How to deal with the analog-to-digital converter under the voice "call"?

Voice has become the focus of competition for smart homes.

In addition to smart speakers, educational robots, etc. have already tested the water first, more products such as air conditioners and refrigerators are also waiting for the voice "call" in the new wave of smart home. With the increase in complexity, it is also about accuracy. Higher requirements. How does a voice system solution work?

Different challenges

If you count the difficulties of voice control in smart home systems, what you need to face most is undoubtedly the challenge of dealing with distance and noise.

Abhi Muppiri, audio product market engineer at Texas Instruments, said: "In actual application scenarios, the volume of the acquisition is too low due to the long distance or large space, which often affects the effect of voice control. In addition, in noisy environments, It is also a challenge to accurately identify sound signals. "

Moreover, due to the "location" of smart appliances and different configuration requirements for microphones, the voice solution needs to be adjusted flexibly and effectively.

"For example, the air conditioner is generally hung on the wall, and the distance will be a big problem. And if it is placed in the living room, there will be additional noise such as TV sound and it needs to be identified and eliminated. Therefore, different applications have different needs and need Customer terminal considerations are adjusted accordingly. "Abhi Muppiri analyzes.

ADC mission

In response to the above requirements, in addition to the continuous improvement of the processing rate of voice chips, the ADC (Analog-to-Digital Conversion) that implements the processing of sampling, compression, and EQ of voice signals must also be continuously "optimized."

"The demand for ADCs in the audio market is reflected in high signal-to-noise ratio, high sampling rate, etc." Abhi Muppiri mentioned.

As an indispensable microphone in a voice solution, the "cooperation" of the ADC is also required. Abhi Muppiri further pointed out that commonly used digital or analog microphones in the market, when pre-researching related products for customers, different ADCs are required to cooperate with the test in order to help choose a more cost-effective solution.

"In general, digital microphones consume less power than analog microphones, but analog microphones have better signal-to-noise ratios than digital microphones," Abhi Muppiri said when analyzing the pros and cons of the two.

Based on this challenge, TI's new generation Burr-Brown audio ADC--TLV320ADC5140 came into being.

ADC optimization

As the industry's smaller four-channel audio ADC with equivalent performance, the TLV320ADC5140 has extraordinary capabilities. It can achieve low-distortion recording in noisy environments, and can also perform far-field high-fidelity recording in any environment. It can capture clear speech more than 10 meters away from similar products in the industry, that is, the sound source exceeds 10 meters.

Abhi Muppiri, as many families say, realizes many advantages. One is the use of a beamforming system. The built-in 120dB dynamic range enhancer (DRE) enhances low-volume audio signals while maintaining low-distortion recording. Far-field high-fidelity recording in any environment. The second is the ADC that supports the latest high signal-to-noise ratio microphones with a dynamic range of more than 106dB, providing high-quality voice compatibility. The third is integrated support for multi-functional system design. It supports simultaneous sampling of up to four analog channels or eight digital channels (or a combination thereof) of the microphone input to ensure system flexibility. It also provides programmable functions such as gain and phase calibration to equalize microphone array mismatches. .

With so many "protection methods", TLV320ADC5140 achieves high cost performance. Not only the power consumption of each channel of this product is only 9.5mW at 48kHz, but also it can reduce the design volume without sacrificing system reliability.

All of this is inseparable from TI's "reengineering" of Burr-Brown. You know, Burr-Brown is a veteran of quality audio. After being acquired by TI, TI continues the essence and connotation of Burr-Brown, and continues to develop audio products for automotive, professional audio and smart home related products. TLV320ADC5140 has become a big “endorsement”.

Abhi Muppiri finally mentioned: "TI has launched a series of audio solutions including ADC, DAC, Class-D, forming a complete closed loop."