Service manual

4. BOARD/UNIT DESCRIPTION
4.12 Service Manual BSM-4100
This board consists of the following blocks.
• Differential amplifier block for the electrical signals detected by the photodiode
when the red LED and infrared LED in the SpO
2
probe alternatively transmits the
lights to the subject
• Red and infrared related signals separator block
• Pulse wave amplifier block
• Time division multiplexed analog signal block
• LED drive current control block
• Probe ID recognition block
• Probe failure detection block
NK SpO
2
Board and Nellcor SpO
2
Module
NK SpO
2
Board
SpO
2
probe
Differential amp
Pulse wave amp
LED driver
Probe ID
recognition
Probe failure
detector
R-IR separator
Time division
processor
LED control
Serial to parallel
data converter
for control signals
Parallel to serial
data converter for
status signals
Time division multiplexed
analog signal output
Light intensity control
Gain control
SpO
2
status signal
The module covers all the abovementioned blocks in the NK SpO
2
board. The
module sends the SpO
2
data and status data to the DPU board through the
motherboard by serial data communication.
Nellcor SpO
2
Module