Figure 10-11: 300E Sync / Demod Block Diagram - Teledyne 300E Instruction Manual

THEORY OF OPERATION
56V
Bias
Photo-
detector
TEC Control
PHT DRIVE
Thermo-Electric
Programmable
M/R Sensor
Segment
Sensor
E Test Control
Dark Switch
Control
Signal Synchronization and Demodulation
The signal emitted by the IR Photo-Detector goes through several stages of
amplification before it can be accurately demodulated. The first is a pre-
amplification stage that raises the signal to levels readable by the rest of the
Synch/Demod Board circuitry. The second is a and a second variable amplification
stage that is adjusted at the factory to compensate for performance variations of
mirrors, detectors, and other components of the Optical Bench from instrument to
instrument.
170
Dark
Pre
Switch
Amp
E-Test
Generator
Cooler
Control Circuit
E Test A Gate
E Test B Gate
Dark Test Gate
Compact
Measure Gate
Measure Dark Gate
Logic Device
Reference Gate
Reference Dark Gate
From GFC
Wheel
Segment Clock
X1 Reference
From CPU
¸10
via Mother
Board
Phase Lock

Figure 10-11: 300E Sync / Demod Block Diagram

Model 300E Carbon Monoxide Analyzer
Sample
Variable
Gain Amp
Circuits
Phase
x10
Lock
X10 Clock
Loop
Instruction Manual
CO Measure
Signal
&
Conditioner
Hold
CO Reference
Signal
Amplifiers
Conditioner
(x4)
Phase Lock Warning
M/R
Status LED
P/N 04288 Rev: A
Segment
Status LED