Fukuda Denshi DSL-8001, Service Manual

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ECG Assembly Board Block Diagram
ECG Block
Respiration Block
ECG Assembly Board Circuit Description
ECG assembly board consists of ECG input protective circuit, lead OFF detection circuit,
measurement amplifier, A/D converter, and MCU which controls them and transmits each electrode
potential to CPU board in serial communication.
Impedance respiration energizes a weak high-frequency current between ECG as a carrier signal
and detects the carrier signal amplitude change which corresponds to chest impedance change
caused by respiration. The high-frequency signal inputted into the respiration circuit is rectified to a
waveform by passing through a bandpass filter, and then transmitted as an A/D converted signal to
the CPU board in serial communication.
z CPU
ATMEGA16 (ATMEL, 11.0592MHz RISC Processor) is used as CPU. The CPU receives ECG and
RESP signals and transmits data to CPU board. Also, the CPU has 16 Kbytes flash memory, 512
bytes EEPROM, 1 Kbyte SRAM, 8-channel, 10-bit ADC, and SCI (Serial Communication Interface)
inside.
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