Detector Frontend Board (Flf) - Agilent Technologies 1100 Series Reference Manual

8 Theory of Operation
On-board Battery
An on-board lithium battery buffers the electronic memory when the module is turned
off.
For safety information on lithium batteries see
337.
Analog Outputs
There are two independent analog outputs (0...1 V full scale). Digital data from the ASIC
is converted into a pulse-width modulated signal (PWM). The PWM signal is then fed to
an amplitude modulator, which precisely turns the reference signal on and off. This signal
then passes to a low-pass filter section.
Interfaces
For detailed information on interfaces, see

Detector Frontend Board (FLF)

Data Acquisition
The FLF board provides circuitry to measure three different physical effects:
• Fluorescence mode: peak value after flash
• Phosphorescence mode: integrated value after flash
• Chemoluminescence mode: amplified signal without flash operation
In parallel to the fluorescence signal the reference signal is acquired to get a
compensation of lamp drift and noise effects. Both signals are amplified and buffered
and routed to the ADC input multiplexer.
The 16-bit A/D-converter performs a conversion of the selected signal and additionally
of the corresponding reference signal and several other signals:
• monochromator positions
• board temperature
• leak sensor status
Then the digital data are polled by the FPGA on the FLM main board to be available
for calculations.
262 1100 Series FD Reference Manual
"Lithium Batteries Information"
"Interfaces"
on page 287.
on page