Baseband Processor Uses 802.11 CCK Modulation

The HFA3860B baseband processor is being called the world's first device of its type to adopt the complementary code keying (CCK) modulation technology proposed in the IEEE 802.11 high-speed WLAN global standard. The chip, which drops into the company's Prism radio chipset, has been developed in anticipation that approval of the standard for high-speed wireless networking, which is expected to occur in mid-1999, will open the door for interoperable WLAN products that are compatible with wired Ethernet.The IC comprises the baseband processing engine of the physical layer and contains all the functions necessary for a full- or half-duplex packet baseband transceiver. It can replace the HFA3824A and HFA3860A chips in the company's Prism radio reference design. The chip builds upon the earlier HFA3860A baseband processor, which used M-ary Bi-Orthogonal Keying (MBOK) modulation technology to achieve 11-Mpbs data rates.On-board the new IC are A/D converters for analog I and Q inputs, matched for the HFA3724/6 IF QMODEM chip. Differential phase-shift keying modulation schemes with data scrambling capability are available, as are CCK and MBOK to provide a variety of data rates (11, 5.5, 2 and 1 Mbps). As a result, the chip is backward-compatible with 1- and 2-Mbps, 802.11-compliant DSSS systems that are now on the market.The chip's low-profile TQFP housing makes possible very compact WLAN products such as PCMCIA Type II cards. Its low operating voltage of 2.V to 3.7V delivers long battery life in portables.