This hardware was built to measure the noise spectrum of a warm E2V CCD231 4Mpix CCD. It consisted of a simplified CCD controller onto which the CCD could be directly plugged.
The heart of the controller was an Opal Kelly Spartan3-based FPGA module. This performed as a clock sequencer , ADC buffer and USB interface to the host PC. These Opal Kelly modules are excellent products. They allow high speed data streaming across the USB interface and come with their own royalty-free drivers and the “FrontPanel” SDK that can be incorporated into the user’s application code. The Opal Kelly boards also contain large amounts of SDRAM that can be used to buffer data if the acquisition speed exceeds that of the USB interface.
The CCD231 video output waveform could only be sampled for a few ms at a time due to the need to flush accumulated dark current from the serial register and also in order to restore the AC coupling in the CCD’s output MOSFET amplifier. By leaving the system running for several minutes it was possible to accumulate thousands of noise waveforms. Each was then independently FFT’ed and the resultant spectra averaged. Some examples are shown below.
