Semiconductor giant Intel Corp. and Analog Devices Inc. are expected to announce today a joint development venture that is expected to mark Intel's entry into the booming digital signal processor arena. The two companies are expected to announce plans to develop embedded chips for hand-held computing devices, according to industry sources. A spokesman for Santa Clara-based Intel declined to provide any details, except to confirm that the two companies will hold a news conference and a teleconference this afternoon. Analog Devices, based in Norwood, Mass., is a developer of analog chips and digital signal processors, one of the fastest-growing areas of the semiconductor industry. Digital signal processors are used in cellular phones, pagers, digital cameras, modems and video equipment.