Wednesday, May 14, 2014

Using a smaller BOM to make less boom

Don't know about you, but where I live, the price of gas has rocketed through the troposphere and is fast approaching the upper stratosphere. Which is to say, it has gone through the proverbial roof. It was almost $1.40 a liter (over $5 a gallon) the last time I stopped at a pump and is set to climb even higher, now that summer is approaching.

Small wonder that, for many car buyers, fuel economy is top of mind. Automakers are wise to this and have adopted a variety of measures to make their cars sip gas more slowly. For instance, many cars now deactivate cylinders when engine load is light and use fewer sound-damping materials to shed weight — because schlepping fewer pounds means less work, and less work means less gas.

These techniques save gas all right, but at a price: increased engine “boom” noise that can both annoy and fatigue the driver — not to mention everyone else in the vehicle. That's a problem. To address it, automakers use active noise control, or ANC, which plays noise-cancelling signals over speakers in the vehicle cabin. All fine and good, but until now, ANC solutions have used dedicated hardware, which can drive up Bill of Materials (BOM) costs and make it difficult to leverage the latest ANC technologies.

What to do? That's the subject of a recent whitepaper by my inestimable colleague Tina Jeffrey. Tina outlines some design considerations for ANC systems (choosing the right microphones makes a difference, for example) but mostly, she focuses on the advantages of running ANC logic on the processor or DSP of the car's infotainment system — as opposed to on a dedicated ANC module.

The benefits are many, including lower BOM costs, greater design flexibility, better cooperation between various acoustic functions in the car and — here's the one I like — less boom. But why sit there listening to me drone on about this? Download Tina's paper now and get the real deal.

Software-based ANC: a smaller BOM, with less boom.

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