Sundance SMT712 - Manual (Page 8)

User Manual SMT712 Page 8 of 89 Last Edited: 11/12/2012 10:36:00
1 Introduction
The SMT712 is a PXI Express (opt. Hybrid or CompactPCI) Peripheral Module (3U),
which integrates two fast 12-bit DACs, 2 banks of DDR2 memory, a clock circuitry
and a Virtex5 Xilinx FPGA, under the 3U format.
The PXIe specification integrates PCI Express signalling into the PXI standard for
more backplane bandwidth. It also enhances PXI timing and synchronisation
features by incorporating a 100MHz differential reference clock and triggers. The
SMT712 can also integrate the standard 32-bit PXI (Hybrid) signalling as an option or
a standard 32-bit CompactPCI.
Both DAC chips are identical and can update their output at up 2.3 Giga-samples per
second each, with a 12-bit resolution. The manufacturer is Maxim and the part
number is MAX19692. Digital-to-Analog converters are clocked by circuitry based on
a PLL coupled with a VCO in order to generate a low-jitter fixed signal. The
MAX19692 is capable to achieve SFDR figures close to 70dBs. Each DAC integrates
settings depending on the type of frequency response required.
The on-board PLL+VCO chip ensure a stable fixed sampling frequency (maximum
rate), in order for the board to be used as frequency synthesizer without the need of
external clock signal. The PLL will be able to lock the VCO either on the 100MHz PXI
express reference (or 10MHz PXI reference depending on option) or on an external
reference signal. The sampling clock for the converters can either be coming from
the PLL+VCO chip or from an external source. The reference clock selected is also
output on a connector in order to pass it to an other module.
The Virtex5 FPGA is responsible for controlling all interfaces, including CPCI (32-bit
33MHz), PXI (32-bit) and PXIe (8 lanes allocated – depending on PXIe chassis, 4 or 8
lanes would be used), as well as routing samples. The SMT712 is populated with an
XC5VLX110T-3.
Two DDR2 memory banks are accessible by the FPGA in order to access data on the
fly. Both banks are individually clocked at 312 MHz.
One or two SHB connector(s) is(are) available in order to collect data/samples from
an other Sundance module (depending on the option). The first SHB connector is
available on all versions of the board, whereas the second SHB connector is only
available on the non-PCI versions.
All analog connectors on the front panel are SMA.
Examples of application where the SMT712 can be involved in are wideband
communication, radar, wireless modem, software radio or waveform generator
systems.