Characterization of digital signal processing in the DiDAC data acquisition system

• Published in: Cytometry (Baltimore); (United States) Vol. 6
• Main Authors: Parson, J.D., Olivier, T.L., Habbersett, R.C., Martin, J.C., Wilder, M.E., Jett, J.H.
• Format: Conference Proceeding
• Language: English
• Published: United States 01.01.1993
• Subjects: 990301 > Information Handling > Data Handling > (1992-); BASIC BIOLOGICAL SCIENCES; COMPARATIVE EVALUATIONS; COMPUTERS; CYTOLOGICAL TECHNIQUES; DATA ACQUISITION SYSTEMS; DIGITIZERS; ELECTRONIC CIRCUITS; EVALUATION; GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; PULSE CIRCUITS; SIGNAL CONDITIONERS 550300 > Cytology
• ISSN: 0196-4763; 1097-0320

A new generation data acquisition system for flow cytometers has been constructed. This Digital Data Acquisition and Control (DiDAC) system is based on the VME architecture and uses both the standard VME bus and a private bus for system communication and data transfer. At the front end of the system is a free running 20 MHz ADC. The output of a detector preamp provides the signal for digitization. The digitized waveform is passed to a custom built digital signal processing circuit that extracts the height, width, and integral of the waveform. Calculation of these parameters is started (and stopped) when the waveform exceeds (and falls below) a preset threshold value. The free running ADC is specified to have 10 bit accuracy at 25 MHZ. The authors have characterized it to the results obtained with conventional analog signal processing followed by digitization. Comparisons are made between the two approaches in terms of measurement CV, linearity and in other aspects.