The electronics includes a 10.000V precision voltage source which is used to provide on-board calibration of the housekeeping data. The output of the precision source is stepped down through a precision resistor chain to provide voltages of 10.000, 7.500, 5.000, 2.500, and 0.000 V. Since CUBIC uses a single ADC for both housekeeping data and science data, this precision source also calibrates the digital conversion of the science data. The gain of the analog signal chain is monitored by measuring the output channel of the onboard X-ray calibration sources. This provides an end-to-end calibration check for the science data system.
The Crystal CS5012A ADC is self-calibrating. It will be calibrated by the ICP boot code and will be re-calibrated every time a Data Collection Mode ON serial command is sent. This will ensure that the ADC is calibrated when data collection is active, and will also provide a means of forcing a calibration ``manually'' by sending serial command SC18.