Disclosure of Invention
The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention needs to provide an earphone.
According to the invention, the earphone comprises a feedforward microphone, a feedforward filter unit and a noise reduction processing unit, wherein the feedforward microphone is used for collecting external noise of the earphone and forming an external noise signal, the feedforward microphone is used for collecting internal noise of the earphone and forming an internal noise signal, the feedforward filter unit is used for carrying out filter processing on the external noise signal, the feedforward filter unit is used for carrying out filter processing on the internal noise signal, and the noise reduction processing unit is used for carrying out noise reduction processing on the external noise signal subjected to filter processing and the internal noise signal subjected to filter processing.
Preferably, the feedforward filtering unit includes a first operational amplifying circuit, a first frequency response lifting circuit, a second frequency response lifting circuit, a first signal attenuation circuit and a third frequency response lifting circuit, where the first operational amplifying circuit is used for amplifying the collected external noise signal, the first frequency response lifting circuit is used for lifting the first frequency response of the amplified external noise signal, the second frequency response lifting circuit is used for lifting the second frequency response of the lifted external noise signal, the first signal attenuation circuit is used for attenuating the second lifted external noise signal, and the third frequency response lifting circuit is used for lifting the third frequency response of the attenuated external noise signal.
Preferably, the feedforward filter unit further includes a feedforward collection end MIC5, a resistor R128, a diode D24, a resistor R129, and a capacitor C101, where the feedforward collection end MIC5 is configured to receive the external noise signal collected by the feedforward microphone, a first end of the feedforward collection end MIC5 is connected with the resistor R128 and one end of the resistor R129, the diode D24 is connected with a first end of the feedforward collection end MIC5 and a second end of the feedforward collection end MIC5, a second end of the feedforward collection end MIC5 is grounded, another end of the resistor R129 is connected with the capacitor C101, and another end of the capacitor C101 is connected with the first operational amplifier circuit.
Preferably, the first frequency response boost circuit includes a low-pass filter circuit and a high-pass filter circuit, the low-pass filter circuit includes a resistor R92, a resistor R91 and a capacitor C62, the high-pass filter circuit includes a capacitor C73, a capacitor C72, a resistor R93 and a resistor R95, one end of the resistor R92 is connected to the output end of the transport amplifying circuit, the other end of the resistor R92 is simultaneously connected to the resistor R91 and one end of the capacitor C62, the other end of the capacitor C62 is grounded, one end of the capacitor C73 is connected to the output end of the transport amplifying circuit, the other end of the capacitor C73 is simultaneously connected to the capacitor C72 and one end of the resistor R93, the other end of the capacitor C72 is connected to the other end of the resistor R91, the other end of the resistor R93 is grounded, the resistor R91 and the other end of the capacitor C72 are both connected to one end of the resistor R95, and the other end of the resistor R95 is connected to the second frequency response boost circuit.
Preferably, the second frequency response boost circuit includes a resistor R100, a resistor R97, a resistor R96, a capacitor C74, a capacitor C77, a capacitor C76, a resistor R98 and a capacitor C78, wherein the other end of the resistor R95 is connected with one end of the resistor R100 and one end of the capacitor C78 at the same time, the other end of the resistor R100 is connected with one end of the resistor R97 and one end of the capacitor C77 at the same time, the other end of the resistor R97 is connected with one end of the resistor R96 and one end of the capacitor C74 at the same time, the other end of the capacitor C74 is grounded, the other end of the capacitor C77 is connected with one end of the capacitor C76 and one end of the resistor R98 at the same time, the other end of the capacitor C78 is connected with the resistor R96 and the other end of the capacitor C76, and the other end of the capacitor C78 is connected with the first signal attenuation circuit.
Preferably, the first signal attenuation circuit includes a resistor R25, a resistor R19, a capacitor C42, a capacitor C103, a capacitor C63, a resistor R33, and a resistor R87, wherein the other end of the capacitor C78 is connected to one end of the resistor R25 and one end of the capacitor C103, the other end of the resistor R25 is connected to one end of the resistor R19 and one end of the capacitor C42, the other end of the capacitor C42 is grounded, the other end of the capacitor C103 is connected to one end of the capacitor C63 and one end of the resistor R33, the other end of the resistor R33 is grounded, the other end of the capacitor C63 is connected to the other end of the resistor R19, the other end of the capacitor C63 is connected to one end of the resistor R87, and the other end of the resistor R87 is connected to the third frequency response boost circuit.
Preferably, the third frequency response boost circuit includes a resistor R88, a resistor R53, a resistor R1, a capacitor C27, a capacitor C108, a capacitor C105, a resistor R84, and a capacitor C60, wherein the other end of the resistor R87 is connected to one ends of the resistor R88 and the capacitor C60, the other end of the resistor R88 is connected to one ends of the resistor R53 and the capacitor C108, the other end of the resistor R53 is connected to one ends of the resistor R1 and the capacitor C27, the other end of the capacitor C27 is grounded, the other end of the capacitor C108 is connected to one ends of the capacitor C105 and the capacitor C84, the other end of the resistor R84 is grounded, and the other end of the capacitor C60 is connected to the other ends of the resistor R1 and the capacitor C105.
Preferably, the first frequency response lifting circuit is used for lifting the amplified external noise signal by 100-200Hz for the first time, the second frequency response lifting circuit is used for lifting the external noise signal by 100-200Hz for the second time, and the third frequency response lifting circuit is used for lifting the attenuated external noise signal by 100-200Hz for the third time.
Preferably, the feedback filtering unit includes a second operational amplifying circuit, a fourth frequency response lifting circuit, a fifth frequency response lifting circuit, a second signal attenuation circuit and an operational amplifier inverting circuit, where the second operational amplifying circuit is used for amplifying the collected internal noise signal, the fourth frequency response lifting circuit is used for lifting the first frequency response of the amplified internal noise signal, the fifth frequency response lifting circuit is used for lifting the second frequency response of the lifted internal noise signal, the second signal attenuation circuit is used for attenuating the second lifted internal noise signal, and the operational amplifier inverting circuit is used for inverting the operation amplifier of the attenuated internal noise signal.
Preferably, the feedback filtering unit further includes a feedback collecting end MIC4, a resistor R135, a diode D23, a resistor R136 and a capacitor C104, where the feedback collecting end MIC4 is configured to receive the internal noise signal collected by the feedback microphone, a first end of the feedback collecting end MIC4 is connected with the resistor R135 and one end of the resistor R136, the diode D23 is connected with the first end of the feedback collecting end MIC4 and a second end of the feedback collecting end MIC4, the second end of the feedback collecting end MIC4 is grounded, the other end of the resistor R136 is connected with the capacitor C104, and the other end of the capacitor C104 is connected with the second operational amplifying circuit.
According to the invention, the noise reduction performance of the earphone is improved due to the fact that the external noise and the internal noise of the earphone are restrained in a distinguishing way through the feedforward and the feedback design.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present invention and are not to be construed as limiting the present invention.
In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically connected, electrically connected or can be communicated with each other; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
In the present invention, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is less level than the second feature.
The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. In order to simplify the present disclosure, components and arrangements of specific examples are described below. They are, of course, merely examples and are not intended to limit the invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, which are for the purpose of brevity and clarity, and which do not themselves indicate the relationship between the various embodiments and/or arrangements discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the application of other processes and/or the use of other materials.
Referring to fig. 1, an earphone according to a preferred embodiment of the present invention includes a feedforward microphone 1, a feedforward microphone 2, a feedforward filter unit 3, a feedforward filter unit 4, and a noise reduction unit 5, wherein the feedforward microphone 1 is used for collecting external noise of the earphone and forming an external noise signal, the feedforward microphone 2 is used for collecting internal noise of the earphone and forming an internal noise signal, the feedforward filter unit 3 is used for filtering the external noise signal, the feedforward filter unit 4 is used for filtering the internal noise signal, and the noise reduction unit 5 is used for noise reduction of the filtered external noise signal and the filtered internal noise signal.
According to the invention, the noise reduction performance of the earphone is improved due to the fact that the external noise and the internal noise of the earphone are restrained in a distinguishing way through the feedforward and the feedback design.
In the present embodiment, the feedforward microphone 1, the feedforward microphone 2, the feedforward filter unit 3, the feedforward filter unit 4, and the noise reduction processing unit 5 constitute a noise reduction system, and the noise reduction systems are disposed on both left and right sides of the earphone.
The earphone of the present invention is a head cover earphone, and of course, the earphone of the present invention may be any other earphone, and is not limited to a head cover earphone.
Specifically, referring to fig. 2 and 3 in combination, for clarity of illustration, the circuit diagram of the feedforward filter unit 3 is split into fig. 2 and 3 at the UI end, the feedforward filter unit 3 includes a first operational amplifier circuit 31, a first frequency response boost circuit 32, a second frequency response boost circuit 33, a first signal attenuation circuit 34 and a third frequency response boost circuit 35, the first operational amplifier circuit 31 is used for performing operational amplification on the collected external noise signal, the first frequency response boost circuit 32 is used for performing first 100-200Hz frequency response boost on the amplified external noise signal, the second frequency response boost circuit 33 is used for performing second 100-200Hz frequency response boost on the boosted external noise signal, the first signal attenuation circuit 34 is used for attenuating the second boosted external noise signal, and the third frequency response boost circuit 35 is used for performing third 100-200Hz frequency response boost on the attenuated external noise signal.
In this embodiment, the feedforward filter unit 3 further includes a feedforward collection end MIC5, a resistor R128, a diode D24, a resistor R129, and a capacitor C101, where the feedforward collection end MIC5 is configured to receive an external noise signal collected by the feedforward microphone 1, a first end of the feedforward collection end MIC5 is connected to one end of the resistor R128 and one end of the resistor R129, the diode D24 is connected to the first end of the feedforward collection end MIC5 and a second end of the feedforward collection end MIC5, the second end of the feedforward collection end MIC5 is grounded, the other end of the resistor R129 is connected to the capacitor C101, and the other end of the capacitor C101 is connected to the first operational amplifier circuit 31.
In this embodiment, the first frequency response boost circuit 32 includes a low-pass filter circuit and a high-pass filter circuit, the low-pass filter circuit includes a resistor R92, a resistor R91, and a capacitor C62, the high-pass filter circuit includes a capacitor C73, a capacitor C72, a resistor R93, and a resistor R95, one end of the resistor R92 is connected to the output end of the transmission amplifying circuit, the other end of the resistor R92 is simultaneously connected to one end of the resistor R91 and one end of the capacitor C62, the other end of the capacitor C62 is grounded, one end of the capacitor C73 is connected to the output end of the transmission amplifying circuit, the other end of the capacitor C73 is simultaneously connected to one end of the capacitor C72 and one end of the resistor R93, the other end of the capacitor C72 is connected to the other end of the resistor R91, the other ends of the resistor R91 and the capacitor C72 are connected to one end of the resistor R95, and the other end of the resistor R95 is connected to the second frequency response boost circuit 33.
In this embodiment, the second frequency response boost circuit 33 includes a resistor R100, a resistor R97, a resistor R96, a capacitor C74, a capacitor C77, a capacitor C76, a resistor R98 and a capacitor C78, wherein the other end of the resistor R95 is connected to one end of the resistor R100 and one end of the capacitor C78 at the same time, the other end of the resistor R100 is connected to one end of the resistor R97 and one end of the capacitor C77 at the same time, the other end of the capacitor C74 is grounded, the other end of the capacitor C77 is connected to one end of the capacitor C76 and one end of the resistor R98 at the same time, the other end of the resistor R98 is grounded, the other end of the capacitor C78 is connected to the other ends of the resistor R96 and the capacitor C76, and the other end of the capacitor C78 is connected to the first signal attenuation circuit 34.
In the present embodiment, the first signal attenuation circuit 34 includes a resistor R25, a resistor R19, a capacitor C42, a capacitor C103, a capacitor C63, a resistor R33, and a resistor R87, the other end of the capacitor C78 is connected to one ends of the resistor R25 and the capacitor C103, the other end of the resistor R25 is connected to one ends of the resistor R19 and the capacitor C42, the other end of the capacitor C42 is grounded, the other end of the capacitor C103 is connected to one ends of the capacitor C63 and the resistor R33, the other end of the resistor R33 is grounded, the other end of the capacitor C63 is connected to the other end of the resistor R19, the other end of the capacitor C63 is connected to one end of the resistor R87, and the other end of the resistor R87 is connected to the third frequency response boost circuit 35.
In the present embodiment, the third frequency response boost circuit 35 includes a resistor R88, a resistor R53, a resistor R1, a capacitor C27, a capacitor C108, a capacitor C105, a resistor R84, and a capacitor C60, wherein the other end of the resistor R87 is connected to one ends of the resistor R88 and the capacitor C60, the other end of the resistor R88 is connected to one ends of the resistor R53 and the capacitor C108, the other end of the resistor R53 is connected to one ends of the resistor R1 and the capacitor C27, the other end of the capacitor C27 is grounded, the other end of the capacitor C108 is connected to one ends of the capacitor C105 and the resistor R84, the other end of the resistor R84 is grounded, and the other end of the capacitor C60 is connected to the other ends of the resistor R1 and the capacitor C105.
In this way, the feedforward filter unit 3 filters the external environmental sound of the earphone, thereby suppressing the external noise.
Referring to fig. 4 and 5 in combination, for clarity, the feedback filter unit 4 splits fig. 4 and 5 at the ui end, and the feedback filter unit 4 includes a second operational amplifier circuit 41, a fourth frequency response boost circuit 42, a fifth frequency response boost circuit 43, a second signal attenuation circuit 44, and an operational amplifier inverting circuit 45, where the second operational amplifier circuit 41 is used for amplifying the collected internal noise signal, the fourth frequency response boost circuit 42 is used for boosting the amplified internal noise signal by a first frequency response of 100-200Hz, the fifth frequency response boost circuit 43 is used for boosting the boosted internal noise signal by a second frequency response of 100-200Hz, the second signal attenuation circuit 44 is used for attenuating the second boosted internal noise signal, and the operational amplifier inverting circuit 45 is used for amplifying and inverting the attenuated internal noise signal.
In this embodiment, the feedback filter unit 4 further includes a feedback collection end MIC4, a resistor R135, a diode D23, a resistor R136, and a capacitor C104, where the feedback collection end MIC4 is configured to receive the internal noise signal collected by the feedback microphone 2, a first end of the feedback collection end MIC4 is connected to one end of the resistor R135 and one end of the resistor R136, the diode D23 is connected to the first end of the feedback collection end MIC4 and a second end of the feedback collection end MIC4, the second end of the feedback collection end MIC4 is grounded, the other end of the resistor R136 is connected to the capacitor C104, and the other end of the capacitor C104 is connected to the second operational amplifier circuit 41.
In this embodiment, the fourth frequency response boost circuit 42 includes a resistor R120, a resistor R119, a capacitor C92, a capacitor C96, a capacitor C95, a resistor R121, a resistor R117, a resistor R116, a capacitor C91, a capacitor C94, a capacitor C93, a resistor R122, a resistor R13, a resistor R14, and a capacitor C33, the output end of the second transport amplifying circuit is connected to one end of the resistor R120 and the capacitor C96, the other end of the resistor R120 is connected to one end of the resistor R119 and the capacitor C92, the other end of the capacitor C92 is grounded, the other end of the capacitor C96 is connected to one end of the resistor C95 and one end of the resistor R121, the other end of the resistor C95 is grounded, the other end of the capacitor C95 is connected to one end of the resistor R117 and one end of the capacitor C94, the other end of the resistor R117 is connected to one end of the resistor R116 and one end of the capacitor C91, the other end of the capacitor C94 is grounded, the other end of the capacitor C94 is connected to one end of the capacitor C93 and one end of the resistor R122, the other end of the resistor R122 is grounded, the other end of the capacitor C93 is connected to the other end of the resistor C13 and the other end of the resistor C33 is connected to one end of the resistor R13 and the resistor R33, and the other end of the resistor R13 is connected to the other end of the resistor R13.
In this embodiment, the fifth frequency response boost circuit 43 includes a resistor R127, a resistor R125, a resistor R124, a capacitor C97, a capacitor C99, a capacitor C98, a resistor R126, and a capacitor C100, wherein the other end of the capacitor C33 is connected to one ends of the resistor R127 and the capacitor C100, the other end of the resistor R127 is connected to one ends of the resistor R125 and the capacitor C99, the other end of the resistor R125 is connected to one ends of the resistor R124 and the capacitor C97, the other end of the capacitor C97 is grounded, the other end of the capacitor C99 is connected to one ends of the capacitor C98 and the resistor R126, the other end of the capacitor C100 is connected to the other ends of the resistor R124 and the capacitor C98, and the other end of the capacitor C100 is connected to the second signal attenuation circuit 44.
In this embodiment, the second signal attenuation circuit 44 includes a resistor R18, a resistor R155, a capacitor C88, a capacitor C110, a capacitor C109, a resistor R24, and a resistor R110, the other end of the capacitor C100 is connected to one ends of the resistor R18 and the capacitor C110, the other end of the resistor R18 is connected to one ends of the resistor R16 and the capacitor C88, the other end of the capacitor C88 is grounded, the other end of the capacitor C110 is connected to one ends of the capacitor C109 and the resistor R24, the other end of the resistor R24 is grounded, the other end of the capacitor C109 is connected to the other end of the resistor R16, the other end of the capacitor C109 is connected to one end of the resistor R110, and the other end of the resistor R110 is connected to the op amp inverter circuit 45.
In the present embodiment, the operational amplifier inverting circuit 45 includes a resistor R111 and a capacitor C89, and the other end of the resistor R110 is connected to one end of the resistor R111 and one end of the capacitor C89, and the other end of the resistor R111 is connected to the other end of the capacitor C89.
In this way, the feedback filtering unit 4 filters the environmental sound inside the earphone, so as to suppress the noise inside the earphone.
In this embodiment, the earphone further includes an input sound source signal unit 6 connected to the noise reduction processing unit 5, the input sound source signal unit 6 for inputting a sound source signal to the noise reduction processing unit 5, and a speaker 7 for outputting the noise-reduced sound source signal.
In this way, the sounds picked up by the feedforward microphone 1 and the feedforward microphone 2 are combined with the feedforward filter unit 3, the feedforward filter unit 4 and the input sound source signal unit 6, so as to complete the noise reduction processing of the active feedforward and the feedforward and output the driving loudspeaker 7.
In summary, the feedforward collection end MIC5 collects the external noise signal, and enters the first operational amplifier circuit through the resistor R129 and the capacitor C101, so as to obtain a low-pass and high-pass filter circuit composed of the resistor R92, the resistor R91, the capacitor C62, the capacitor C73, the capacitor C72, the resistor R93 and the resistor R95, namely the first frequency response boost circuit 32, to boost the frequency response of 100-200Hz for the first time; the boosted external noise signal passes through an operational amplifier feedback type filter network formed by a resistor R100, a resistor R97, a resistor R96, a capacitor C74, a capacitor C77, a capacitor C76, a resistor R98 and a capacitor C78, namely a second frequency response boosting circuit 33, and the second 100-200Hz frequency response is boosted; the boosted external noise signal is attenuated by the first signal attenuation circuit 34 through the resistor R25, the resistor R19, the capacitor C42, the capacitor C103, the capacitor C63, the resistor R33 and the resistor R87, and finally the earphone is driven after the third frequency response is boosted by the operational amplifier feedback filter network formed by the resistor R88, the resistor R53, the resistor R1, the capacitor C27, the capacitor C108, the capacitor C105, the resistor R84 and the capacitor C60, namely the third frequency response boost circuit 35. Therefore, the external noise signal is counteracted with the external noise after being inverted, so that the purpose of actively reducing noise is achieved.
The internal noise signals of the earphone are collected by the feedback collection end MIC4 and enter a second operational amplifier circuit through a resistor R136 and a capacitor C104 to obtain the low-pass and high-pass filter circuits which are formed by the resistor R120, the resistor R119, the capacitor C92, the capacitor C96, the capacitor C95, the resistor R121, the resistor R117, the resistor R116, the capacitor C91, the capacitor C94, the capacitor C93, the resistor R122, the resistor R13, the resistor R14 and the capacitor C33 and are used for carrying out the first 100-200Hz frequency response promotion through a fourth frequency response promotion circuit 42; the boosted internal noise signal is boosted for the second time by the operational amplifier feedback type filter network formed by the resistor R127, the resistor R125, the resistor R124, the capacitor C97, the capacitor C99, the capacitor C98, the resistor R126 and the capacitor C100, namely the fifth frequency response boosting circuit 43; the raised internal noise signal is attenuated by the second signal attenuation circuit 44 through the resistor R18, the resistor R155, the capacitor C88, the capacitor C110, the capacitor C109, the resistor R24 and the resistor R110, and finally the earphone is driven after passing through the operational amplifier inverting circuit 45 formed by the resistor R111 and the capacitor C89. Therefore, the internal noise signals are counteracted with the internal noise of the earphone after being inverted, so that the purpose of actively reducing noise is achieved.
Referring to fig. 4, it can be seen from the noise reduction curves in the figure that the noise reduction effect is more ideal by the superposition of the active noise reduction of the feedforward and the feedback, and is clearer when listening to music when no sound source signal is input as in the silent world.
In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the invention, the scope of which is defined by the claims and their equivalents.