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USER MANUAL
Digital Signal Processing (DSP)
For digital signal processing (Digital Signal Processing - DSP) there are three
independent signal processing channels. To each channel belongs a specific
analog-digital converter. This network concept allows analyzing the entering
preamplifier signals simultaneously according to three different feature
complexes.
Channel 1 is the spectrometric channel of the
AlphaGUARD
. Here, there is not only
a signal characterization according to the pulse depth, but also a classification
according to the pulse form. The result of this pulse analysis is a three-dimensional
spectra. Along the X-axis there is a classification of the pulse depth, e.g. of the
adjacent alpha energy. By the Y-coordinate the number of pulses per unit of time
is described. The Z-coordinate stands for the classes of pulse forms.
Figure 2: Block diagram of digital signal processing
Because of this complex pulse characterization, a highly effective differentiation
between real alpha events and different interference effects is possible (for
example: microphonic phenomena).
Signal processing via channel 2 is only effected with higher radon concentrations.
The dimensioning of the used band pass filter grants that the amplitude of the
LOW-
PASS
M
IC
R
OC
O
N
TR
OLLER
S
Y
ST
E
M
ADC 3
DC-INT
SIGNAL
OUTPUT
HIGH-
PASS
BAND-PASS
FILTER
ADC 1
SPECT
ADC 2
AC-EFF
