Fukuda CardiMax 2, Service Manual, Page: 40 / 124

2-6
Chapter 2 Operational Description Operational Description
ECG Input Unit
The functional block diagram of the ECG input unit is shown below.
The ECG signal input from the patient input connector passes through the input protector and enters the differential
amplifier. Here, the signals of the right hand, left hand, chest 1 to chest 6 are differentially amplified with the left
foot signal.
The output of the differential amplifier is converted to a digital signal by the respective A/D converter. The
digitalized ECG signal is transferred to the CPU board by SPI communication.
The ECG AMP block is electrically isolated by photo isolater and isolation power.
Operation Panel/Touch Panel Unit
The block diagram of the operation panel/touch panel unit is shown below.
A resistive touch panel is used.The touch panel is a 7-inch 4-wire type, and transmits the data to the CPU by the touch
controller with I2C I/F.
The key data of operation panel is transmitted to the CPU with I2C I/F.
The statuses of AC power supply and battery are indicated by the key sheet LED.
bl5932
CPU Block
A/D Converter
Differential
Amplifier
Input
Protector
E25F
Unmount
RF
F
C9
C8
C7
C6
C5
C4
C3
C2
C1
L
R
Isolation
Power
+5V
+5VF
+2.5VA
-2.5VA
100KHz
SPI
SPI
Photo Isolator
20bit A/D
AMP Block
Patient
Input
Connector
12bit A/D
ch1
bl5933
LCD
TP controller
Key Panel
LED
Key Sheet
CPU Board
Touch Panel
CPU