ANC active anti-noise bluetooth headset based on Qualcomm QCC3003+AMS AS3418
With the popularity of bluetooth headset, the price of bluetooth headset is increasingly competitive.In addition to the user's requirement for high-pitched quality when listening to music, the user also hopes that the bluetooth headset can have special functions. In response, the anti-noise function of the bluetooth headset comes.
On the road, on the MRT, in the coffee shop or even in the office, we can see more and more people wearing wired earphones or bluetooth earphones. These people may be enjoying the baptism of high quality music, or simply enjoying the quiet feeling brought by noise-cancelling earphones.Below let us discuss what kind of noise headphones can bring us the convenience of life.
Headphones (down) the noise resistance there are two ways, the first is called passive noise, the material of the use of headphones and the sound cavity structure to achieve noise requirements, but can't handle this kind of passive noise low frequency noise, such as automobile, aircraft engine noise, fan rotation of motor noise, or the MRT train running noise in orbit.Another disadvantage is that the passive noise-cancelling method will completely isolate the external sound when wearing the headphones. Of course, it also includes the voice of friends calling you or the sound of the car approaching the engine when walking on the road, which also brings the risk of wearing the passive noise-cancelling headphones.
The second is Active Noise Cancelling ANC. The principle of Active Noise Cancelling is to use the special anti-noise microphone in the headset to pick up the environmental Noise source, and then generate a reverse sound signal through the DSP calculation and processing built in the chip to offset with the environmental Noise to achieve the function of Active anti-noise.The advantage of active noise rejection is that it can deal with low frequency noise very well.In addition, the DSP fine tune can also generate a usage scenario called talk-through mode, which means you don't need to take off the integrated earphone to hear the outside sound, completely overcoming the disadvantages of passive anti-noise.In DSP, active anti-noise processing can be divided into analog processing and digital processing. Analog processing is used in this scheme.Therefore, the required RLC series will be more complex and the layout space will be larger. The following figure shows the ANC filter adapted by this scheme with this headset, and its performance is better than that of AS3418.The only drawback is that the ANC filter is only applicable to this headset and cannot be directly copied to other headphones.
QCC3003 is a support BT5.0 entry level of the flash chipset type stereo bluetooth headset, QFN package to simplify layout, coupled with detailed FAE are almost all of our team has more than 10 years experience in customer support, so in this scheme takes advantage of the work on the accumulation of rich experience to do bluetooth hardware design, the most of the hardware resources on common design the ANC filter with AMS.As the standard code of ADK can almost meet 90% of the requirements of this scheme, the software resources are only used to control on and off AS3418 ANC through I2C of QCC3003.It greatly reduces the cost of software and hardware engineering staff resources.Only the acoustic engineer of the client is required to perform the one MIC cVc of fine tune QCC3003, because this is the different acoustic structure of each earphone, and the fine tune for different MIC positions is required to achieve the optimized echo cancel and noise reduction performance of this earphone.
Combined with the above active anti-noise advantages, the convenience of bluetooth wireless communication allows you to completely get rid of the "entanglement" of cable, and the fine tune optimization of cVc allows you to enjoy high-quality calls, making this program a practical, low-cost and differentiated bluetooth headset.
Scheme block diagram
Core technology advantages
1. The Dual mode BT5.0
2. Excellent RF performance: 9dBm(typ) transmit power and -92.0 dBm(typ) product /4 DQPSK receiver sensitivity
3. Support OTA to update firmware
4. Support Wideband speech
5. Support bluetooth HID remote camera control
1. Support 1 mic cVc noise reduction and echo cancellation
2. Support feed-forward active noise suppression
3. Support AAC audio codecs
4. Support settable EQ
Qualcomm QCC3003 AMS AS3418 ANC active anti-noise bluetooth headset 3003 3418