Service manual

4. BOARD/UNIT DESCRIPTION
Service Manual BSM-4100 4.9
These three boards process the ECG and impedance method respiration signals.
There are two ECG processing circuits on the ECG RESP1 board. One is ECG
analog signals for arrhythmia analysis and screen display which are selectable with
the lead select function. The other one is digital ECG data for 12 lead ECG display
and analysis which is digitized by the A to D converter in the CPU on the ECG
RESP3 board.
The ECG RESP1 board has the impedance method respiration exciter and
detection circuits. These circuits outputs the voltage (respiration signal) which
varies proportionally to the impedance including the electrode contact impedance
between the two electrodes on a patient’s chest.
ECG RESP1, ECG RESP2 and ECG RESP3 Boards
ECG connection cord
Input protection resistors are built in
Excessive voltage protector ESU filter
Cord
side
connector
Feed back
selector
R, L, F
N
C1 to C6
Respiration
carrier
waveform
exciter/detector
Buffer
x 13.45
(R, L, F)
Buffer
x 13.45
(C1 to C6)
I, II composition
Paced baseline
stabilizer
12 lead ECG
(four limbs)
Analog ECG lead
selection
Feed back electrode
selection
Paced baseline
stabilizer
Composed leads
I, II, III,
aVR, aVL, aVF
12 lead ECG (chest)
To polarization voltage
detection circuit (N, R,
L, F, V1 to V6)
Analog ECG
(four limbs)
Analog ECG (chest)
N, R, L, F electrode
contact impedance
detection circuit
Respiration signal
output
ECG/RESP
socket