As a leader in sensory experience solutions, AAC has devoted greater research and development efforts to the automotive field in recent years to improve its automotive product matrix and accelerate its automotive business.
Its automotive business ushered in new progress a few days ago when it successfully developed a complete set of new automotive MEMS microphone module products, including voice microphone modules, emergency call (eCall) microphone modules, waterproof microphone modules, and ACC modules to fully meet the functional needs for multi-zone voice call/control, voice control, active noise cancellation (ANC), siren detection, and more.
From the design and packaging of sensor chips to the design and assembly of the structure, the whole process of this new product series has been localized. Compared with single MEMS microphones, modular products can dramatically boost value and effectively enhance the overall business development. Having reached cooperation with world-renowned automobile manufacturers, AAC Technologies will mass produce such module products this year.
MEMS Microphones Are Replacing ECM Microphones to Meet Diverse Automotive Sound Pickup Needs
As miniature microphones made by etching membranes on silicon wafers through MEMS technologies, MEMS microphones, compared with traditional ECM microphones, feature obvious advantages in acoustic performance, reliability, power consumption, and other areas. They have widely replaced traditional ECM microphones to serve as core basic components for human-computer voice interactions and sound environment perceptions in intelligent vehicles.
Such microphones boast digital pulse-density modulation (PDM) and analogue output modes, small size, ultra-high consistency, low total harmonic distortion (THD), flat frequency response, and other excellent characteristics. With a SNR ratio of 63 dB to 70 dB, they can meet the application needs of different levels and scenarios. They also meet the relevant quality requirements of AEC-Q103-003, a standard for automobiles, and can work under a temperature range of -40°C to 105°C.
The AAC Intelligent Cockpit Voice System Is Provided to Support More Complex and Diverse Application Scenarios
In addition to high-performance single microphones, AAC Technologies can also provide platform-based or customized modular voice products, covering most application scenarios of automotive voice, enabling a better voice experience for drivers and passengers.
Voice Microphone Modules
Microphones are rarely seen on traditional vehicles. Sometimes one or two microphones are arranged around the driver’s seat to enable voice interaction and commands. However, the pickup effect by a single omnidirectional microphone at the target sound source is less than satisfactory as it cannot achieve effective noise reduction of the surrounding ambient sound. Also, automotive voice assistants needs to accurately distinguish voice commands issued by the driver and the occupants of different seats to avoid wrong responses.
AAC Technologies can provide voice microphone modules with customizable parameters such as form factors and structures, number of microphones, acoustic indicators, interfaces and more. A multi-position microphone array allows voice recognition, wake-up, and voice interaction at multiple positions in the vehicle and effectively solves the problem of sound pickup in the main direction. Combined with algorithms, it can dramatically eliminate ambient noise and enable more intelligent and precise active vehicle-to-human interactions.
E-Call Microphone Modules
E-Call, a life-saving feature for intelligent transportation, has been realized after the connection of vehicles to the 2G cellular network. If a serious traffic accident occurs, the system will establish a voice connection with the nearest rescue center through a mobile phone and emergency rescue feature, and report the location as well as other information about the vehicle.
In China, the coverage of such a system is increasing in recent years. Boasting a high sensitivity and SNR, the eCall microphone modules developed by AAC Technologies can enable the people to instantly request assistance from service centers even when they are at a position that is inconvenient or difficult for them to talk or communicate.
Waterproof Microphone Modules
With the popularization of intelligent voice control in vehicles, voice control outside vehicles is becoming more and more important. For example, the vehicle’s owner can use voice control when close to the vehicle to open the trunk or turn on the air conditioner, start the vehicle in advance or perform other actions. Ambient and other unwanted sounds outside vehicles can be ignored easily with the advancement of sound insulation technologies.
With a protection rank of IP6K9K, the automotive waterproof microphone modules of AAC Technologies can effectively prevent the intrusion of dust and high-temperature and high-pressure water, and will not be damaged even in severe weather and environments. Arranged on the exterior of the vehicle to receive ambient sounds, they can reduce the music volume and sound prompt tones to alert the driver to effectively avoid safety accidents when the sensor captures sirens or other sounds that the driver should know about.
ACC Modules
Main noises produced by traditional vehicles include mechanical noises of the power system, fluid noises, and noises caused by the friction between the tires and the road surface. With the maturity of the EOC system, the popularization of electric and hybrid vehicles, and improvement of the acoustic insulation coefficient of vehicle bodies, road noises have become an important factor affecting the driving experience. Because of this, road-noise active noise control (RANC) technology is becoming more popular in intelligent vehicles, eliminating the impact of road noises while driving.
The RANC system requires the cooperation of ACC, microphones, and speakers. The full-scale acceleration of the ACC module produced by AAC Technologies reaches up to 16 g, which is sufficient enough to cover the usual vibration amplitude range. With a maximum bandwidth of 4 kHz, it can accurately monitor the vibrations of tires and the suspension. To ensure driving comfort, speakers in the vehicle will send out inverted acoustic signals to reduce road noises actively, after which the residual noises captured by microphones in the vehicle are processed by algorithms.
At present, AAC Technologies is in the top three in the world in terms of MEMS microphone shipments, and it has reached long-term and stable cooperation with global leading automobile manufacturers. Together with automotive speakers, linear actuators, optical lenses and modules, and other software and hardware integration products of the Group, the complete set of new automotive modules will form a full sensory experience product matrix for intelligent vehicles, facilitate further in-depth cooperation with automobile manufacturers, and accelerate the rapid development of the automotive business of AAC Technologies.