GE B30 Technical Reference Manual page 53

SpO2
Probe
Ambient reduction
Preamplifier:
Current-to-voltage type
Bipolar/single-ended modes
Adjustable gain
Figure 23
Red and infrared channel separation
It is possible to multiplex the detector signal to four different channels depending on the
content of the signal. The detector signal must at least multiplex into infrared and red signals.
Other channels are e.g. for diagnostic purposes.
Serial communication
An RS485 type bus driver makes the serial communication between the module and the frame.
The data transmission rate is 500kbps.
Amplifier:
Gain = 2
DE-MUX
Analog
Pulse oximetry measurement block diagram
LED Driving circuit 1 LED Intensity adjustment 1
LED Driving circuit 2 LED Intensity adjustment 2
LP
Gain=7.5
LP
Gain=7.5
LP
Gain=7.5
LP
Amplifiers
Digital
E-PSM(P)W module introduction
LED ON/OFF control 1
LED voltage indication 1
LED current indication 1
LED ON/OFF control 2
LED voltage indication 2
LED current indication 2
Oximeter channel 1
DC-
suppression
Oximeter channel 2
DC-
suppression
Oximeter channel 3
DC-
suppression
Oximeter channel 4
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