Freescale Semiconductor's ( FSL) second-quarter profit more than doubled, surpassing Wall Street's expectation, as gross margin improvement boosted the bottom line.The chipmaker's earnings rose to $260 million, or 61 cents a share, from $122 million, or 29 cents a share, a year earlier. The latest quarter's earnings included one-time tax gains totaling $14 million, or 3 cents a share. But even without the gains, the results still easily topped analysts' mean estimate of 49 cents a share, according to Thomson First Call. Revenue rose 9% to $1.6 billion from $1.47 billion, beating analysts' target of $1.55 billion. Gross margin improved to 46% from 41% a year earlier, which Freescale attributed to higher sales and improvements in its product mix. For the third quarter, the company forecast revenue of $1.525 billion to $1.625 billion, with gross margins in line with the second quarter. Analysts, on average, predict third-quarter revenue of $1.56 billion. Freescale was spun off two years ago from Motorola ( MOT), which remains one of its biggest customers. Motorola on Wednesday posted solid second-quarter numbers that blew by estimates. Freescale's second-quarter sales to wireless and mobile customers, such as Motorola, climbed 23% to $514 million. Sales within its largest segment, transportation and standard products, rose 7% to $697 million, while networking sales dropped 4.4% to $370 million. The company's shares recently were up 82 cents, or 2.8%, to $29.80 in after-hours trading.