By contrast, Fig. 2 shows how the NGC will be connected to a head for AO. In Fig. 2, the same Linux PC is used, but the functionality of the frontend electronics shown in Fig. 1 has been reduced to a volume of only 100^200x40 mm. The complete NGC front-end electronics needed to drive the L3Vision CCDs will be repackaged in two Eurocard size PCBs (160x100 mm) connected via high-speed serial links at 3.125 Gbps. The connection of the AO head to the back-end electronics is done through optical fiber and via the Front Panel Data Port (FPDP) protocol .
In the configuration of Fig. 2 the AO head sends the pixel data directly to the real-time computer for number crunching. However, another possible alternative to connect the AO head to the RTC is shown in Fig. 3. In this figure the back-end computer receives the pixel data from the front-end head and transmits it to the RTC for processing. The RTC is a multi-processor VME-based board with a commercial FPGA03 piggy-back daughter card for pre-processing, image calibration and centroiding .
Was this article helpful?