In order to achieve the performance required for the physics analysis, the readout electronics has to perform the following functions:
1. Amplify the incoming signal.
2. Shape the amplified signal and remove the tail arising from the ion drift.
3. Apply two thresholds, one for tracking functionality (low threshold to detect minimum ionizing particles) and one
for transition-radiation functionality (high threshold to detect transition-radiation X-rays).
4. Obtain timing information for the low-threshold signal in order to yield the proper position resolution (and hence momentum resolution).
5. Store the timing information in a pipeline and whether or not the input signal exceeded the low- and high-threshold
values every bunch crossing during the full level-1 trigger latency.
6. For each level-1 trigger signal Accept (L1A), extract from the pipeline the information corresponding to the bunch
crossing which gave rise to the L1A and to the two following bunch crossings.
7. Gather the data from many channels in a Readout Driver (ROD), compress them, format them and send them to the Readout Buffer (ROB).
Tasks 1 through 6 are performed by the front-end electronics, which is located on the
detector whereas task 7 is performed by the back-end electronics which is located off
the detector in USA15.