Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of testing equipment supplier Teradyne (NYSE: TER) are trading 12.8% higher today, nearly meeting their average daily volume in a mere hour of market action.

So what: Teradyne blew the market away with a tremendous fourth-quarter report with 31% year-over-year revenue growth fueling earnings more than double the year-ago period. Looking forward, there's a growing backlog of unfilled orders that should lead to continued business strength in coming quarters.

Now what: Teradyne's particular strength lies in system-on-a-chip (SoC) testing rigs. Many smartphones and tablets are built around SoC solutions, so what's good for ARM Holdings (Nasdaq: ARMH) or MIPS Technologies (Nasdaq: MIPS) is also great for Teradyne. This stock is another proxy for the exploding mobile computing market, in case the household brands make you queasy for any reason.

Interested in more info on Teradyne? Add it to your watchlist.

Fool contributor Anders Bylund holds no position in any of the companies discussed here. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool is investors writing for investors.