multi channel optical interrogator with analogue outputs
Utilising powerful floating-point Sharc DSPs from Analog Devices and an Altera Cyclone FPGA, this optical interrogator delivers both multi channel and multi parameter processing of optical signals.
Dedicated proprietary processing algorithms provided to us had to be heavily modified to significantly improve the throughput speed including the use of the Sharc on-chip dedicated hardware FFT units to ensure the system could track the optical sensor being interrogated up to 50kHz.
The multiple processing algorithms within the DSP yield a number of processed outputs which are presented to the user via a set of analogue voltage outputs through the front panel BNC connectors. Configuration provided by the host / micro-controller allow the user to select which parameter they wish to measure from each BNC output.
Scheduled triggering and clocking is carried out the FPGA, ensuring that the system remains synchronous and locked between channels.
Providing system housekeeping is an NXP ARM 7 micro-controller. Via a dedicated USB connection to a host computer, the micro-controller handles all on-board storage of calibration data and firmware for both the DSPs and FPGA along with performing scheduled monitoring tasks and event logging to SD card storage. Running the SLD, temperature controllers and analogue calibration outside of the DSP domain is also performed by the micro-controller.
Calibration data is read from a USB port provided for each channel such that simply inserting a memory stick with calibration data on will trigger a check for the presence of new calibration data which will be copied to non-volatile storage and the relevant DSP. New firmware may be loaded in the same way.
The entire card operates from a single +12V supply consuming under 25 watts of power.