Spring 2009 Vol. 18, No. 1

Features Two or four 125 MHz, 14-bit A/Ds; two or four 500 MHz, 16-bit D/As Four or eight DDCs (downconverters) and one or two DUCs (upconverters) Up to 1 GB of DDR SDRAM One or two Xilinx Virtex-II FPGAs Input signal bandwidths to 50 MHz Sample clock synchronization to an external system reference LVDS clock/sync bus for multiboard synchronization Up to 2.56 seconds of delay or data capture at 100 MHz Optional factory-installed IP cores available

General Information

Model 7741 is a software radio transceiver suitable for connection to HF or IF ports of a communications system. It is available with either two A/D and two D/A converters (Model 7741) or four A/D and four D/A converters (Model 7741D), and is capable of bandwidths to 50 MHz and above. It attaches directly to motherboards with full length PCIe (PCI Express) interface slots for installation in various PCs, blade servers and computer systems.

A/D Converter Stage

The front end accepts two or four fullscale analog HF or IF inputs on front panel MMCX connectors at +10 dBm into 50 ohms with transformer coupling into the LTC2255 14-bit 125 MHz A/Ds. The digital outputs are delivered into the Virtex-II Pro FPGA for signal processing or for routing to other module resources.

Digital Downconverter

The 7741 features one or two TI/Graychip GC4016 quad DDCs, each accepting either four 14-bit or three 16-bit digital inputs from the FPGA which determines the source of GC4016 input data. These sources include the A/Ds, FPGA signal processing engines, SDRAM delay memory and data sources on the PCI bus.

Digital Upconverter

A TI DAC5686 digital upconverter and dual D/A is attached to each FPGA, accepting baseband real or complex data streams with signal bandwidths up to 40 MHz. When operating as an upconverter, it interpolates and translates real or complex baseband input signals to any IF center frequency between DC and 160 MHz. It delivers real or quadrature (I+Q) analog outputs through two 320 MHz 16-bit D/A converters to two front panel MMCX connectors at +4 dBm into 50 ohms.

Virtex-II Pro FPGAs

One or two Xilinx XC2VP50 Virtex-II Pro FPGAs serve as control and status engines with data and programming interfaces to each of the on-board resources including the A/D converters, DDCs, DUCs, and D/As.

PCIe Interface

The 7741 includes a multiple port, 48-lane Gen 2 PCIe switch with integrated SerDes. The switch provides 16X wide connection to the PCIe interface, allowing high-speed data transfers to and from the motherboard. Switch ports each include buffer memory to minimize bottlenecks, with two 4X PCIe connections provided to each FPGA, as well as one 4X connection to each 64-bit PCI interface.

For more information and price quotation on the Model 7741, click here or on the Model 7741D, click here.