Pentek VIM-2 module improves wireless signal quality

The Model 6236 ADC Velocity Interface Mezzanine (VIM)-2 module from Pentek Inc. enables multi-carrier software radio architectures in wireless basestations to achieve higher levels of signal quality, as well as to keep pace with future wideband air interface standards.

Based on Analog Devices Inc. AD6645-105 14-bit monolithic ADC, the two-channel VIM-2 board operates at sampling rates up to 105MHz and delivers two additional bits of resolution over its 12-bit predecessor for improved SNR performance.

The Model 6236 also features a configurable XC2V1000 or XC2V3000 FPGA from Xilinx Inc.'s Virtex-II family. Both ADC outputs are connected directly to the FPGA to facilitate compute-intensive signal processing functions within the module. The FPGA can deliver either wideband ADC data or processed results directly to the processor board through dual 400MBps mezzanine interfaces.

The FPGA can be installed with a GateFlow core that includes functions such as FFT and digital receivers. Utilizing proprietary block memory architecture, the GateFlow FFT executes a pipelined complex 4k-point radix-4 FFT in <10?s. On the Model 6236, real-time FFTs are computed for both channels with 50 percent input overlap processing and zero data loss. A 1k-point version of the FFT is also available.

The Model 6236 also offers two different wideband digital downconverter options, both with decimation ranges from 2 to 64. The user can choose two Graychip GC1012B digital receiver ASICs or add Pentek's GateFlow wideband digital receiver core.

The VIM-2 board attaches directly to all of the company's quad C6000 DSP and PowerPC boards and can be easily combined with various PMC and VIM I/O products, including high-speed ADCs, FPDP, RACEway, and digital upconverters, all within a single VMEbus slot.