Key signal conversion circuit, drive-by-wire device and conversion device

Abstract

The utility model provides a key signal conversion circuit, a drive-by-wire device and a conversion device, and relates to the technical field of earphones, the circuit comprises a filtering module, an amplification module and a comparison module, the input end of the filtering module is connected with a function key module on a wired earphone, and the filtering module is used for filtering a received key analog signal; the output end of the filtering module is connected with the input end of the amplifying module, so that the amplifying module amplifies the filtered key analog signal; the output end of the amplification module is connected with the input end of the comparison module, so that the comparison module converts the amplified key analog signal into a key digital signal, and the output end of the comparison module is connected with a signal processing module of the wired earphone, so that the signal processing module performs key action detection based on the key digital signal. The key analog signal is converted through the key signal conversion circuit, so that the signal processing module can accurately detect the key action based on the key digital signal.

Description

Technical Field

[0001] The present application relates to the field of headphones, and in particular to a key signal conversion circuit, a wire control device and a conversion device. Background Art

[0002] Wired headphones are an electronic device widely used in daily life, entertainment, work and other occasions. They transmit sound to the ear through wires. There are three buttons on the wire control panel: volume up, volume down, and pause. The audio playback device needs to use the button detection circuit to determine the user's button operation.

[0003] There is a special signal generation chip on the wired headset's line control. Pressing the volume button will generate a high-frequency signal of about 3ms. The different signal frequencies are used to distinguish whether the volume is increased or decreased. The key detection circuit currently used for audio equipment line control amplifies the signal first, then filters it, and then compares and converts it into a digital square wave signal that can be recognized by the microcontroller. However, if the signal amplitude is small, the signal is amplified first and then filtered, which is easy to be submerged in the strong out-of-band noise, which may cause serious nonlinear distortion and generate a large number of intermodulation components that are difficult to filter out. Utility Model Content

[0004] The purpose of the present application is to provide a key signal conversion circuit, a wire control device and a conversion device to address the deficiencies in the above-mentioned prior art, so that the key analog signal can be converted by the key signal conversion circuit, so that the signal processing module can accurately detect the key action based on the key digital signal.

[0005] To achieve the above purpose, the technical solution adopted in the embodiment of the present application is as follows:

[0006] In the first aspect, an embodiment of the present application provides a key signal conversion circuit, which includes: a filtering module, an amplifying module and a comparing module, wherein the input end of the filtering module is connected to the function key module on the wired headset, and is used to filter the received key analog signal, and the output end of the filtering module is connected to the input end of the amplifying module, so that the amplifying module amplifies the filtered key analog signal; the output end of the amplifying module is connected to the input end of the comparing module, so that the comparing module converts the amplified key analog signal into a key digital signal, and the output end of the comparing module is connected to the signal processing module of the wired headset, so that the signal processing module performs key action detection based on the key digital signal.

[0007] In an optional embodiment, the amplification module includes: a first operational amplifier module and a second operational amplifier module, wherein the input end of the first operational amplifier module is connected to the output end of the filtering module, the output end of the first operational amplifier module is connected to the input end of the second operational amplifier module, and the output end of the second operational amplifier module is connected to the input end of the comparison module.

[0008] In an optional implementation, the first operational amplifier module includes: a first amplifier, a first resistor, and a first capacitor;

[0009] The reverse input terminal of the first amplifier is used as the input terminal of the first operational amplifier module to connect to the output terminal of the filter module, the output terminal of the first amplifier is used as the output terminal of the first operational amplifier module to connect to the input terminal of the second operational amplifier module, and the forward input terminal of the first amplifier is connected to a preset power supply;

[0010] The first resistor is connected in parallel with the first capacitor, and one end of the first resistor is connected to the inverting input end of the first amplifier, and the other end of the first resistor is connected to the output end of the first amplifier.

[0011] In an optional embodiment, the number of the second operational amplifier module is at least one, and at least one second operational amplifier module is connected in sequence, wherein the input end of the first second operational amplifier module is connected to the output end of the first operational amplifier module, and the output end of the last second operational amplifier module is connected to the input end of the comparison module.

[0012] In an optional implementation, the second operational amplifier module includes: a second amplifier, a second resistor, a second capacitor and a third resistor;

[0013] The inverting input terminal of the second amplifier is connected to the output terminal of the first operational amplifier module through the second resistor, the output terminal of the second amplifier is used as the output terminal of the second operational amplifier module to connect to the input terminal of the comparison module, and the positive input terminal of the second amplifier is connected to a preset power supply;

[0014] The third resistor is connected in parallel with the second capacitor, and one end of the third resistor is connected to the inverting input end of the second amplifier, and the other end of the third resistor is connected to the output end of the second amplifier.

[0015] In an optional implementation, the comparison module includes: a third amplifier, a fourth resistor and a fifth resistor;

[0016] The inverting input terminal of the third amplifier is connected to the output terminal of the amplification module as the input terminal of the comparison module, the output terminal of the third amplifier is connected to the signal processing module as the output terminal of the comparison module, and the positive input terminal of the third amplifier is connected to the preset power supply through the fourth resistor;

[0017] One end of the fifth resistor is connected to the positive input end of the third amplifier, and the other end of the fifth resistor is connected to the output end of the third amplifier.

[0018] In an optional embodiment, the filtering module includes: a sixth resistor, a third capacitor, and a fourth capacitor. One end of the sixth resistor serves as an input end of the filtering module and is used to connect to the function button module on the wired headset. The other end of the sixth resistor is connected to the input end of the amplification module through the fourth capacitor. The other end of the sixth resistor is also grounded through the third capacitor.

[0019] In a second aspect, an embodiment of the present application further provides a wire control device, which comprises at least: a function key module, a signal processing module and any key signal conversion circuit described in the first aspect above.

[0020] In an optional implementation, the function key module is arranged on a line control board, and the signal processing module and the key signal conversion circuit are arranged on an interface board;

[0021] Alternatively, the function key module, the key signal conversion circuit and the signal processing module are all arranged on a line control board.

[0022] In a third aspect, an embodiment of the present application further provides a conversion device, which is an interface board of a wired headset or an earphone adapter, and is provided with a signal processing module and a key signal conversion circuit as described in any one of the first aspects above.

[0023] The beneficial effects of this application are:

[0024] The embodiment of the present application provides a key signal conversion circuit, a wire control device and a conversion device. The key signal conversion circuit includes: a filtering module, an amplifying module and a comparing module. The input end of the filtering module is connected to the function key module on the wired headset for filtering the received key analog signal. The output end of the filtering module is connected to the input end of the amplifying module, so that the amplifying module amplifies the filtered key analog signal; the output end of the amplifying module is connected to the input end of the comparing module, so that the comparing module converts the amplified key analog signal into a key digital signal, and the output end of the comparing module is connected to the signal processing module of the wired headset, so that the signal processing module detects the key action based on the key digital signal. The key signal conversion circuit provided by the present application first filters the received key analog signal and then amplifies the filtered key analog signal, so that the waveform of the amplified key analog signal is cleaner and more stable, avoiding the situation of amplifying the key analog signal first and then filtering it, which produces serious nonlinear distortion. The key analog signal is converted by the key signal conversion circuit, so that the signal processing module can accurately detect the key action based on the key digital signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A schematic diagram of the structure of a key signal conversion circuit provided in an embodiment of the present application;

[0027] Figure 2 A structural schematic diagram of another key signal conversion circuit provided in an embodiment of the present application;

[0028] Figure 3 A structural schematic diagram of another key signal conversion circuit provided in an embodiment of the present application;

[0029] Figure 4 A schematic diagram of a filtered key simulation signal provided in an embodiment of the present application;

[0030] Figure 5 A schematic diagram of a key simulation signal after a first-stage amplification provided in an embodiment of the present application;

[0031] Figure 6 A schematic diagram of a key simulation signal after secondary amplification provided in an embodiment of the present application;

[0032] Figure 7A schematic diagram of a key simulation signal after three-stage amplification provided in an embodiment of the present application;

[0033] Figure 8 A schematic diagram of a key digital signal provided in an embodiment of the present application.

[0034] Explanation of main component symbols: 100-key signal conversion circuit; 200-function key module; 300-signal processing module; 110-filter module; 120-amplifier module; 121-first operational amplifier module; 122-second operational amplifier module; 1221-first second operational amplifier module; 1222-second second operational amplifier module; 130-comparison module; R1-first resistor; R2-second resistor; R3-third resistor; R4-fourth resistor; R5-fifth resistor; R6-sixth resistor; C1-first capacitor; C2-second capacitor; C3-third capacitor; C4-fourth capacitor; U1-first amplifier; U2-second amplifier; U3-third amplifier. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0036] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0037] In the description of the present application, it should be noted that if the terms "upper", "lower", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, or is the orientation or position relationship in which the product of the application is usually placed when used. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0038] In addition, the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0039] It should be noted that, in the absence of conflict, the features in the embodiments of the present application may be combined with each other.

[0040] The key signal conversion circuit 100 provided in the present application is specifically described below through multiple examples in conjunction with the accompanying drawings.

[0041] Figure 1 This is a schematic diagram of a key signal conversion circuit provided in an embodiment of the present application. Figure 1 As shown, the key signal conversion circuit 100 includes: a filtering module 110, an amplifying module 120 and a comparing module 130. The input end of the filtering module 110 is connected to the function key module 200 on the wired headset, and is used to filter the received key analog signal. The output end of the filtering module 110 is connected to the input end of the amplifying module 120, so that the amplifying module 120 amplifies the filtered analog signal; the output end of the amplifying module 120 is connected to the input end of the comparing module 130, so that the amplifying module 120 converts the amplified analog signal into a digital signal, and the output end of the comparing module 130 is connected to the signal processing module 300 of the wired headset, so that the signal processing module 300 performs key action detection based on the digital signal.

[0042] Among them, the key signal conversion circuit 100 can be set on a wired headset, or on a headset adapter. The wired headset is provided with a wire control panel, i.e., a microphone panel, and a function key module 200 is installed on the wire control panel. The function key module 200 has multiple function keys. For example, the function key module 200 of the wire control panel has a volume increase function key, a volume reduction function key, and a volume pause function key. When the function keys are operated differently (including pressing, holding, releasing, etc.), a control signal composed of two different frequencies will be output. For example, when the volume increase function key is pressed, a sine wave signal with an amplitude of 25mV, 2V bias, and 280KHz+175KHz will be output. When the volume reduction function key is pressed, a sine wave signal with an amplitude of 25mV, 2V bias, and 280KHz+144KHz will be output.

[0043] Among them, if the key signal conversion circuit 100 is set on the wired headset, the input end of the filter module 110 is directly connected to the function key module 200 on the wired headset; if the key signal conversion circuit 100 is set on the earphone adapter, the input end of the filter module 110 is connected to the function key module 200 on the wired headset connected to the earphone adapter through the earphone adapter.

[0044] Since the input end of the filter module 110 is connected to the function key module 200, the filter module 110 will receive the key simulation signal generated after the function key is pressed, that is, the sine wave signal, and filter the received key simulation signal to obtain the filtered key simulation signal. Since the output end of the filter module 110 is connected to the input end of the amplification module 120, the amplification module 120 can receive the filtered key simulation signal and amplify the filtered key simulation signal.

[0045] Since the output end of the amplification module 120 is connected to the input end of the comparison module 130, the comparison module 130 can receive the amplified key analog signal and convert the amplified key analog signal into a key digital signal, and then transmit the key digital signal to the signal processing module 300, so that the signal processing module 300 performs key action detection based on the key digital signal, that is, determines the target function key of the key analog signal currently generated.

[0046] In summary, the embodiment of the present application provides a key signal conversion circuit, which includes: a filtering module, an amplifying module and a comparing module, wherein the input end of the filtering module is connected to the function key module on the wired headset for filtering the received key analog signal, and the output end of the filtering module is connected to the input end of the amplifying module, so that the amplifying module amplifies the filtered key analog signal; the output end of the amplifying module is connected to the input end of the comparing module, so that the comparing module converts the amplified key analog signal into a key digital signal, and the output end of the comparing module is connected to the signal processing module of the wired headset, so that the signal processing module performs key action detection based on the key digital signal. The key signal conversion circuit provided by the present application first filters the received key analog signal, and then amplifies the filtered key analog signal, so that the waveform of the amplified key analog signal is cleaner and more stable, avoiding the situation where the key analog signal is amplified first and then filtered, resulting in serious nonlinear distortion, and converting the key analog signal through the key signal conversion circuit, so that the signal processing module can accurately detect the key action based on the key digital signal.

[0047] Based on the key signal conversion circuit shown in the above embodiment, the embodiment of the present application also provides another possible implementation method of the key signal conversion circuit. Figure 2 This is a schematic diagram of another key signal conversion circuit provided in an embodiment of the present application. Figure 2 As shown, the amplification module 120 includes: a first operational amplifier module 121 and a second operational amplifier module 122, wherein the input end of the first operational amplifier module 121 is connected to the output end of the filtering module 110, the output end of the first operational amplifier module 121 is connected to the input end of the second operational amplifier module 122, and the output end of the second operational amplifier module 122 is connected to the input end of the comparison module 130.

[0048] Among them, the key analog signal filtered by the filtering module 110 is firstly amplified by the first operational amplifier module 121, and then the key analog signal after the first-stage amplification is amplified by the second operational amplifier module 122. Through multi-stage amplification of the key analog signal, the waveform amplitude of the key analog signal becomes larger and easier to detect.

[0049] Optionally, the first operational amplifier module 121 includes: a first amplifier U1 , a first resistor R1 , and a first capacitor C1 .

[0050] The reverse input terminal V1- of the first amplifier U1 is used as the input terminal of the first operational amplifier module 121 to connect to the output terminal of the filter module 110, the output terminal V1out of the first amplifier U1 is used as the output terminal of the first operational amplifier module 121 to connect to the input terminal of the second operational amplifier module 122, and the positive input terminal V1+ of the first amplifier U1 is connected to a preset power supply.

[0051] The first resistor R1 is connected in parallel with the first capacitor C1 , and one end of the first resistor R1 is connected to the inverting input end of the first amplifier U1 , and the other end of the first resistor R1 is connected to the output end of the first amplifier U1 .

[0052] Specifically, in the first operational amplifier module 121, when there is no input of the key analog signal, that is, the function key module 200 is not pressed, then according to the operational amplifier virtual short circuit, it is obtained that: V1-=V1+=0.5VDD, that is, the reverse input terminal V1- and the positive input terminal V1+ of the first amplifier U1 are both equal to the DC bias voltage 0.5VDD provided by the preset power supply, wherein the DC bias voltage 0.5VDD is used to raise the waveform to avoid clipping distortion at the negative end of the key analog signal.

[0053] When a key analog signal is input, the first capacitor C1 short-circuits the key analog signal. Due to the high input impedance of the operational amplifier, the key analog signal will pass through the first resistor R1 and be connected to the output end of the first amplifier U1. The reverse input end of the first amplifier U1 is equivalent to an input open circuit.

[0054] For example, if the key simulation signal is Vin, we know from the virtual circuit that:

[0055] (V1out-V1-) / R1=(V1--Vin) / R6

[0056] Since the reverse input terminal V1- of the first amplifier U1 is equivalent to an input disconnection, V1-=0, it can be determined that the key analog signal output by the first stage amplification of the first operational amplifier module 121 is:

[0057] V1out=-Vin*R1 / R6+0.5VDD

[0058] Among them, since the input end of each operational amplifier module will bring additional parasitic capacitance when wiring on the PCB board, generally 10-20pF, the parasitic capacitance will increase the high-frequency gain of the operational amplifier of the operational amplifier module, thereby causing greater high-frequency noise at the output end and self-oscillation. Therefore, the first capacitor C1 is used to perform phase compensation for the input key analog signal, which can prevent the operational amplifier from self-oscillation and suppress high-frequency noise.

[0059] Optionally, there is at least one second op amp module 122, and at least one second op amp module 122 is connected in sequence, wherein the input end of the first second op amp module is connected to the output end of the first op amp module 121, and the output end of the last second op amp module is connected to the input end of the comparison module 130.

[0060] Among them, there is no limit to the number of second operational amplifier modules 122, all of which are used to perform secondary amplification on the key analog signal output by the first operational amplifier module 121. At least one second operational amplifier module 122 is connected in sequence, that is, the output end of one second operational amplifier module 122 is connected to the input end of another second operational amplifier module 122. The key analog signal is further amplified by multiple second operational amplifier modules 122, so that the waveform of the key digital signal converted by the comparison module 130 is clearer, which helps the signal processing module 300 to detect key actions based on the key digital signal.

[0061] Optionally, the second operational amplifier module 122 includes: a second amplifier U2, a second resistor R2, a second capacitor C2 and a third resistor R3;

[0062] The reverse input terminal of the second amplifier U2 is connected to the output terminal of the first operational amplifier module 121 through the second resistor R2, the output terminal of the second amplifier U2 is connected as the output terminal of the second operational amplifier module 122 to connect to the input terminal of the comparison module 130, and the forward input terminal of the second amplifier U2 is connected to a preset power supply;

[0063] The third resistor R3 is connected in parallel with the second capacitor C2 , and one end of the third resistor R3 is connected to the inverting input end of the second amplifier U2 , and the other end of the third resistor R3 is connected to the output end of the second amplifier U2 .

[0064] Specifically, the inverting input terminal of the second amplifier U2 of the second operational amplifier module 122 is V2-, and the forward input terminal V2+ of the second amplifier U2 is a DC bias voltage 0.5VDD provided by a preset power supply.

[0065] Due to the virtual short circuit of the op amp, the reverse input of the second amplifier U2 is equal to the forward input = 0.5VDD. If the output of the second amplifier U2 is V2out, the virtual short circuit of the op amp IR3 = IR2, we can conclude that:

[0066] (V2out-V2-) / R3=(V2--V1out) / R2

[0067] Among them, V2-=0.5VDD, V1out=-Vin*R1 / R6+0.5VDD.

[0068] Then the output of the output terminal of the second amplifier U2 is determined to be:

[0069] V2out=(0.5VDD-V1out)*(R3 / R2)+0.5VDD=Vin*(R1 / R6)*(R3 / R2)+0.5VDD

[0070] The second capacitor C2 has the same function as the first capacitor C1 and will not be described in detail herein.

[0071] If there are two second operational amplifier modules 122 in the key signal conversion circuit 100, the output of the first second operational amplifier module 1221 is obtained according to the above example, and the key simulation signal output by the first second operational amplifier module 1221 is input into the second second operational amplifier module 1222, and further amplified by the second second operational amplifier module 1222.

[0072] Specifically, each second operational amplifier module 122 includes: a second amplifier U2, a second resistor R2, a second capacitor C2 and a third resistor R3, and the connection method is consistent. In order to distinguish the second second operational amplifier module 1222 from the first second operational amplifier module 1221, the first second operational amplifier module 1221 is set to include: a second amplifier U2, a second resistor R2, a second capacitor C2 and a third resistor R3. Then, the output of the second operational amplifier module 122 obtained in the above example is determined to be the output of the first second operational amplifier module 1221, and the second second operational amplifier module 1222 is set to include: a fourth amplifier U4, a seventh resistor R7, a fifth capacitor C5 and an eighth resistor R8. Since the connection method within the second operational amplifier module 122 is consistent, it will not be repeated here.

[0073] The reverse input terminal of the fourth amplifier U4 of the second second operational amplifier module 1222 is determined to be V4-, and the forward input terminal V4+ of the fourth amplifier U4 is the DC bias voltage 0.5VDD provided by the preset power supply. Due to the virtual short circuit of the operational amplifier, it is known that the reverse input terminal input of the fourth amplifier U4 is equal to the forward input terminal of the fourth amplifier U4 = 0.5VDD.

[0074] If the output of the output terminal of the fourth amplifier U4 is V4out, according to the virtual interrupt of the operational amplifier, IR8=IR7, it can be concluded that:

[0075] (V4out-V4-) / R8=(V4--V2out) / R7

[0076] Among them, V4-=0.5VDD, V2out is the same as above.

[0077] Then the output of the output terminal of the fourth amplifier U4 is determined to be:

[0078] V4out=-Vin*(R1 / R6)*(R3 / R2)*(R8 / R7)+0.5VDD

[0079] The fifth capacitor C5 has the same function as the first capacitor C1 and will not be described in detail herein.

[0080] The embodiment of the present application also provides another possible implementation of the key signal conversion circuit. Figure 3 This is a structural diagram of another key signal conversion circuit provided in an embodiment of the present application. Figure 3As shown, the comparison module 130 includes: a third amplifier U3, a fourth resistor R4 and a fifth resistor R5.

[0081] The reverse input terminal of the third amplifier U3 is connected to the output terminal of the amplification module 120 as the input terminal of the comparison module 130, the output terminal of the third amplifier U3 is connected to the signal processing module 300 as the output terminal of the comparison module 130, and the forward input terminal of the third amplifier U3 is connected to the preset power supply through the fourth resistor R4.

[0082] One end of the fifth resistor R5 is connected to the positive input end of the third amplifier U3 , and the other end of the fifth resistor R5 is connected to the output end of the third amplifier U3 .

[0083] Specifically, the third amplifier U3 is an operational amplifier, used as a comparator, wherein, if the number of the second operational amplifier modules 122 is two, for example, the output V4out of the second second operational amplifier module 1222 is input to the input of the comparison module 130, the input signal of the reverse input terminal of the third amplifier U3 is V3-, and the forward input terminal of the third amplifier U3 is V3+. Due to the virtual short circuit of the operational amplifier, it is known that the reverse input terminal input of the third amplifier U3 is equal to the forward input terminal of the third amplifier U3.

[0084] If the output of the output terminal of the third amplifier U3 is V3out, according to the virtual interrupt of the operational amplifier, IR5=IR4, it can be concluded that:

[0085] (V3out-V3+) / R5=(V3+-iVDD) / R4

[0086] Among them, V3-=V4out, V3+=V3-.

[0087] Then the output of the output terminal of the third amplifier U3 is determined to be:

[0088] V3out=(V4out-iVDD)*(R5 / R4)+V4out

[0089] Among them, iVDD is a bias voltage determined by a preset power supply according to the average voltage of the key analog signal output by the amplification module 120. By controlling the two values ​​of iVDD and R5 / R4, when the output voltage exceeds the range of 0 to VDD, the key digital signal output by the comparison module 130 is a square wave with a peak value of VDD. The amplified key analog signal is converted into a key digital signal through the comparison module 130.

[0090] The embodiment of the present application also provides another possible implementation of the key signal conversion circuit. The filter module 110 includes: a sixth resistor R6, a third capacitor C3, and a fourth capacitor C4. One end of the sixth resistor R6 is used as an input end of the filter module 110 to connect to the function key module 200 on the wired headset, and the other end of the sixth resistor R6 is connected to the input end of the amplification module 120 through the fourth capacitor C4. The other end of the sixth resistor R6 is also grounded through the third capacitor C3.

[0091] Continue to refer Figure 3 The filter module 110 is an RC low-pass filter composed of a sixth resistor R6 and a third capacitor C3, and its cut-off frequency is F=1 / (2*π*R*C).

[0092] The function of the low-pass filter is mainly to suppress high-frequency signals and allow low-frequency signals to pass. Among them, the fourth capacitor C4 in the filter module 110 can be used as an AC coupling capacitor to isolate DC interference and pass high frequencies and block low frequencies. The filter module 110 is used to implement filtering of the key analog signal.

[0093] The embodiment of the present application also uses multiple example diagrams to illustrate the process of converting key analog signals by each module of the key signal conversion circuit 100. Figure 4 A schematic diagram of a filtered key simulation signal provided in an embodiment of the present application; Figure 5 A schematic diagram of a key simulation signal after a first-stage amplification provided in an embodiment of the present application; Figure 6 A schematic diagram of a key simulation signal after secondary amplification provided in an embodiment of the present application; Figure 7 A schematic diagram of a key simulation signal after three-stage amplification provided in an embodiment of the present application; Figure 8 A schematic diagram of a key digital signal provided in an embodiment of the present application.

[0094] Specifically, the input key simulation signal is filtered by the filter module 110 to suppress the high-frequency signal and allow the low-frequency signal to pass through to obtain the following Figure 4 The key simulation signal shown in FIG. 1 is then amplified by the first operational amplifier module 121 in the amplification module 120 to obtain the key simulation signal after filtering. Figure 5 As shown in the key simulation signal, if there are two second operational amplifier modules 122 in the amplification module 120, the key simulation signal after the primary amplification is amplified by the first second operational amplifier module to obtain the following Figure 6 The key analog signal shown in FIG. 1 is amplified by the second op amp module to obtain the key analog signal after the second stage amplification. Figure 7 The key analog signal shown in FIG. 1 is finally converted into a key digital signal by the comparison module 130 after the three-stage amplification. Figure 8The key digital signal shown is used to realize the conversion of key analog signal.

[0095] The embodiment of the present application further provides a possible implementation of a wire control device. The wire control device at least includes: a function key module 200 , a signal processing module 300 and a key signal conversion circuit 100 .

[0096] Optionally, the function key module 200 is arranged on a line control board, and the signal processing module 300 and the key signal conversion circuit 100 are arranged on an interface board.

[0097] Specifically, the wire control device is provided with a wire control board and an interface board, which are connected to the wire control board and the interface board through a wired connection. A function key module 200 is provided on the wire control board for sending a key analog signal to a key signal conversion circuit 100 on the interface board. The key analog signal is converted by the key signal conversion circuit 100 to obtain a key digital signal, and then the signal processing module 300 performs key action detection based on the key digital signal, wherein the interface board can be provided at an interface for connecting electronic devices.

[0098] Alternatively, the function key module 200, the key signal conversion circuit 100 and the signal processing module 300 are all arranged on a line control board.

[0099] Specifically, a function key module 200, a key signal conversion circuit 100 and a signal processing module 300 are arranged on the wire control board of the wire control device, and the conversion of the key analog signal is performed on the wire control board.

[0100] The embodiment of the present application also provides a possible implementation of a conversion device, which is an interface board of a wired headset or an earphone adapter, and is provided with a signal processing module 300 and a key signal conversion circuit 100.

[0101] The interface board of the wired headset or the headset adapter is provided with a signal processing module 300 and a key signal conversion circuit 100, and the conversion of the key analog signal is performed on the conversion device.

[0102] The embodiment of the present application also provides a possible implementation of a wired headset, the wired headset includes: a listening part and a wired control device, and the listening part is wiredly connected to the wired control device.

[0103] Among them, if the function button module 200 is set on the line control board, the signal processing module 300 and the button signal conversion circuit 100 are set on the interface board, then it is a currently common wired headset, the listening part, that is, the earpiece, is connected to the line control board, that is, the microphone board, through a wire, the function button module 200 and the microphone are set on the line control board, and then the wired headset interface is connected through a wire, and an interface board is set at the wired headset interface, and the interface board is provided with the signal processing module 300 and the button signal conversion circuit 100 for button analog signal conversion and button action detection.

[0104] If the function button module 200, the button signal conversion circuit 100 and the signal processing module 300 are all arranged on the online control board, it is a currently common wired Bluetooth headset. The listening part, i.e., the earpiece, is connected to the online control board, i.e., the microphone board, through a wire. The function button module 200 and the microphone are arranged on the online control board. The signal processing module 300 and the button signal conversion circuit 100 are also arranged for performing button analog signal conversion and button action detection on the online control board. The difference between the two is that the wired headset needs to be connected to the terminal device through an interface, while the wired Bluetooth headset can be connected to the terminal device wirelessly via Bluetooth.

[0105] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A key signal conversion circuit, characterized in that: The key signal conversion circuit includes: a filtering module, an amplifying module and a comparing module. The input end of the filtering module is connected to the function key module on the wired headset, and is used to filter the received key analog signal. The output end of the filtering module is connected to the input end of the amplifying module, so that the amplifying module amplifies the filtered key analog signal. The output end of the amplifying module is connected to the input end of the comparing module, so that the comparing module converts the amplified key analog signal into a key digital signal. The output end of the comparing module is connected to the signal processing module of the wired headset, so that the signal processing module performs key action detection based on the key digital signal. The amplification module includes: a first operational amplifier module and a second operational amplifier module, wherein the input end of the first operational amplifier module is connected to the output end of the filtering module, the output end of the first operational amplifier module is connected to the input end of the second operational amplifier module, and the output end of the second operational amplifier module is connected to the input end of the comparison module.

2. The circuit according to claim 1, characterized in that The first operational amplifier module includes: a first amplifier, a first resistor and a first capacitor; The reverse input terminal of the first amplifier is used as the input terminal of the first operational amplifier module to connect to the output terminal of the filter module, the output terminal of the first amplifier is used as the output terminal of the first operational amplifier module to connect to the input terminal of the second operational amplifier module, and the forward input terminal of the first amplifier is connected to a preset power supply; The first resistor is connected in parallel with the first capacitor, and one end of the first resistor is connected to the inverting input end of the first amplifier, and the other end of the first resistor is connected to the output end of the first amplifier.

3. The circuit according to claim 1, characterized in that The number of the second operational amplifier module is at least one, and the at least one second operational amplifier module is connected in sequence, wherein the input end of the first second operational amplifier module is connected to the output end of the first operational amplifier module, and the output end of the last second operational amplifier module is connected to the input end of the comparison module.

4. The circuit according to claim 1, characterized in that The second operational amplifier module includes: a second amplifier, a second resistor, a second capacitor and a third resistor; The inverting input terminal of the second amplifier is connected to the output terminal of the first operational amplifier module through the second resistor, the output terminal of the second amplifier is used as the output terminal of the second operational amplifier module to connect to the input terminal of the comparison module, and the positive input terminal of the second amplifier is connected to a preset power supply; The third resistor is connected in parallel with the second capacitor, and one end of the third resistor is connected to the inverting input end of the second amplifier, and the other end of the third resistor is connected to the output end of the second amplifier.

5. The circuit according to claim 1, characterized in that The comparison module includes: a third amplifier, a fourth resistor and a fifth resistor; The inverting input terminal of the third amplifier is connected to the output terminal of the amplification module as the input terminal of the comparison module, the output terminal of the third amplifier is connected to the signal processing module as the output terminal of the comparison module, and the positive input terminal of the third amplifier is connected to the preset power supply through the fourth resistor; One end of the fifth resistor is connected to the positive input end of the third amplifier, and the other end of the fifth resistor is connected to the output end of the third amplifier.

6. The circuit according to claim 1, characterized in that The filtering module includes: a sixth resistor, a third capacitor, and a fourth capacitor. One end of the sixth resistor serves as an input end of the filtering module and is used to connect to the function button module on the wired headset. The other end of the sixth resistor is connected to the input end of the amplification module through the fourth capacitor. The other end of the sixth resistor is also grounded through the third capacitor.

7. A wire control device, characterized in that: The wire control device at least comprises: a function key module, a signal processing module and the key signal conversion circuit described in any one of claims 1 to 6.

8. The wire control device according to claim 7, characterized in that: The function key module is arranged on the line control board, and the signal processing module and the key signal conversion circuit are arranged on the interface board; or, The function key module, the key signal conversion circuit and the signal processing module are all arranged on the line control board.

9. A conversion device, characterized in that: The conversion device is an interface board of a wired headset or an earphone adapter, and is provided with a signal processing module and the key signal conversion circuit described in any one of claims 1 to 6.

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