High-dynamic-range audio processor spans extended audio range

June 26, 2014 // By Graham Prophet
STMicroelectronics has introduced the first audio processor to incorporate HDR (High Dynamic Range) audio-signal acquisition technology. This highly integrated device combines all the leading-edge audio-processing technologies into a single solution.

The high level of integration offered by the STA311B processor makes it suitable for a wide range of home systems, from entry-level to high-end equipment. HDR signal acquisition allows digital signals with a dynamic range exceeding 130 dB to be generated without the need for expensive, high-performance ADCs (analogue-to-digital converters). This technique, for which ST has a patent application pending, allows the STA311B to process sounds as low as a whisper or as high as jet engine noise with the same degree of clarity, delivering an unprecedented audio quality.

In a 8.0 x 8.0 x 0.9 mm VFQFPN package, the STA311B embeds eight audio-processing channels with up to 10 independent user-selectable biquadratic filters per channel, input and output mixing capabilities, multi-band dynamic range compression, advanced pop-free operation, auto-detection of input sampling frequency, input and output (pre- and post-processing) RMS (Root Mean Square) metering, ST's proprietary FFX Pulse Width Modulation technology, and HDR acquisition inputs, in a single device. This allows audio equipment and subsystem manufacturers to reduce costs by developing multiple products based on the same design still tailored for a variety of price/performance scenarios.

The STA311B’s input/output RMS metering function delivers an increased level of safety to the final product without any additional hardware cost. Whereas previous solutions relied on using over-specified and more expensive speakers capable of sustaining high power peaks, the STA311B allows the application to suppress unwanted energy surges that could potentially damage the speakers. The STA311B’s pop-free circuitry also enables a seamless start-up, eliminating unwanted noise due to the bridge charge sequence in both single-end and bridge-tied load configurations.

The latest member of the Sound Terminal product family, the STA311B is supported by ST’s free APWorkbench software development tool that allows all ST audio products to be configured via a graphical interface ( www.st.com/apworkbench).

STA311B costs $3.00 (1000).

STMicroelectronics; www.st.com

“ST has been a leader in semiconductor audio since practically the beginning of audio