TI: Breaking through the constraints of distance, a new audio ADC is born

The rapid development of artificial intelligence technology is causing a huge change in family lifestyles. Smart home products such as smart refrigerators, smart washing machines, smart switches, and sweeping robots are beginning to enter thousands of households. As the core of smart home construction, smart speakers enable people to change from being accustomed to operating with remote controls or buttons to controlling by voice, making human life more convenient and easy. According to market statistics, China has become a huge market for smart speakers. In the first half of 2019, the sales volume of smart speakers was 15.56 million units, a year-on-year increase of 233%, with sales of more than 3 billion yuan, close to the level of the whole year of 2018. With the continuous increase in the volume of smart speakers, the sales scale is expected to exceed 1.2 billion yuan in 2020. At the same time, some institutions predict that in 2020, there will be 50 billion devices in the world that have a demand for audio interfaces. Faced with such a huge market demand, smart speaker technology also faces huge challenges.

At present, a widespread problem with smart speakers is that due to the influence of audio reception distance and environmental noise, the user's voice is often not recognized by the device normally, and it is often necessary to shout loudly into the microphone for it to receive the signal. Recently, Texas Instruments (TI) (hereinafter referred to as "TI") launched a new Burr-Brown ^TM audio analog-to-digital converter (ADC) for smart homes, which can clearly complete voice acquisition at a distance 4 times farther than similar products in the industry. The advent of this audio ADC product has successfully overcome the challenges of far-field audio acquisition faced by smart home systems.

At the product launch conference, TI audio product marketing engineer Mr. Abhi Muppiri and North China technical application manager Mr. Zhao Banduo explained in detail to EEWorld and other media reporters the black technology behind TI's new Burr-Brown ^{TM audio ADC.}

Mr. Abhi introduced that the TLV320ADC5140 is a smaller four-channel audio ADC with the same performance in the industry. It is also one of the three new Burr-Brown ^TM audio ADCs launched by TI. It can achieve low-distortion recording in noisy environments and high-fidelity recording in far fields in any environment. At present, ADC has become a key configuration for audio processing, and together with the continuous upgrading of DAC, it promotes the enhancement and innovation of audio technology. What are the advantages of this newly launched ADC compared with previous products? Mr. Abhi and Mr. Zhao Banduo gave the answers.

     Mr. Abhi Muppiri, Audio Product Marketing Engineer, TI

Smart home systems face the challenge of far-field audio acquisition. Due to the limited number of microphones, the sound source is often far away from them, resulting in poor signal capture by the microphones. In addition, due to the limited ability to reduce noise from inefficient signals, it is difficult for smart home systems to obtain real voice commands in noisy sounds. TI's newly released new Burr-Brown ^TM audio ADC TLV320ADC5140 successfully overcomes the two major challenges of distance and noise faced by audio signal processing.

Mr. Abhi also introduced that TLV320ADC5140 can recognize low-volume sound signals. When the user is far away from the smart device, it is difficult for the smart speaker to hear the user's instructions clearly, and the user often needs to shout loudly into the microphone for many times before it can be recognized. The TLV320ADC5140 allows the microphone to pick up the sound from the sound source more than 10 meters away, with a far-field voice acquisition capability that is 4 times farther than similar products in the industry, and can achieve a signal-to-noise ratio of 120dB, while the size of the ADC chip is only 16 square millimeters.

At the same time, TLV320ADC5140 can also exclude other noisy noises and identify the required voice commands. By utilizing DRE and effective noise reduction, correction and filtering algorithms, the product can accurately sample even in noisy environments.

 Mr. Zhao Banduo, Technical Application Manager of North China, Texas Instruments

In addition to far-field voice capture at 10 meters, the TLV320ADC5140 has many other outstanding features. First, this product can use the beamforming system to enhance the recognition of hard-to-capture voice commands, and can clearly and effectively capture audio in any environment. Second, it has the characteristics of small size and low power consumption, and the built-in functions of this product can greatly reduce the burden of digital signal processing. Third, the TLV320ADC5140 is the first ADC to fully support the latest high signal-to-noise ratio microphones with a dynamic range of more than 106dB, so the microphone provides high-quality voice compatibility. Fourth, the TLV320ADC5140 can support up to four analog channels or eight digital channels (or a combination of them) of microphone input for simultaneous sampling, thus ensuring system flexibility, and also provides programmable functions such as gain and phase calibration to equalize microphone array mismatch. Fifth, the built-in 120dB dynamic range enhancer of this product can enhance low-volume audio signals. Sixth, low-distortion recording can be achieved even when the speaker is adjusted to the maximum volume (greater than 130dB SPL). Other features include programmable gain amplifiers, high-pass filters, channel blending, and linear-phase or ultra-low-latency filters.

Mr. Abni and Mr. Zhao Banduo also gave many examples of the application of the new Burr-Brown ^TM audio ADC. When used in smart homes, this product can be used in many places, such as controlling lamps and air conditioning temperatures, and can also achieve more cross-room audio acquisition and enhance the recognition of hard-to-capture voice commands in applications such as high-end smart speakers, sound bars, wireless speakers, HDTVs, IP network cameras, teleconferencing systems, and smart home appliances.

When applied to cars, Mr. Abni introduced that the application environment of cars is very similar to that of smart homes. There may be more than 20 speakers in the car, and the most important thing is to have a microphone so that you can control and communicate with your voice while driving. The same is true for noise cancellation, which also requires a microphone to collect all kinds of noise, and then use a series of algorithms to cancel the noise.

This product can even be used in security systems. Based on the strong audio directivity, it can be used on some cameras. The digital microphone is turned on because it consumes less power. Once someone breaks in, it can be used to wake up the camera. When waking up, the analog microphone can be turned on to record higher-quality audio sources. If the location is determined at the same time, it can also tell the approximate location, and the camera will move to that location to record and capture the corresponding sound.

At the press conference, Mr. Abni also focused on introducing Burr Brown ^TM audio technology. After acquiring Burr Brown, TI has continued the brand's unique audio technology and development direction, including TI's ADC or DAC, and even Class D noise and audio op amps. TI will also continue the essence and connotation of this brand and strive to provide better products in the audio market.

In recent years, TI has released the Burr-Brown ^TM series of audio technology products, which are mainly aimed at the automotive, professional audio and smart home fields. Its products include analog input 4-channel ClassD car audio amplifiers and digital input 1-channel ClassD car audio amplifiers in the automotive field, as well as audio operational amplifiers in the professional audio field and audio ADCs in the smart home field.

In terms of the market, Mr. Zhao Banduo said that compared with Europe, the United States and Japan, China's smart home is still in a leading position. In addition to smart speakers, set-top boxes, refrigerators, etc. can be used for voice interaction. Currently, TI has cooperated with many leading domestic home appliance manufacturers. I believe that in the near future, people will see more and more products based on TI voice interaction control appearing in the market.