DPTC - An FPGA-Based Trace Compression
Journal article, 2020
Recording of flash-ADC traces is challenging from both the transmission bandwidth and storage cost perspectives. This work presents a configuration-free lossless compression algorithm, which addresses both limitations, by compressing the data on-the-fly in the controlling FPGA. Thus it can easily be used directly in front-end electronics. The method first computes the differences between consecutive samples in the traces, thereby concentrating the most probable values around zero. The values are then stored as groups of four, with only the necessary least-significant bits in a variable-length code, packed in a stream of 32-bit words. To evaluate the efficiency, the storage cost of compressed traces is modeled as a baseline cost including ADC noise, and a cost for pulses that depends on amplitude and width. The free parameters and the validity of the model are determined by compressing artificial traces with varying characteristics. The compression method was also applied to actual data from different types of detectors. A typical storage cost is around 4 to 5 bits per sample. Code for the FPGA implementation in VHDL and for the CPU decompression routine in C are available as open source software, both able to operate at speeds of 400 Msamples/s.
data compression
Analog-to-digital conversion (ADC)
Central Processing Unit
data acquisition
VHDL
VHDL
Data compression
Detectors
real-time data acquisition
Bandwidth
lossless compression
open source
Field programmable gate arrays
variable-length code
front-end electronics
field programmable gate array (FPGA)
Encoding
Author
Giovanni Bruni
Chalmers, Physics, Subatomic and Plasma Physics
Håkan T Johansson
Chalmers, Physics, Subatomic, High Energy and Plasma Physics
IEEE Transactions on Circuits and Systems I: Regular Papers
1549-8328 (ISSN) 15580806 (eISSN)
Vol. 67 1 189-197 8876871Subject Categories
Probability Theory and Statistics
Control Engineering
Other Electrical Engineering, Electronic Engineering, Information Engineering
DOI
10.1109/TCSI.2019.2945179