+2 are configured in a strong push-pull mode to output control signals, and its N+M+4 pin I / O N+M+3 is configured in a strong push-pull mode when transmitting signals via the antenna to output a first transmit signal V1 (which is a pulse signal), and is configured in a high-impedance mode when receiving signals via the antenna to receive signals received via the antenna. The control signals include enable control signals CS0 to CS0. N+M-1 And select control signals C0, C1, and C2. Specifically, the first pin I / O 0 to the N+Mth pin I / O ON+M-1 are respectively connected to the first multi-select analog switch chip SW1 to the Nth multi-select analog switch chip SW1 in the N analog switch modules. N The enable pin (low-level enable) and / or the N drive circuit modules U1 to U N The corresponding driver's enable control terminal outputs an enable control signal CS0 to CS0. N+M-1 Pins N+M+1 (I / O N+M) to N+M+3 (I / O ON+M+2) are connected to the first multi-select analog switch chip SW1 to the Nth multi-select analog switch chip SW2. N The selection input pins are used to output selection control signals C0, C1, and C2.

[0036] Specifically, the configuration of the driver in the control circuit of the electromagnetic digitizing board according to the present invention will be described using an example where the control circuit of the electromagnetic digitizing board includes three analog switch modules (i.e., three multi-to-one analog switch chips SW1 to SW3), three drive circuit modules U1 to U3, and three antenna modules A1 to A3, and the analog switch modules are eight-to-one analog switch chips (e.g., 74HCT4051PW chips). Reference Figure 1 The transmitter circuit module (i.e., the MCU chip) S1 needs to be configured with at least pins I / O 0 to I / O 10 to output enable control signals CS0 to CS10. 10 The first driver U in the first drive circuit module U1 1,1 The first terminal is connected to the first pin X0 of the first 8-to-1 analog switch chip SW1, and the first driver U 1,1 The enable control terminal is connected to the enable pin of the second 8-to-1 analog switch chip SW2, and is also connected to the second pin I / O 1 of the MCU chip S1. The first driver U 1,1 The second end is connected to the first antenna ANT in the first antenna module A1. 1,1 And the first resistor R in the first drive circuit module U1 1,1 With the first driver U 1,1In a parallel connection, the enable pin of the first 8-to-1 analog switch chip SW1 is connected to the first pin I / O 0 of the MCU chip S1. Next, the second driver U in the first drive circuit module U1... 1,2 The first terminal is connected to the second pin X1 of the first 8-to-1 analog switch chip SW1, and the second driver U 1,2 The enable control terminal is connected to the enable pin of the third 8-to-1 analog switch chip SW3, and then connected to the third pin I / O 2 of the MCU chip S1. The second driver U 1,2 The second end is connected to the second antenna A in the first antenna module A1. 1,2 And the second resistor R in the first drive circuit module U1 1,2 With the second drive U 1,2 Parallel connection, and so on.

[0037] According to an embodiment of the present invention, the N driving circuit modules U1 to U N Each driver in the signal is connected to a power supply (which provides a constant voltage of +5V) and a ground terminal to be powered by the power supply and selectively output a second transmit signal V2, the voltage value of which corresponds to the high-level voltage value of the first transmit signal V1.

[0038] Now refer to Figures 1 to 2 The working principle of the driver in the control circuit of the electromagnetic digitizing board according to an embodiment of the present invention will be described in detail. Figure 2 An equivalent circuit diagram of the driver in the control circuit of an electromagnetic digitizing board according to an embodiment of the present invention is shown.

[0039] refer to Figure 2 When the antenna ANT 1,1 When transmitting signals, the antenna ANT 1,1 Connected driver U 1,1 The second transmit signal V2 is selectively output based on a high-level signal or a low-level signal received from the multi-select analog switch chip SW1. Specifically, according to an exemplary embodiment of the present invention, when the first transmit signal V1 is output from the MCU chip, the first transmit signal V1 (which is a pulse signal) is output through the corresponding multi-select analog switch chip SW1. When the signal received from the multi-select analog switch chip SW1 is a high-level signal, the driver U... 1,1 Powered by the power supply Vcc, a second transmission signal V2 is output, with a voltage value corresponding to the high-level voltage value of the first transmission signal V1, such as... Figure 3 , Figure 4A as well as Figure 4B As shown. Therefore, even if an additional analog switch chip SW1 has resistance, it will not affect the connection via the antenna ANT.1,1 The voltage of the transmitted signal is increased, thereby improving the power of the transmitted signal of the electromagnetic digitizing board compared to existing electromagnetic digitizing boards, and thus improving the signal-to-noise ratio of the corresponding received signal. Conversely, according to another exemplary embodiment of the present invention, when the signal received from the multi-select analog switch chip SW1 is a low-level signal, the driver U... 1,1 Powered by the power supply Vcc, a second transmission signal V2 is output, with a voltage value corresponding to the high-level voltage value of the first transmission signal V1, such as... Figure 5 As shown.

[0040] Now refer to Figures 1 to 3 The control process of the control circuit of the electromagnetic digitizing board according to an embodiment of the present invention will be described. Figure 3 A schematic diagram is shown of a control circuit for an electromagnetic digitizing tablet according to an exemplary embodiment of the present invention, in which the driver is a tri-state gate driver. The description continues with an example where the control circuit of the electromagnetic digitizing tablet includes three analog switch modules (i.e., three multi-to-one analog switch chips SW1 to SW3), three drive circuit modules U1 to U3, and three antenna modules A1 to A3, and the analog switch modules (i.e., multi-to-one analog switch chips) are eight-to-one analog switch chips (e.g., 74HCT4051PW chips).

[0041] Assuming the antenna ANT 1,1 Transmit and receive signals when the antenna ANT 1,1 When transmitting a signal, MCU chip S1 connects the first pin X0 of the first 8-to-1 analog switch chip SW1, which is used to output the first transmit signal V1, by setting the selection control signals C0, C1, and C2 output via pins 12 (I / O 11) to 14 (I / O 13). A low-level enable control signal CS0 is output to the enable pin of the first 8-to-1 analog switch chip SW1 via pin 1 (I / O 0), and a low-level enable control signal CS1 is output to the driver U via pin 2 (I / O 1). 1,1 The enable control terminal of the second 8-to-1 analog switch chip SW2, and the high-level enable control signal CS2 to CS1 is transmitted through the third pin I / O 2 to the eleventh pin I / O 10. 10 The outputs are respectively sent to the enable control terminals of other drivers and the enable pin of the third 8-to-1 analog switch chip SW3. In this case, since both the enable control terminals of the drivers and the enable pin of the multiplexer analog switch chip are low-level enabled, although the enable control signal CS1 of the enable pin of the second 8-to-1 analog switch chip SW2 is a low-level signal, the driver U connected to the second 8-to-1 analog switch chip SW2... 2,1 The enable control signal CS2 at the enable control terminal is a high-level signal, therefore the driver U2,1 It is in a high-impedance state. At this time, although the first pin X0 of the second 8-to-1 analog switch chip SW2 is connected to the first transmit signal V1, due to the resistor R... 2,1 The existence of the antenna ANT 2,1 The transmitted signal has low energy and will not affect the selectivity of the entire circuit. In other words, with the above configuration, the first transmitted signal V1 output by the MCU chip S1 is only transmitted through the driver U. 1,1 Switching to the second transmit signal V2 (whose voltage value corresponds to the high-level voltage value of the first transmit signal V1), thereby causing the second transmit signal V2 to be transmitted via the antenna ANT. 1,1 Transmit. In this way, the power of the transmitted signal is ensured to be unaffected by the resistors in the multiplexer analog switch chip.

[0042] When the antenna ANT 1,1 When receiving a signal, MCU chip S1 connects the first pin X0 of the first 8-to-1 analog switch chip SW1 for receiving signals by setting the selection control signals C0, C1, and C2 output via pins 12 (I / O 11) to 14 (I / O 13). It then outputs a low-level enable control signal CS0 to the enable pin of the first 8-to-1 analog switch chip SW1 via pin 1 (I / O 0), and outputs a high-level enable control signal CS1 to CS2 via pins 2 (I / O 1) to 11 (I / O 10). 10 The outputs are respectively sent to the enable control terminals of all drivers, as well as the enable pins of the second 8-to-1 analog switch chip SW2 and the third 8-to-1 analog switch chip SW3. In this case, driver U 1,1 It exhibits a high impedance state, but due to the presence of the driver U 1,1 Parallel resistors R 1,1 From the antenna ANT 1,1 The received signal passes through resistor R 1,1 The signal is transmitted to the first pin X0 of the first 8-to-1 analog switch chip SW1, and then input to the amplifier for amplification through the first 8-to-1 analog switch chip SW1, and then enters the subsequent processing circuit for processing.

[0043] Alternatively, Figure 3 The tri-state gate driver in the reference can also be implemented using equivalent discrete components. Figure 4A and Figure 4B Describe it. Figure 4A and Figure 4B A schematic diagram showing the driver as a discrete component in the control circuit of an electromagnetic digitizing board according to an exemplary embodiment of the present invention is shown.

[0044] like Figure 4A As shown, driver U 1,1This includes resistors R40, R41, R42, R43, and R44, diode D1, and transistors Q5, Q6, and Q7. The first terminals of resistors R40, R41, and R42 are connected to the first pin X0 to the Mth pin X of the multi-select analog switch chip. M-1 The corresponding pins in.

[0045] like Figure 4B As shown, driver U 1,1 This includes resistors R45, R46, and R47, diode D2, and transistors Q8 and Q9. The first terminals of resistors R45 and R46 are connected to the first pin X0 to the Mth pin X of the multi-select analog switch chip. M-1 The corresponding pins in.

[0046] Figure 5 A schematic diagram of a driver in the control circuit of an electromagnetic digitizing board according to another exemplary embodiment of the present invention is shown. According to this embodiment, when the signal received from the multiplexer analog switch chip is a low-level signal, the driver U... 1,1 Powered by the power supply Vcc, a second transmission signal V2 is output, with a voltage value corresponding to the high-level voltage value of the first transmission signal V1. For example... Figure 5 As shown, driver U 1,1 This includes resistors R50, R51, and R52, diodes D3 and D4, and MOSFET Q10. The first terminals of resistors R51 and R52 are connected to the first pin X0 to the Mth pin X of the multi-select analog switch chip. M-1 The corresponding pins in.

[0047] The control circuit of the electromagnetic digitizing board according to the above-described embodiment of the present invention adds a driver to each antenna of the electromagnetic digitizing board and connects a resistor in parallel across the driver. The input terminal of the driver is connected to the corresponding pin of a multi-select analog switch chip, the enable control terminal of the driver is connected to the enable pin of other multi-select analog switch chips, and the output terminal of the driver is connected to the corresponding antenna. This increases the power of the transmitted signal of the electromagnetic digitizing board, thereby improving the signal-to-noise ratio of the corresponding received signal. Furthermore, since the enable control signal of the multi-select analog switch chip is multiplexed, the number of pins required by the MCU chip is not increased, and minimal modifications are needed to the MCU chip software.

[0048] The foregoing description of specific exemplary embodiments of the invention is for illustrative and descriptive purposes. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed, and it will be apparent that various modifications and variations are possible in light of the foregoing teachings. The exemplary embodiments were chosen and described to explain the specific principles of the invention and its practical application, thereby enabling others skilled in the art to utilize and implement various exemplary embodiments of the invention, as well as various alternatives and modifications thereof. The scope of the invention is intended to be defined by the appended claims and their equivalents.

Claims

1. A control circuit for an electromagnetic digitizing tablet, used to increase the power of a signal transmitted via an antenna of the electromagnetic digitizing tablet, the control circuit comprising: The transmitting circuit module is configured to output a first transmitting signal and a control signal; N analog switch modules are electrically connected to the transmitting circuit module and configured such that when a signal is transmitted via the antenna, based on a control signal output by the transmitting circuit module, the port for outputting the first transmitted signal is turned on, thereby causing the first transmitted signal to be output via the selected port; N driving circuit modules, each electrically connected to a corresponding analog switch module among the N analog switch modules, are configured to: selectively output a second transmission signal based on the signal output by the corresponding analog switch module when a signal is transmitted via the antenna; and There are N antenna modules, each electrically connected to a corresponding drive circuit module among the N drive circuit modules, and configured such that when a signal is transmitted via the antenna, a second transmission signal output by the corresponding drive circuit module is transmitted. Each of the N analog switch modules includes a multi-select analog switch chip, and the multi-select analog switch chip includes a first pin X0 to an Mth pin X. M-1 And the switch common pin Y, Each of the N driving circuit modules includes M drivers and M resistors, wherein the M resistors are connected in parallel with the M drivers respectively, and are connected to the first pin X0 to the Mth pin X0 respectively. M-1 Connect accordingly.

2. The control circuit of the electromagnetic digitizing board according to claim 1, wherein, Each of the N antenna modules includes M antennas, which are respectively connected to the M drivers and the M resistors.

3. The control circuit of the electromagnetic digitizing board according to claim 2, wherein, The first terminal of the m-th driver in the n-th driver circuit module of the N driver circuit modules is connected to the m-th pin X of the n-th multi-select analog switch chip in the N analog switch modules. m-1 The enable control terminal of the m-th driver is connected to the enable pin of the (n+m)-th multi-select analog switch chip in the N analog switch modules, and the second terminal of the m-th driver is connected to the m-th antenna in the n-th antenna module of the N antenna modules, where n is an integer greater than or equal to 1 and less than or equal to N, and m is an integer greater than or equal to 1 and less than or equal to M.

4. The control circuit of the electromagnetic digitizing board according to claim 3, wherein, The transmitting circuit module includes an MCU chip, whose first pin I / O 0 to the N+M+3 pin I / O N+M+2 are configured in a strong push-pull mode to output control signals. The N+M+4 pin I / O N+M+3 is configured in a strong push-pull mode when transmitting signals via the antenna to output a first transmit signal, and is configured in a high-impedance mode when receiving signals via the antenna to receive signals received via the antenna. The control signals include an enable control signal and a selection control signal. The first pin I / O 0 to the N+M pin I / O N+M-1 are respectively connected to the enable pins of the first multi-select analog switch chip to the Nth multi-select analog switch chip in the N analog switch modules and / or the enable control terminals of the corresponding drivers in the N drive circuit modules, so as to output enable control signals. Pins N+M+1 (I / O pins N+M) to N+M+3 (I / O pins N+M+2) are connected to the selection input pins of the first to Nth multi-select analog switch chips to output selection control signals. The first transmitted signal is a pulse signal.

5. The control circuit of the electromagnetic digitizing board according to claim 4, wherein, Each of the M drivers is connected to a power supply and a ground terminal to be powered by the power supply and selectively outputs a second transmission signal, the voltage value of which corresponds to the high-level voltage value of the first transmission signal.

6. The control circuit of the electromagnetic digitizing board according to claim 5, wherein, Both the enable control terminal of the driver and the enable pin of the multi-select analog switch chip are enabled at a low level.

7. The control circuit of the electromagnetic digitizing board according to claim 6, wherein, When the antenna transmits a signal, the MCU chip outputs a low-level enable control signal via corresponding pins to the enable control terminal of the driver connected to the transmitting antenna, the enable pin of the multi-select analog switch chip connected to the transmitting antenna, and the enable pin of another multi-select analog switch chip connected to the enable control terminal of the driver connected to the transmitting antenna. It also outputs a high-level enable control signal to the enable control terminals of other drivers and the enable pins of other multi-select analog switch chips. When the antenna receives a signal, the MCU chip outputs a low-level enable control signal to the enable pin of the multi-select analog switch chip connected to the antenna receiving the signal via the corresponding pin, and outputs a high-level enable control signal to the enable pins of other multi-select analog switch chips and the enable control terminals of all drivers.

8. The control circuit of the electromagnetic digitizing board according to claim 7, wherein, When the antenna transmits a signal, the driver connected to the antenna transmitting the signal is configured to selectively output a second transmit signal based on a high-level signal or a low-level signal received from the multiplexer analog switch chip.

9. The control circuit of the electromagnetic digitizing board according to claim 7, wherein, When the antenna receives a signal, the signal received from the antenna is transmitted to the pin of the multiplexer analog switch chip via a resistor connected in parallel with the driver.

10. The control circuit of the electromagnetic digitizing board according to claim 1, wherein, The multiple-choice analog switch chip includes a 2-to-1 analog switch chip, a 4-to-1 analog switch chip, an 8-to-1 analog switch chip, and a 16-to-1 analog switch chip, and the driver includes a tri-state gate driver.

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