Innovative Median Finding Algorithm for Coherent Noise Removal in High Energy Physics Experiments

Several high energy physics experiments suffer from coherent noise affecting their readout electronics. To solve that, the highly successful SAMPA chip is gaining a new successor, the SALSA front-end readout ASIC, which is going to be used in the EIC experiment of the Brookhaven National Laboratory, United States. This new integrated circuit is going to have a common mode noise subtraction, a non-linear filter that is based on finding median values between the many channels of the chip. To guarantee peak efficiency in the filter implementation, this work focuses on the filter's core: the median finder. This part needs to have an efficient algorithm to be implemented in hardware, therefore this paper shows three approaches, two of which are original techniques for digital median finding. These three designs were implemented and verified in TSMC 65nm technology and lastly they were compared in terms of speed, area, power consumption and a preliminary evaluation of error tolerance.