AT&T has invested in PicoChip, a Bath, England-based maker of WiMAX and HSDPA digital signal processors. The amount of the investment was not disclosed.

AT&T Corp., a subsidiary of AT&T Inc., made the investment, according to PicoChip, which was founded in 2000 and has raised $44 million in three rounds of investor funding since then. The third round, completed in June of 2005, raised $20.5 million. Previous investors include Scottish Equity Partners, Rothschild, Intel Capital, Pond Venture Partners and Atlas Venture.

PicoChip, a member of the WiMAX Forum, makes high-performance DSPs for wireless gear, and has developed reference models for both WiMAX and HSDPA networks, including Mobile WiMAX.

“During our third round of funding we set aside a certain number of shares in anticipation of a relevant strategic investor coming along,” said Guillaume d'Eyssautier, president and CEO of picoChip, in a prepared statement. “It is a major testimony to our growing stature in the wireless industry that an industry figurehead such as AT&T wishes to invest in picoChip.”