Mallinckrodt Nellcor N-20 Service Manual page 78

SAMPIR
SAMPRED
Input Signal
Conditioning Signal Gain
Variable Gain
Zeroing RED and Filter
and
DMUX
Current to
Voltage
IR Variable Gain
Conversion
and Filter
Sensor
RED
LED Drive
IR
Output
PWM1
AC + DC
AC Ranging
/ZERO
PWM0
REDAC
Offset Variable Gain
Subtraction and Filter
PWM2
PWM0
Offset Variable Gain IRAC
Subtraction and Filter
AC + DC
RSENS
/ZERO
IR/RED
OFF/ON
LED DIS
PWM0, PMW1, PWM2
N-20 SpO Analog Block Diagram
2
CPU
Figure 9-33
9-49