Audio codec integrates single microphone noise/echo cancellation
The TC94B24WBG is claimed to offer design flexibility, performance, and cost benefits so OEMs can better address challenges associated with multiple microphone audio processing. Besides processing the NC/EC algorithms, the high-performance, low-power general-purpose programmable DSP in the TC94B24WBG allows customers to implement their own software in the audio codec. This helps differentiate their products from the competition. Additionally, the highly integrated TC94B24WBG includes: a 2-channel AECM interface; a 4-channel DECM interface; a battery-conserving class-G headphone amplifier; ear speaker amplifier; asynchronous sampling rate converter; a 4-channel I2S interface; an I2C/SPI interface; and audio post processing (equalizer, dynamic range controller). It provides all of the audio inputs and outputs required by mobile and telephony products.
The device interfaces with the audio I/O and the application processor in smartphones and tablets. The TC94B24WBG comes equipped with two analogue and four digital microphone inputs to suit various customers’ needs. However, Toshiba’s unique audio processing algorithm needs just one analogue microphone to efficiently provide NC and EC simultaneously. Outstanding noise cancellation on the TC94B24WBG is achieved through a Toshiba proprietary one microphone algorithm. The algorithm distinguishes voice and noise with statistical noise estimation while Toshiba’s improved minimum mean square error method in frequency-domain removes noise only and keeps the voice natural. The excellent echo cancellation algorithm has a time-domain echo cancelling adaptive filter and frequency-domain echo suppression. The former removes linear echo, the later suppresses the rest of non-linear echo. These two main processes work together closely and intelligently to achieve high quality echo cancellation by the same microphone used for the noise cancellation.
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