Harris Semiconductor announced the availability of a new software-driven programmable digital downconverter (PDC) optimized for use in cellular basestations that delivers multiple channel processing of high dynamic range transmission protocols. The CommLink HSP50216 PDC contains four channels that can support up to four different cellular protocols simultaneously, including CDMA, TDMA, IS-95, GSM, 3G (such as wide-band CDMA), and legacy protocols such as AMPS.

The HSP50216 provides cellular operators with the flexibility to move between any existing air interface standard, employ a higher number of channels and offer frequency plans with greater efficiency. This new software radio receiver chip also provides a resampler function, which allows the user to adapt the output data rate to meet protocol specific needs on a per channel basis. This function is further enhanced by the addition of sync outputs that accompany each of the HSP50216ıs four channels. Competing products on the market contain only one output synchronizer; Harrisı design employs one for each of its four channels.

"The announcement of our new digital downconverter solidifies Harrisı position as the industry leader in digital radio design for basestations," said Geoff Phillips, vice president of Signal Processing & Telecom Products at Harris. "We are the first company to bring to the market a programmable digital downconverter chip that integrates everything but the baseband processing on a single IC, and our next generation PDC delivers these capabilities along with superior multichannel functionality that can simultaneously address multiple standards. Most importantly, Harris can deliver on the unique system-level needs of our customers, as a result of our shared expertise from Harris Corporation, long recognized as a major player in system level digital radio."

Designed to interface between a high-speed analog-to-digital converter (ADC) and the baseband processor, the HSP50216 can handle up to an 80 megasamples-per-second (MSPS) input. The device not only gives designers the digital dynamic range potential of software-controlled radio, but it also solves DSP processor bandwidth limitations, cuts software and hardware overhead and eliminates stand-alone ICs, such as Cartesian-to-Polar converters. The result is smaller, lower-cost equipment with more functionality. The HSP50216 operates at three volts, a significant improvement over its existing PDC, the 5-volt HSP50214. As a result, the

HSP50216 reduces per-channel power consumption by 75 percent. Board space reduction is accomplished by the use of a small outline Ball Grid Array (BGA) package, which results in a smaller footprint than the existing MQFP package used on the HSP50214.

There are a number of important firsts here: This is the first DPC to offer four channels, the move to 3 V opens the doors for portable uses down the road, and the input bandwidth is high enough to allow for most expected applications. The out-of-band attenuation is superb and reduces the limitations of the full software radio. The accepted input of 80 Msample/s represents an RF bandwidth of about 200 MHz into the ADC that would lead the part.

Harris is well ahead in this variable architecture radio. The company also has under development the matching digital upconverter, for which a 14-bit DAC is already available. The necessary 14-bit ADC for this downconverter is also expected to be available later this year.