Portfolio of work : 16 channel Acoustic Signal Generator and Receiver for submarine sonar program.
Members of the BBSP team developed these two PCI Express cards as part of a technical refresh of a US Navy submarine sonar system. The cards were developed as modules that could be connected together to vary the channel count of the system for different applications. While the AD7760 provided a very high performance oversampling ADC for the receive module, no DAC counterpart capable of similar performance existed for the transmit module. Our solution was to instantiate a 16 channel interpolation engine in a Xilinx Virtex 5 FPGA. The outputs of the interpolation engine fed 16 high speed DACs running at the oversampling clock rate of the ADC. This allowed the transmit card to perform as a mirror image of the receive card without increasing the processing load on the host system, or the data rates on the PCIe links. The interpolation feature also greatly simplified the reconstruction filter requirements at the transmit section outputs.