Noise reduction method, apparatus, device, medium, and program product for satellite phones

Abstract

The application relates to a noise reduction method, device, equipment, medium and program product for a satellite telephone, the method comprising guiding original ambient sound to a noise reduction cavity for wind noise pre-attenuation to obtain wind noise attenuated sound; picking up a first sound signal from the wind noise attenuated sound through a first microphone and picking up a second sound signal from the wind noise attenuated sound through a second microphone; after setting a sending loudness level through a bias resistor network in a differential input circuit, converting the first sound signal and the second sound signal into a first differential signal and a second differential signal through a single-end-to-differential conversion structure respectively, and transmitting the first differential signal and the second differential signal to a noise reduction chip through a differential signal line; and generating a noise reduction digital voice signal by adaptively canceling the first digital audio stream according to the second digital audio stream through the noise reduction chip. The application can meet the high-reliability call demand of the satellite telephone under the conditions of vibration and strong radio frequency interference.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite phones, and in particular to a noise reduction method, apparatus, device, medium and program product. Background Technology

[0002] Satellite phones operate at high frequencies, with their radio frequency (RF) and audio modules located very close together. Furthermore, call environments are often outdoors, characterized by high wind speeds, strong mechanical vibrations, and wideband background noise. Existing consumer-grade active noise cancellation solutions primarily target low-to-mid-frequency steady-state noise, offering limited effectiveness in suppressing the energy-dispersed wideband non-steady-state noise present in satellite phone applications. Simultaneously, the high transmission power of satellite phones makes it easy for RF harmonics to couple to the high-gain analog front-end, generating audible interference and affecting the stability of the noise cancellation algorithm. These combined issues make it difficult for existing solutions to simultaneously achieve wideband noise suppression, RF interference immunity, and high reliability in the complex electromagnetic and acoustic environments of satellite phones. Summary of the Invention

[0003] The main objective of this invention is to provide a noise reduction method, apparatus, device, medium, and program product for satellite phones that can preserve voice components in complex background noise environments and meet the high reliability call requirements of satellite phones under vibration and strong radio frequency interference conditions.

[0004] To achieve the above objectives, the present invention provides a noise reduction method for satellite phones, comprising: The original ambient sound is guided to the noise reduction cavity for wind noise pre-attenuation, resulting in wind noise attenuated sound. A first sound signal is picked up from the wind noise attenuation sound using a first microphone, and a second sound signal is picked up from the wind noise attenuation sound using a second microphone. The first sound signal and the second sound signal are converted into first differential signal and second differential signal respectively by the differential input circuit and transmitted to the noise reduction chip. The noise reduction chip converts the first differential signal and the second differential signal into a first digital audio stream and a second digital audio stream, respectively. The noise reduction chip performs adaptive noise cancellation on the first digital audio stream based on the second digital audio stream to generate a noise-reduced digital speech signal.

[0005] Furthermore, the step of guiding the original ambient sound to the noise reduction cavity for wind noise pre-attenuation to obtain wind noise-attenuated sound includes: The noise reduction cavity includes a sound intake component and a coupling cavity; The original ambient sound is allowed to enter the cavity of the sound inlet component through the sound inlet hole, and is initially buffered and slowed down to obtain a slowed-down sound. The decelerating sound enters the coupling cavity through the through hole of the sound inlet component and the sound inlet hole of the coupling cavity; The wind noise of the deceleration sound is selectively absorbed by the loose porous sound-absorbing medium inside the coupling cavity, thereby obtaining the wind noise attenuated sound.

[0006] Further, the step of picking up the first sound signal from the wind noise attenuation sound using the first microphone and the second sound signal from the wind noise attenuation sound using the second microphone includes: A first sound signal containing speech and residual environmental noise is picked up from the wind noise attenuation sound using the first microphone; The second microphone is used to pick up a second sound signal containing residual environmental noise from the wind noise attenuation sound; Both the first microphone and the second microphone are omnidirectional microphones, and in the call state, the RMS power value of the signal received by the first microphone is 6dB greater than the RMS power value of the signal received by the second microphone, and the frequency response curves of the first microphone and the second microphone are parallel to each other.

[0007] Further, the step of converting the first audio signal and the second audio signal into first differential signals and second differential signals respectively through a differential input circuit and transmitting them to the noise reduction chip includes: The bias resistor network in the differential input circuit provides DC bias for the first microphone and the second microphone, and the transmit loudness level of the first microphone and the second microphone is configured by adjusting the resistance value of the bias resistor network; The first sound signal and the second sound signal obtained after setting the transmission loudness level are converted into differential form of the first differential signal and the second differential signal through the single-ended to differential structure of the differential input circuit; During the transmission of the first differential signal and the second differential signal to the noise reduction chip via the differential signal line of the differential input circuit, transmission line reflection and ringing are suppressed by the source impedance matching resistor connected in series on the differential signal line, and radio frequency interference is filtered out by the decoupling capacitor connected in parallel to the input of the differential signal line.

[0008] Further, the step of converting the first differential signal and the second differential signal into a first digital audio stream and a second digital audio stream respectively through the noise reduction chip includes: The first differential signal is converted into a first digital audio stream by the first differential analog-to-digital converter built into the noise reduction chip; The second differential signal is converted into a second digital audio stream by the second differential analog-to-digital converter built into the noise reduction chip; The differential analog-to-digital converter has a sampling accuracy of 16 bits, a sampling frequency of 8kHz, and a peak input voltage of 2.4V.

[0009] Furthermore, it also includes: During the noise reduction process performed by the noise reduction chip, the level states of the volume adjustment pin and the mute control pin of the noise reduction chip are monitored in parallel. When the volume adjustment pin is detected to be in a high-level state, the output volume is adjusted accordingly after the minimum duration. If it is detected that the volume adjustment pin remains at a high level after the minimum duration, then four volume adjustment steps are executed continuously within one second until the volume adjustment pin is no longer at a high level. When the mute input pin is detected to be high, the system switches between mute mode and non-mute mode and outputs the current mute status indication through the mute output pin.

[0010] The present invention also provides a noise reduction cavity for a satellite phone, applied to any one of the noise reduction methods for satellite phones described above, comprising: The sound-inlet component has a sound inlet hole at its open end and multiple through holes at its closed end. The coupling cavity is formed by sealing the front shell and the rear shell. One side of the coupling cavity is provided with a sound inlet hole that communicates with the first through hole, and the other side is provided with multiple sound outlet holes. The sound outlet holes are used to communicate with the pickup surface of the microphone unit. The through holes and the sound outlet holes are arranged alternately in spatial position; The coupling cavity is filled with a loose, porous sound-absorbing medium.

[0011] The present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the noise reduction method for satellite telephone described in any of the preceding claims.

[0012] The present invention also provides a readable storage medium storing a computer program that, when executed by a processor, implements the steps of the noise reduction method for satellite phones described above.

[0013] The present invention also provides a computer program product comprising a computer program that, when executed by a processor, implements the steps of the noise reduction method for satellite phones described above.

[0014] The present invention provides a noise reduction method, apparatus, device, medium, and program product for satellite phones, which has the following beneficial effects: By guiding the original ambient sound into the noise reduction cavity for wind noise pre-attenuation, wind noise-attenuated sound is obtained. Then, the first and second microphones respectively pick up the sound signals containing speech and residual noise, effectively attenuating broadband wind noise energy during the microphone pickup stage and reducing the noise suppression pressure of subsequent digital noise reduction processing. A differential input circuit converts the first and second sound signals into differential signals and transmits them to the noise reduction chip. Utilizing the common-mode rejection capability of differential transmission and impedance matching and decoupling measures on the transmission path, interference generated by RF harmonic coupling of the satellite communication module is effectively suppressed, ensuring the integrity of the audio front-end signal. The noise reduction chip converts the first and second differential signals into a first and a second digital audio stream, respectively. Using the second digital audio stream as a noise reference, adaptive noise cancellation is performed on the first digital audio stream, preserving speech components in complex background noise environments and generating a noise-reduced digital voice signal that meets the high-reliability call requirements of satellite phones under vibration and strong RF interference conditions. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of a noise reduction system for satellite phones according to an embodiment of the present invention; Figure 2 This is a flowchart illustrating a noise reduction method for satellite phones according to an embodiment of the present invention; Figure 3 This is a flowchart illustrating a noise reduction method for satellite phones according to an embodiment of the present invention; Figure 4 This is a circuit structure diagram of a dual-microphone signal input circuit according to an embodiment of the present invention; Figure 5 This is a circuit structure diagram of an analog interface circuit according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of a noise reduction cavity in a noise reduction method for satellite phones according to an embodiment of the present invention; Figure 7 This is a schematic diagram of a noise reduction device for satellite phones according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the structure of a computer device according to an embodiment of the present invention.

[0017] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. It should also be understood that, as used in this specification and the appended claims, the term "and / or" refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0020] Furthermore, in the description of this invention and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0021] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of the invention include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0022] It should be understood that the sequence number of each step in the following embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0023] To illustrate the technical solution of the present invention, specific embodiments are described below.

[0024] Satellite phones operate at high frequencies, with their radio frequency (RF) and audio modules located very close together. Furthermore, call environments are often outdoor scenarios characterized by high wind speeds, strong mechanical vibrations, and wideband background noise. Existing consumer-grade active noise cancellation solutions primarily target mid-to-low frequency steady-state noise, offering limited effectiveness in suppressing the wideband non-steady-state noise that disperses energy in satellite phone applications. Simultaneously, the high transmission power of satellite phones makes it easy for RF harmonics to couple to the high-gain analog front-end, generating audible interference and affecting the stability of the noise cancellation algorithm. These issues collectively make it difficult for existing solutions to simultaneously achieve wideband noise suppression, RF interference immunity, and high reliability in the complex electromagnetic and acoustic environments of satellite phones. To address the aforementioned issues, this application proposes a noise reduction method, apparatus, device, medium, and program product for satellite phones. By guiding the original ambient sound to a noise reduction cavity for wind noise pre-attenuation to obtain wind noise-attenuated sound, and then using a first microphone and a second microphone to pick up sound signals containing speech and residual noise respectively, broadband wind noise energy is effectively attenuated during the microphone pickup stage, reducing the noise suppression pressure of subsequent digital noise reduction processing. A differential input circuit converts the first and second sound signals into differential signals and transmits them to a noise reduction chip. Utilizing the common-mode rejection capability of differential transmission and impedance matching and decoupling measures on the transmission path, interference generated by radio frequency harmonic coupling of the satellite communication module is effectively suppressed, ensuring the integrity of the audio front-end signal. The noise reduction chip converts the first and second differential signals into a first and a second digital audio stream respectively, and uses the second digital audio stream as a noise reference to adaptively cancel noise in the first digital audio stream. This preserves speech components in complex background noise environments, generating a noise-reduced digital speech signal that meets the high-reliability call requirements of satellite phones under vibration and strong radio frequency interference conditions.

[0025] The noise reduction method for satellite phones provided in this invention can be applied to, for example... Figure 1 The noise reduction system for satellite phones shown includes a terminal device and a noise reduction apparatus for the satellite phone, wherein the terminal device communicates with a server via a network or bus.

[0026] The noise reduction device used in satellite phones can be a terminal device, which refers to a device that corresponds to a server and provides local services to customers. This terminal device includes, but is not limited to, various personal computers, laptops, smartphones, tablets, and portable wearable devices.

[0027] The noise reduction device used for satellite phones can also be a server, which can be a standalone server or a server cluster composed of multiple servers.

[0028] like Figure 2As shown, the present invention provides a noise reduction method for satellite phones, comprising: Step S100: Guide the original ambient sound to the noise reduction cavity for wind noise pre-attenuation to obtain wind noise attenuated sound; Specifically, the original ambient sound enters the cavity of the sound-inlet component through its inlet port for initial buffering and deceleration. After deceleration, the sound enters the coupling cavity through multiple through-holes at the closed end of the sound-inlet component and the inlet port of the coupling cavity. Inside the coupling cavity, the staggered arrangement of the through-holes in the sound-inlet component and the outlet port of the coupling cavity forces the airflow carried by the sound to deflect multiple times, thus attenuating wind noise energy. The loose, porous sound-absorbing medium filling the coupling cavity selectively absorbs the mid-to-high frequency wind noise components. The attenuated and absorbed sound then reaches the microphone's pickup surface through the outlet port of the coupling cavity, obtaining the wind noise-attenuated sound after pre-attenuation. This process significantly weakens strong wind noise before the sound-to-electric conversion, reducing the noise suppression load on subsequent circuits and algorithms.

[0029] Step S200: Pick up a first sound signal from the wind noise attenuation sound using a first microphone, and pick up a second sound signal from the wind noise attenuation sound using a second microphone; Specifically, the first microphone is positioned near the mouth of the satellite phone and pointed towards the user's mouth, picking up a first sound signal containing the user's voice and residual environmental noise from the wind noise attenuation sound. The second microphone is positioned away from the mouth, on the back or upper edge of the satellite phone, picking up a second sound signal primarily composed of residual environmental noise from the same wind noise attenuation sound. Both the first and second microphones are omnidirectional, and during a call, the RMS power value of the signal received by the first microphone is at least 6 dB higher than that of the signal received by the second microphone. Their frequency response curves are parallel to each other to ensure the accuracy of the noise reference signal and the noise reduction effect during subsequent adaptive noise cancellation.

[0030] Step S300: The first sound signal and the second sound signal are converted into a first differential signal and a second differential signal respectively through the differential input circuit and transmitted to the noise reduction chip; Specifically, the first and second audio signals are respectively input to the differential input circuit. The bias resistor network in the differential input circuit provides DC bias for the first and second microphones, and the transmission loudness level of the first and second microphones is configured by adjusting the resistance value of the bias resistor network. After the transmission loudness level is set, the first and second audio signals are converted into differential signals in the form of first differential signals and second differential signals respectively by the single-ended to differential structure of the differential input circuit. During the transmission of the first and second differential signals to the noise reduction chip through the differential signal line of the differential input circuit, the source impedance matching resistor connected in series on the differential signal line suppresses transmission line reflection and ringing, and the decoupling capacitor connected in parallel to the input end of the differential signal line filters out the radio frequency interference coupled by the satellite communication module, so as to obtain the interference-suppressed differential signal and send it to the noise reduction chip.

[0031] Step S400: The noise reduction chip converts the first differential signal and the second differential signal into a first digital audio stream and a second digital audio stream, respectively. Specifically, the first differential signal is input to the first differential analog-to-digital converter built into the noise reduction chip, and the second differential signal is input to the second differential analog-to-digital converter built into the noise reduction chip. Both the first and second differential analog-to-digital converters perform synchronous analog-to-digital conversion on the input differential signals at an 8kHz sampling frequency and 16-bit sampling precision, and output the first digital audio stream and the second digital audio stream, respectively, to provide time-domain aligned noise reference and noisy speech data for subsequent digital noise reduction processing.

[0032] Step S500: The noise reduction chip performs adaptive noise cancellation on the first digital audio stream according to the second digital audio stream to generate a noise-reduced digital voice signal.

[0033] Specifically, the first and second digital audio streams are input to the digital signal processor inside the noise reduction chip, where the digital signal processor executes the noise reduction algorithm code stored in the internal memory. Using the second digital audio stream as a noise reference signal, the noise component in the first digital audio stream is estimated through an adaptive filter, and the estimated noise component is subtracted from the first digital audio stream to obtain the noise-reduced digital speech signal. During the execution of the noise reduction algorithm by the digital signal processor, the core computing part is powered by an analog power supply independent of the digital power supply, and a crystal oscillator provides a stable clock reference to ensure reliable operation of the noise reduction processing under wide temperature and vibration conditions.

[0034] This application provides a noise reduction method for satellite phones. The method involves guiding the original ambient sound into a noise reduction cavity for wind noise pre-attenuation to obtain wind noise-attenuated sound. Then, a first microphone and a second microphone respectively pick up the sound signals containing speech and residual noise. This effectively attenuates broadband wind noise energy during the microphone pickup stage, reducing the noise suppression pressure of subsequent digital noise reduction processing. A differential input circuit converts the first and second sound signals into differential signals and transmits them to a noise reduction chip. Utilizing the common-mode rejection capability of differential transmission and impedance matching and decoupling measures on the transmission path, interference generated by radio frequency harmonic coupling in the satellite communication module is effectively suppressed, ensuring the integrity of the audio front-end signal. The noise reduction chip converts the first and second differential signals into a first digital audio stream and a second digital audio stream, respectively. Using the second digital audio stream as a noise reference, adaptive noise cancellation is performed on the first digital audio stream. This method can preserve speech components in complex background noise environments, generating a noise-reduced digital speech signal that meets the high-reliability call requirements of satellite phones under vibration and strong radio frequency interference conditions.

[0035] In one embodiment, the original ambient sound is guided to a noise reduction cavity for wind noise pre-attenuation to obtain wind noise-attenuated sound, including: The noise reduction cavity includes a sound intake component and a coupling cavity; The original ambient sound is allowed to enter the cavity of the sound inlet component through the sound inlet hole, and is initially buffered and slowed down to obtain a slowed-down sound. Specifically, the original ambient sound enters the internal cavity of the sound inlet component through the sound inlet hole at the open end of the sound inlet component under the action of external sound pressure. The space inside the cavity of the sound inlet component is relatively small and the sound wave transmission path is not straight. The airflow carried by the sound wave is constrained by space and its speed is reduced. The wind noise energy is initially attenuated due to the deceleration of the airflow. The sound wave after this processing is output as decelerated sound from multiple through holes at the closed end of the sound inlet component.

[0036] The decelerating sound enters the coupling cavity through the through hole of the sound inlet component and the sound inlet hole of the coupling cavity; Specifically, the decelerated sound outputs from the through-hole of the sound inlet component and then enters the sealed cavity inside the coupling cavity through the sound inlet hole on one side of the coupling cavity. The sound inlet hole of the coupling cavity is connected to the through-hole of the sound inlet component to ensure that the decelerated sound is completely introduced into the coupling cavity.

[0037] The wind noise of the deceleration sound is selectively absorbed by the loose porous sound-absorbing medium inside the coupling cavity, thereby obtaining the wind noise attenuated sound.

[0038] Specifically, the decelerated sound entering the coupling cavity is forced to undergo multiple deflections due to the misaligned spatial arrangement of the sound inlet holes and the sound outlet holes of the coupling cavity, and the wind noise energy is further dissipated during the deflection process.

[0039] Meanwhile, the loose, porous sound-absorbing medium filling the coupling cavity selectively absorbs mid-to-high frequency wind noise components, while having a relatively small absorption effect on low-frequency human voice components. The sound wave, after being processed by both attenuation and absorption by the sound-absorbing medium, reaches the microphone's pickup surface through the sound outlet of the coupling cavity, forming wind noise-attenuated sound, providing a significantly weakened acoustic input for subsequent dual-microphone pickup.

[0040] The method provided in this embodiment buffers and decelerates the original ambient sound within the noise reduction cavity, performing multiple reversals to pre-attenuate wind noise energy before acoustic-to-electrical conversion, thus reducing the noise suppression pressure of subsequent noise reduction processing. Utilizing a staggered through-hole layout and selective absorption by the sound-absorbing medium, broadband non-steady-state wind noise components are effectively suppressed, while low-frequency speech information is preserved. The wind noise-attenuated sound input to the microphone pickup surface after pre-attenuation provides the dual-microphone noise reduction with reduced wind noise, improving speech clarity in high-wind-speed outdoor environments.

[0041] In one embodiment, picking up a first sound signal from the wind noise attenuation sound using a first microphone and picking up a second sound signal from the wind noise attenuation sound using a second microphone includes: A first sound signal containing speech and residual environmental noise is picked up from the wind noise attenuation sound using the first microphone; The second microphone is used to pick up a second sound signal containing residual environmental noise from the wind noise attenuation sound; Specifically, a first microphone is mounted on the bottom front of the satellite phone, near the user's mouth, with its pickup direction facing the user's mouth. It picks up a first sound signal from the wind noise attenuation sound obtained in step S100, which simultaneously contains speech components and residual environmental noise components. A second microphone is mounted on the top edge of the back of the satellite phone, away from the user's mouth and with its pickup direction opposite to the user. It picks up a second sound signal from the same wind noise attenuation sound, with residual environmental noise as its main component.

[0042] During the pickup process, the first microphone, being closer to the user's mouth and directionally towards the speech source, exhibits a significantly stronger response to speech components than the second microphone, while its response to ambient noise components is roughly equivalent to that of the second microphone. By pre-calibrating the positions of the first and second microphones, the RMS power value of the signal received by the first microphone during a call is ensured to be 6 dB greater than that of the signal received by the second microphone, and their frequency response curves remain parallel within the effective speech frequency range. The acquired first and second audio signals serve as input sources for subsequent differential conversion steps, providing spatially separated noisy speech reference and pure noise reference for adaptive noise cancellation.

[0043] Both the first microphone and the second microphone are omnidirectional microphones, and in the call state, the RMS power value of the signal received by the first microphone is 6dB greater than the RMS power value of the signal received by the second microphone, and the frequency response curves of the first microphone and the second microphone are parallel to each other.

[0044] The first microphone is an omnidirectional microphone positioned near the mouth of the satellite phone and pointing towards the user's mouth. It is used to pick up a first sound signal containing the user's voice and residual ambient noise. The second microphone is an omnidirectional microphone positioned on the back or upper edge of the far end of the satellite phone, away from the user's mouth. It is used to pick up a second sound signal, primarily composed of residual ambient noise. An omnidirectional microphone is a sound-to-electrical transducer with consistent pickup sensitivity to sounds from different directions. Both the first and second microphones use this type to ensure consistent ambient noise pickup characteristics.

[0045] RMS power refers to the effective power of the audio signal. During a call, the RMS power of the signal received by the first microphone is at least 6 dB higher than that received by the second microphone. This difference characterizes the significant advantage of the first microphone in picking up speech components compared to the second microphone. Parallel frequency response curves indicate that the sensitivity changes of the first and second microphones at different frequencies are basically consistent, ensuring the spectral matching accuracy of the two signals during subsequent adaptive noise cancellation.

[0046] The method provided in this embodiment extracts a first sound signal dominated by speech and a second sound signal dominated by residual noise from the wind noise attenuation sound, respectively, to provide spatially separated noisy speech reference and pure noise reference for subsequent adaptive noise cancellation. By limiting the RMS power value of the signal received by the first microphone to be greater than that of the signal received by the second microphone by 6 dB, the method ensures that the speech component dominates in the first sound signal, thereby improving the correlation between the noise reference signal and the noise component in the noisy speech signal. By keeping the frequency response curves of the first and second microphones parallel to each other, the two signals are made consistent in spectral characteristics, improving the accuracy of noise component estimation during adaptive noise cancellation, thus effectively preserving speech components in complex background noise environments.

[0047] like Figure 3-4 As shown, in one embodiment, step S300, which involves converting the first audio signal and the second audio signal into first differential signals and second differential signals respectively via a differential input circuit and transmitting them to the noise reduction chip, includes: Step S310: The bias resistor network in the differential input circuit provides DC bias for the first microphone and the second microphone, and the transmit loudness level of the first microphone and the second microphone is configured by adjusting the resistance value of the bias resistor network; The differential input circuit refers to the signal conditioning circuit located between the microphone and the noise reduction chip, including a bias resistor network, a single-ended to differential structure, impedance matching resistors, and decoupling capacitors. The bias resistor network is a combination of resistors connected between the microphone's bias voltage terminal and ground, used to provide a stable DC operating point for the microphone. The transmit loudness level refers to the electrical signal strength of the microphone output signal under rated sound pressure level excitation; its value directly affects the balance between speech loudness and signal-to-noise ratio.

[0048] In this embodiment, the bias resistor network of the first microphone channel consists of a first resistor and a second resistor branch. The first resistor is connected between the microphone bias voltage terminal and the first microphone output terminal, and the second resistor branch is connected between the first microphone output terminal and ground. The second microphone channel adopts a symmetrical structure, and its bias resistor network consists of a first resistor and a second resistor branch. The first resistor is connected between the microphone bias voltage terminal and the second microphone output terminal, and the second resistor branch is connected between the second microphone output terminal and ground.

[0049] Specifically, as shown in the table below, the measured transmission loudness level and the correspondence between idle channel noise are as follows: under different total resistance configurations of the first and second resistor branches:

[0050] The first and second microphones are respectively connected to the corresponding input channels of the differential input circuit. By changing the total resistance of the second resistor branch, the sensitivity of the microphones can be adjusted, thereby affecting the transmitted loudness level. The four cases in the table above are analyzed separately: Scenario 1: The first resistor is 1kΩ, the total resistance of the second resistor branch is 1kΩ, the measured transmit loudness level is 16.40dB, and the idle channel noise is -69.78dB. This configuration provides a moderate transmit loudness level and can be used as a basic reference configuration.

[0051] Scenario 2: The first resistor is 330Ω, the total resistance of the second resistor branch is 2kΩ, the measured transmit loudness level is 10.97dB, and the idle channel noise is -69.56dB. Compared to Scenario 1, the first resistor is reduced, the total resistance of the second resistor branch is increased, and the transmit loudness level decreases.

[0052] Case 3: The first resistor is 330Ω, and the total resistance of the second resistor branch is 3kΩ. The measured transmit loudness level is 17.10dB, and the idle channel noise is -69.34dB. Compared to Case 2, the first resistor remains unchanged, and the total resistance of the second resistor branch is further increased. The transmit loudness level increases from 10.97dB to 17.10dB, indicating that increasing the total resistance of the second resistor branch connected between the microphone output and ground can effectively improve the transmit loudness level.

[0053] Scenario 4: The first resistor is 2kΩ, and the total resistance of the second resistor branch is 330Ω. The measured loudness level is 25.63dB, and the idle channel noise is -69.90dB. Compared to Scenario 3, the first resistor is significantly increased, while the total resistance of the second resistor branch is significantly decreased. Although the loudness level is still high, the reduced total resistance of the second resistor branch leads to a decrease in the microphone output signal amplitude. Additional amplification gain needs to be added to the signal link to compensate for the amplitude loss, which introduces more noise and affects sound quality.

[0054] Based on the test data from the above four scenarios, this embodiment preferably configures the first resistor to 330Ω and the total resistance of the second resistor branch to 3kΩ (i.e., scenario 3). At this time, the transmission loudness level is 17.10dB and the idle channel noise is -69.34dB, achieving a better balance between transmission loudness and signal-to-noise ratio, and meeting the requirements of satellite phone calls for both loudness and noise indicators.

[0055] Furthermore, the differential input circuit was compared with single-ended and pseudo-differential input circuits. Compared to single-ended and pseudo-differential input designs, the differential design exhibits stronger TDMA noise suppression and superior EMC performance. The pseudo-differential design offers better TDMA noise suppression than the single-ended design, but still falls short of the differential design, and its EMC performance is affected. The single-ended design carries a significant risk of TDMA noise, has more stringent wiring requirements, and suffers from poor EMC performance. Therefore, this embodiment employs a fully differential input architecture to ensure signal transmission quality in the high-RF environment of satellite phones.

[0056] Step S320: The first sound signal and the second sound signal obtained after setting the transmission loudness level are converted into differential form of the first differential signal and the second differential signal through the single-ended to differential structure of the differential input circuit; Specifically, the first sound signal and the second sound signal, output by the first microphone and the second microphone respectively after the loudness level is set, are converted into differential signals in the form of the first differential signal and the second differential signal through the single-ended to differential structure of the differential input circuit. The single-ended to differential structure refers to a circuit unit that converts a single-ended signal into a differential signal pair with opposite phase and equal amplitude, and is composed of a resistor network and a capacitor network.

[0057] After adjustment by the bias resistor network, the first and second microphones have reached the target loudness level. The first and second sound signals, respectively picked up and output by the microphones, enter their corresponding single-ended to differential converters. Within the single-ended to differential converter, the single-ended sound signal is converted into two symmetrical differential signals (positive and negative) through resistor voltage division and capacitor coupling, resulting in the first and second differential signals. The positive and negative differential signals have equal amplitudes and a 180-degree phase difference, providing natural suppression of external common-mode interference.

[0058] After differential conversion, the first and second differential signals are transmitted to the input of the differential analog-to-digital converter of the noise reduction chip via differential signal lines. The differential signal lines employ an equal-length, tightly coupled wiring design, with the characteristic impedance of the signal lines matched to the resistance value of the source-end impedance matching resistor. The source-end impedance matching resistor is connected in series at the end of the differential signal line closest to the signal source to suppress signal reflection and ringing caused by impedance discontinuities in the transmission lines.

[0059] A decoupling capacitor is connected in parallel at the input of the differential signal line to bypass and filter the radio frequency harmonics radiated from the satellite communication module onto the signal line, reducing the impact of radio frequency interference on the analog front end of the noise reduction chip. The first and second differential signals, after differential conversion and transmission path processing, are sent to the noise reduction chip for subsequent analog-to-digital conversion.

[0060] Step S330: During the transmission of the first differential signal and the second differential signal to the noise reduction chip via the differential signal line of the differential input circuit, the transmission line reflection and ringing are suppressed by the source impedance matching resistor connected in series on the differential signal line, and radio frequency interference is filtered out by the decoupling capacitor connected in parallel to the input end of the differential signal line.

[0061] In this context, a differential signal line refers to two copper foil traces of equal length and tightly coupled on a printed circuit board that carry the first and second differential signals. A source impedance matching resistor is a resistor connected in series with the differential signal line near the signal source end. Its resistance value matches the characteristic impedance of the differential signal line, absorbing reflected energy at the end of the transmission line and eliminating overshoot and ringing during high-speed signal switching.

[0062] A decoupling capacitor is a capacitor element connected in parallel between the input terminal of a differential signal line and the reference ground, used to provide a low-impedance discharge path for high-frequency radio frequency interference.

[0063] Specifically, the first differential signal and the second differential signal are transmitted from the differential input circuit to the noise reduction chip through their respective differential signal lines. Each differential signal line is connected in series with a source impedance matching resistor whose resistance value has been calculated in advance. The source impedance matching resistor absorbs the reflected energy generated at the point of impedance discontinuity of the transmission line during the rising and falling edges of the signal, so as to keep the signal waveform intact and avoid timing jitter and amplitude distortion caused by the superposition of reflected signals.

[0064] The decoupling capacitor connected in parallel between the differential signal line input and ground bypasses and attenuates the radio frequency harmonics coupled into the satellite communication module. The radio frequency interference signal flows into the reference ground through the low impedance path of the capacitor instead of entering the analog input of the noise reduction chip, thereby ensuring that the analog-to-digital converter inside the noise reduction chip accurately samples the pure differential signal.

[0065] The method provided in this embodiment provides DC bias to the first and second microphones through the bias resistor network in the differential input circuit and adjusts the resistance value to set the transmission loudness level, thereby optimizing the loudness and signal-to-noise ratio of the microphone output signal. This reduces the pressure of subsequent noise suppression while ensuring speech intelligibility. A single-ended to differential structure converts the first and second audio signals into differential signals, effectively suppressing common-mode interference caused by the coupling of radio frequency harmonics from the satellite communication module on the transmission line by utilizing the common-mode rejection characteristics of the differential signal pair. A source-end impedance matching resistor connected in series on the differential signal line suppresses transmission line reflections and ringing, and a parallel decoupling capacitor bypasses and filters radio frequency interference, ensuring the integrity and purity of the differential signal received by the noise reduction chip and improving the anti-interference capability and operational reliability of the audio front-end in complex electromagnetic environments.

[0066] like Figure 5As shown, in one embodiment, an analog interface circuit for the noise reduction chip FM1188 is also included. This circuit serves as an auxiliary audio interface in addition to the dual-microphone input channel, used to connect to an external analog audio source or output processed audio signals for debugging and testing. This analog interface circuit is independent of the dual-microphone differential input channel described in step S300 above. The two share some hardware resources within the noise reduction chip, but their signal flows are different.

[0067] The pseudo-interface circuit includes the input section of the ADC module and the output section of the DAC module.

[0068] In the ADC module input section, the external analog audio signal is input through the LINE_IN port and converted into differential signal pairs LINE_IN_P and LINE_IN_N by a single-ended to differential network composed of resistors R29 and R31 and capacitors C27 and C28, which are then connected to the noise reduction chip FM1188. This single-ended to differential conversion is similar in circuit structure to the single-ended to differential conversion of the microphone signal described in step S320, both converting single-ended signals into differential signal pairs with opposite phases and equal amplitudes to suppress common-mode interference. However, they serve the microphone input channel and the line input channel respectively, and their signal sources are independent of each other. When the differential analog signal is transmitted in the printed circuit board circuit, to suppress signal reflection and ringing caused by the discontinuity of the transmission line impedance, resistor R30 is connected in series on the LINE_IN_P signal line, and resistor R32 is connected in series on the LINE_IN_N signal line as source impedance matching resistors. The source impedance matching function of resistors R30 and R32 is the same as that of the source impedance matching resistors on the microphone differential signal line described in step S330; both are used to absorb reflected energy at the end of the transmission line and ensure signal waveform integrity. Capacitors C28 and C29 are decoupling capacitors configured according to power integrity calculations, used to filter out power ripple and high-frequency interference, and are functionally consistent with the decoupling capacitors connected in parallel at the input end of the microphone differential signal line in step S330.

[0069] The LINE_IN differential signal, after single-ended to differential conversion and impedance matching, enters the third differential analog-to-digital converter (ADC) inside the FM1188 noise reduction chip. This third ADC, along with the first ADC used to convert the first differential signal and the second ADC used to convert the second differential signal described in step S400, are all three differential ADCs built into the FM1188 chip, performing analog-to-digital conversion at an 8kHz sampling frequency and 16-bit sampling precision. The converted digital signal is sent to the DSP for digital signal processing, including FIR digital filtering and FFT transformation. The processed signal can be output by the DAC module or participate in other audio processing flows as needed. It should be noted that the signal input to the LINE_IN channel is not a reference signal for adaptive noise cancellation; its signal flow is independent of the adaptive noise cancellation main noise reduction process described in claim 1.

[0070] In the DAC module output section, the digital signal processed by the DSP is converted into an analog signal by the digital-to-analog converter embedded in the noise reduction chip and output through the LINE_OUT port. The LINE_OUT port can be used as a test port to facilitate circuit debugging and comparison with the signal from the speaker output port SPK_OUT. The remaining resistors and capacitors in the circuit are used for signal filtering.

[0071] Through the aforementioned analog interface circuit, the FM1188 noise reduction chip, in addition to supporting dual-microphone differential input for adaptive noise cancellation, also has independent line audio input and output capabilities, expanding the audio access flexibility of the satellite phone noise reduction system and facilitating system debugging and external audio source access.

[0072] In one embodiment, step S400, which involves converting the first differential signal and the second differential signal into a first digital audio stream and a second digital audio stream respectively using the noise reduction chip, includes: The first differential signal is converted into a first digital audio stream by the first differential analog-to-digital converter built into the noise reduction chip; Specifically, the first differential analog-to-digital converter samples the first differential signal at equal intervals at a sampling frequency of 8kHz. The analog voltage value obtained from each sampling is quantized into a 16-bit binary digital code to form a continuous first digital audio stream.

[0073] The second differential signal is converted into a second digital audio stream by the second differential analog-to-digital converter built into the noise reduction chip; Specifically, the second differential analog-to-digital converter samples and quantizes the second differential signal in 16 bits at the same 8kHz sampling frequency to generate the second digital audio stream. The sampling clocks of the two differential analog-to-digital converters are derived from the same crystal oscillator frequency divider signal, ensuring that the first and second digital audio streams are strictly aligned in time, providing time-domain synchronization reference data for subsequent adaptive noise cancellation.

[0074] The differential analog-to-digital converter has a sampling accuracy of 16 bits, a sampling frequency of 8kHz, and a peak input voltage of 2.4V.

[0075] The noise reduction chip uses the Fudi Audio FM1188 chip, which integrates three differential analog-to-digital converters (ADCs) and two digital-to-analog converters (DACs). The first differential ADC refers to the ADC unit within the noise reduction chip that receives the first differential signal, and the second differential ADC refers to the ADC unit within the noise reduction chip that receives the second differential signal; both are differential input types. Sampling precision refers to the number of bits used by the ADC to quantize the analog signal; in this embodiment, the sampling precision is 16 bits. Sampling frequency refers to the number of times the ADC samples the analog signal per second; in this embodiment, the sampling frequency is 8kHz. Peak input voltage refers to the maximum voltage amplitude of the differential input signal that the ADC can accept; in this embodiment, it is 2.4V.

[0076] The method provided in this embodiment converts the first differential signal and the second differential signal into a second digital audio stream and a second digital audio stream respectively through the first differential analog-to-digital converter and the second differential analog-to-digital converter built into the noise reduction chip. This achieves synchronous sampling and time-domain alignment of the two signals, providing precise matching reference data for adaptive noise cancellation. The differential input characteristics of the differential analog-to-digital converter further suppress residual common-mode interference in the transmission path, improving the anti-RF crosstalk capability of the analog-to-digital conversion stage. By configuring the sampling accuracy and sampling frequency to adapt to the requirements of voice signal processing and maintaining linear quantization within the peak input voltage range, signal clipping distortion is prevented, ensuring that the noise reduction chip stably completes analog-to-digital conversion under wide temperature and power fluctuation conditions.

[0077] In one embodiment, it also includes: During the noise reduction process performed by the noise reduction chip, the level states of the volume adjustment pin and the mute control pin of the noise reduction chip are monitored in parallel. The volume control pins include a volume up pin and a volume down pin, both of which are level-triggered and active high. A high level on the volume up pin increases the output volume, and a high level on the volume down pin decreases the output volume. The mute control pins include a mute input pin and a mute output pin. The mute input pin is active high and is used to switch between mute and non-mute modes. The mute output pin outputs a high level as a status indicator in mute mode.

[0078] Specifically, parallel monitoring refers to the process where, while the digital signal processor inside the noise reduction chip performs adaptive noise cancellation calculations, the input / output control module polls the voltage levels of the aforementioned pins at preset time intervals, records the current voltage level, and compares it with the voltage level of the previous cycle to identify rising edge events. This monitoring process does not interrupt the main noise reduction processing flow. After the noise reduction chip is powered on and reset, the input / output control module initializes the default state of each pin to low level and continuously detects voltage level changes to respond to user operations.

[0079] When the volume adjustment pin is detected to be in a high-level state, the output volume is adjusted accordingly after the minimum duration. The minimum duration of action refers to the shortest time required from the moment the volume adjustment pin goes high until the chip determines that the high level is a valid trigger; the minimum duration is 80ms. Adjusting the output volume means that when the volume increase pin is high, the output volume increases; when the volume decrease pin is high, the output volume decreases.

[0080] Specifically, once the input / output control module detects a rising edge on the volume up or volume down pin and maintains a high level, it starts an internal timer. If the high level lasts for 80ms, it is considered a valid single trigger event. The digital signal processor adjusts the gain coefficient of the output digital audio signal according to the adjustment direction corresponding to the trigger pin, completing one step of volume adjustment. If the high level disappears during the 80ms countdown, the trigger is discarded, and no volume adjustment operation is performed. The volume adjustment step size and minimum volume limit after each valid trigger are pre-programmed into the internal registers via the SHI bus interface to adapt to the different requirements of volume adjustment granularity and volume range in different application scenarios.

[0081] If it is detected that the volume adjustment pin remains at a high level after the minimum duration, then four volume adjustment steps are executed continuously within one second until the volume adjustment pin is no longer at a high level. Specifically, once the input / output control module determines that the high-level duration of the volume up or volume down pin has exceeded the minimum duration of 80ms and the first single-step volume adjustment has been completed, it continues to monitor the pin's level. If the high-level signal on the pin remains unchanged without returning to a low level, the input / output control module initiates a continuous adjustment timing sequence. Within the subsequent 1-second time window, it sequentially sends four volume adjustment commands to the digital signal processor at equal time intervals, each command corresponding to a single-step volume adjustment in the same direction as the first adjustment.

[0082] During continuous adjustment, the input / output control module continuously monitors the pin level. Once the pin level returns to low, it immediately terminates any unexecuted volume adjustment steps and ends the current continuous adjustment operation. By setting an upper limit for the number of continuous adjustment steps and a total duration constraint, volume loss due to abnormally high pin levels or button malfunctions is avoided, ensuring the reliability of the volume adjustment process and the consistency of the user experience.

[0083] When the mute input pin is detected to be high, the system switches between mute mode and non-mute mode and outputs the current mute status indication through the mute output pin.

[0084] The mute input pin being active high means that a rising edge on the pin triggers the mute state switch when it transitions from low to high. Switching between mute and non-mute modes means that each active trigger of the mute input pin causes the internal mute state of the noise reduction chip to flip, switching from the current non-mute mode to mute mode, or vice versa. The mute output pin indicates the current mute state; its level is synchronized with the mute status. When the noise reduction chip is in mute mode, the mute output pin outputs a high level; when in non-mute mode, it outputs a low level.

[0085] Specifically, after the input / output control module detects a rising edge transition on the mute input pin, it reads the current internal mute flag state, inverts the flag, and writes it to the register to complete the state flip. If the flag indicates mute mode after the flip, the digital signal processor sets the gain coefficient of the output digital voice signal to zero or attenuates it to an extremely low level to block voice output, while simultaneously driving the mute output pin high. If the flag indicates non-mute mode after the flip, the digital signal processor restores the original gain coefficient to allow normal voice output, while simultaneously driving the mute output pin low. The high-level signal on the mute output pin can be provided to the satellite phone main control processor as a mute status indicator, used to illuminate the mute indicator light or display a mute icon on the screen. Note that in SHI bus mode, the mute input pin is multiplexed as a serial data pin, and the mute switching function is unavailable at this time.

[0086] The method provided in this embodiment achieves real-time response to volume adjustment and mute switching without interrupting the main noise reduction process by monitoring the level states of the volume adjustment pin and the mute control pin in parallel during the noise reduction processing of the noise reduction chip. This improves the concurrent execution efficiency of user operation and noise reduction processing. By monitoring the high-level state of the volume adjustment pin and adjusting the output volume accordingly after the minimum duration, and by performing timed continuous volume adjustment until the pin is released while the high level is continuous, the method effectively distinguishes between single-button presses and long-press operations, avoiding accidental volume triggering and loss of control. By monitoring the high level of the mute input pin to trigger the switching between mute and non-mute modes, and by synchronously outputting a status indication via the mute output pin, the satellite phone master control terminal can accurately obtain the current mute status, improving the reliability and consistency of terminal interaction.

[0087] like Figure 6 As shown, the present invention also provides a noise reduction cavity for satellite phones, applied to any of the above-described noise reduction methods for satellite phones, wherein the structure of the noise reduction cavity is as follows: The noise reduction cavity consists of a sound inlet component 50 and a coupling cavity. The sound inlet component 50 is an independent acoustic component with a sound inlet hole 52 at its open end and seven through holes 54 at its closed end. The coupling cavity is formed by bonding and sealing a front shell 30 and a rear shell 40 of the coupling cavity with adhesive, and a part of the coupling cavity is located outside the rubber sleeve 11.

[0088] A rubber sleeve 11 is fitted onto the outside of the microphone unit 20. The inner wall of the rubber sleeve 11 has a first protrusion 12 and a second protrusion 14 to secure the microphone unit 20. The coupling cavity has five through holes 32 on the side inside the rubber sleeve 11 as sound outlets, and one through hole 42 on the side outside the rubber sleeve 11 as a sound inlet. The outer edge of the through hole 42 of the coupling cavity has an annular convex wall 44, and the sound inlet component 50 is fitted into the inner side of the annular convex wall 44.

[0089] The sound inlet 52 of the sound inlet component 50 is connected to the through hole 42 of the coupling cavity through the through hole 54 at the closed end of the sound inlet component 50, and the through hole 54 at the closed end of the sound inlet component 50 and the sound outlet 32 ​​of the coupling cavity are staggered in spatial position. The coupling cavity is filled with a loose porous sound-absorbing medium 60.

[0090] The original ambient sound enters the cavity of the sound inlet component 50 through the sound inlet hole 52 and is buffered and slowed down. Then, it enters the interior of the coupling cavity through the through hole 54 at the closed end of the sound inlet component 50 and the through hole 42 of the coupling cavity. After being folded multiple times in the coupling cavity and selectively absorbed by the sound-absorbing medium 60, the sound reaches the pickup surface of the microphone unit 20 through the sound outlet hole 32 of the coupling cavity.

[0091] like Figure 7As shown, the present invention also provides a noise reduction device for satellite phones, applied to any of the above-described noise reduction methods for satellite phones, comprising: The acquisition module is used to guide the original ambient sound to the noise reduction cavity for wind noise pre-attenuation to obtain wind noise attenuated sound. An analysis module is used to pick up a first sound signal from the wind noise attenuation sound through a first microphone and a second sound signal from the wind noise attenuation sound through a second microphone. The association module is used to convert the first sound signal and the second sound signal into a first differential signal and a second differential signal respectively through a differential input circuit, and transmit them to the noise reduction chip. The processing module is used to convert the first differential signal and the second differential signal into a first digital audio stream and a second digital audio stream, respectively, through the noise reduction chip; The control module is used to adaptively cancel noise in the first digital audio stream based on the second digital audio stream through the noise reduction chip, thereby generating a noise-reduced digital voice signal.

[0092] This application also provides a computer device, such as... Figure 8 As shown, the computer device includes: at least one processor, a memory, and a computer program stored in the memory and executable on the at least one processor. When the processor executes the computer program, it implements the steps in any of the above method embodiments, or when the processor executes the computer program, it implements the functions of each module / unit in the above device embodiments.

[0093] For example, the computer program may be divided into one or more modules / units, which are stored in the memory and executed by the processor to complete this application. The one or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program in the computer device.

[0094] Those skilled in the art will understand that Figure 8 The computer device described is merely an example and does not constitute a limitation on the computer device. It may include more or fewer components than shown, or combine certain components, or different components. For example, the computer device may also include input / output devices, network access devices, buses, etc.

[0095] The aforementioned processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0096] The memory can be an internal storage unit of the computer device, such as a hard drive or RAM. The memory can also be an external storage device of the computer device, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card. Furthermore, the memory can include both internal and external storage units of the computer device.

[0097] This application also provides a readable storage medium storing a computer program that, when executed by a processor, implements the steps described in the various method embodiments above.

[0098] This application provides a computer program product that, when run on an electronic device, enables the electronic device to perform the steps described in the various method embodiments above.

[0099] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of this application can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include at least: any entity or device capable of carrying computer program code to a photographing device / terminal device, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium. Examples include USB flash drives, portable hard drives, magnetic disks, or optical disks. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electrical carrier signals or telecommunication signals.

[0100] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0101] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0102] In the embodiments provided in this application, it should be understood that the disclosed apparatus / devices and methods can be implemented in other ways. For example, the apparatus / device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0103] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0104] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A noise reduction method for satellite phones, characterized in that, include: The original ambient sound is guided to the noise reduction cavity for wind noise pre-attenuation, resulting in wind noise attenuated sound. A first sound signal is picked up from the wind noise attenuation sound using a first microphone, and a second sound signal is picked up from the wind noise attenuation sound using a second microphone. After setting the loudness level by the bias resistor network in the differential input circuit, the first sound signal and the second sound signal are converted into first differential signal and second differential signal respectively by a single-ended to differential structure, and then transmitted to the noise reduction chip through the differential signal line. The noise reduction chip converts the first differential signal and the second differential signal into a first digital audio stream and a second digital audio stream, respectively. The noise reduction chip performs adaptive noise cancellation on the first digital audio stream based on the second digital audio stream to generate a noise-reduced digital speech signal.

2. The noise reduction method for satellite phones according to claim 1, characterized in that, The process of guiding the original ambient sound to the noise reduction cavity for wind noise pre-attenuation to obtain wind noise attenuated sound includes: The noise reduction cavity includes a sound intake component and a coupling cavity; The original ambient sound is allowed to enter the cavity of the sound inlet component through the sound inlet hole, and is initially buffered and slowed down to obtain a slowed-down sound. The decelerating sound enters the coupling cavity through the through hole of the sound inlet component and the sound inlet hole of the coupling cavity; The wind noise of the deceleration sound is selectively absorbed by the loose porous sound-absorbing medium inside the coupling cavity, thereby obtaining the wind noise attenuated sound.

3. The noise reduction method for satellite phones according to claim 1, characterized in that, The step of picking up a first sound signal from the wind noise attenuation sound using a first microphone and picking up a second sound signal from the wind noise attenuation sound using a second microphone includes: A first sound signal containing speech and residual environmental noise is picked up from the wind noise attenuation sound using the first microphone; The second microphone is used to pick up a second sound signal containing residual environmental noise from the wind noise attenuation sound; Both the first microphone and the second microphone are omnidirectional microphones, and in the call state, the RMS power value of the signal received by the first microphone is 6dB greater than the RMS power value of the signal received by the second microphone, and the frequency response curves of the first microphone and the second microphone are parallel to each other.

4. The noise reduction method for satellite phones according to claim 1, characterized in that, After setting the loudness level through the bias resistor network in the differential input circuit, the first sound signal and the second sound signal are respectively converted into first differential signals and second differential signals via a single-ended to differential structure, and then transmitted to the noise reduction chip via differential signal lines, including: The bias resistor network in the differential input circuit provides DC bias for the first microphone and the second microphone, and the transmit loudness level of the first microphone and the second microphone is configured by adjusting the resistance value of the bias resistor network; The first sound signal and the second sound signal obtained after setting the transmission loudness level are converted into differential form of the first differential signal and the second differential signal through the single-ended to differential structure of the differential input circuit; During the transmission of the first differential signal and the second differential signal to the noise reduction chip via the differential signal line of the differential input circuit, transmission line reflection and ringing are suppressed by the source impedance matching resistor connected in series on the differential signal line, and radio frequency interference is filtered out by the decoupling capacitor connected in parallel to the input of the differential signal line.

5. The noise reduction method for satellite phones according to claim 1, characterized in that, The step of converting the first differential signal and the second differential signal into a first digital audio stream and a second digital audio stream respectively through the noise reduction chip includes: The first differential signal is converted into a first digital audio stream by the first differential analog-to-digital converter built into the noise reduction chip; The second differential signal is converted into a second digital audio stream by the second differential analog-to-digital converter built into the noise reduction chip; The differential analog-to-digital converter has a sampling accuracy of 16 bits, a sampling frequency of 8kHz, and a peak input voltage of 2.4V.

6. The noise reduction method for satellite phones according to claim 1, characterized in that, Also includes: During the noise reduction process performed by the noise reduction chip, the level states of the volume adjustment pin and the mute control pin of the noise reduction chip are monitored in parallel. When the volume adjustment pin is detected to be in a high-level state, the output volume is adjusted accordingly after the minimum duration. If it is detected that the volume adjustment pin remains at a high level after the minimum duration, then four volume adjustment steps are executed continuously within one second until the volume adjustment pin is no longer at a high level. When the mute input pin is detected to be high, the system switches between mute mode and non-mute mode and outputs the current mute status indication through the mute output pin.

7. A noise-reducing cavity for satellite phones, characterized in that, The noise reduction method for satellite phones according to any one of claims 1-6 includes: The sound-inlet component has a sound inlet hole at its open end and multiple through holes at its closed end. The coupling cavity is formed by sealing the front shell and the rear shell. One side of the coupling cavity is provided with a sound inlet hole that communicates with the first through hole, and the other side is provided with multiple sound outlet holes. The sound outlet holes are used to communicate with the pickup surface of the microphone unit. The through holes and the sound outlet holes are arranged alternately in spatial position; The coupling cavity is filled with a loose, porous sound-absorbing medium.

8. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the noise reduction method for satellite phones as described in any one of claims 1 to 6.

9. A readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the noise reduction method for satellite phones as described in any one of claims 1 to 6.

10. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, enables the implementation of the steps of the noise reduction method for satellite phones as described in any one of claims 1 to 6.

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