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European X-Ray Spectrometry Conference (EXRS 2006)
Paris (France)

Adaptive Matched Filtering Of XRF Detector Signals
G. Georgiev, I. Peev
INRNE - BAS, Bulgaria
Matched filtering was proposed back in 1967 by V.Radeka and
N.Karlovac* as 'perfect' solution for white noise cancellation.
Analog implementations are not practical due to number of reasons,
some of which are:

  • unstable components, especially the analog multiplier
  • extremely tight tolerances required

On the other hand, digital filtering is known as extremely stable.
The whole presentation (.pdf file 592KB).

(*) V. Radeka and N. Karlovac. Least-square-error amplitude
measurement of pulse signals in presence of noise. Nucl. Instrum.
Methods 52: 86'92, 1967.


NEC 2005
XX-th anniversary International Symposium on Nuclear Electronics and Computing.
BULGARIA, VARNA, 12-18 September, 2005

ADC/MCA Module with PC Interface
G. D. Georgiev, I.T. Peev
INRNE - BAS, Bulgaria
The well-known Gatti correction method to reduce the DNL of a regular SAR ADC is implemented using the latest technology. The original approach in creating this ADC, combined with Multi-channel analyzer and flexible PC interface (Serial, USB or Ethernet) gives a compact, reliable and useful instrument. - the whole presentation (.pdf file 1.4MB)

European X-Ray Spectrometry Conference (EXRS 2004),
Alghero, Sardinia (Italy)

A well-known idea of sliding scale correction to overcome DNL (differential non-linearity) of an ADC has found it's new implementation using the advantages of CPLD (Complex Programmable Logic Device), fast ADC and precise DAC. In order to increase the throughput of the whole system, the next stage - an MCA (Multi Channel Analyzer) is implemented in the same CPLD chip and the spectra are captured into a dual-port memory. Finally, a PC compatible interface (RS232 or USB) is used to transfer the captured data and makes it possible to monitor and control the process in real time. Laboratory results show that this device is capable of performing more than one million measurements per second (PHA mode) without adding any dead time and transferring the collected 2k/4k-channel spectra to a PC several times per second. - the whole presentation (.pdf file 1.2MB)