S/5 Hemodynamic modules
Document No. 800 1008-2
17
Front panel connector and ECG input board
The connector for the 12-lead ECG cable is a green 12 pin Nicolay type connector. 3- or 5-lead
cables with blue connector cannot be connected to this connector. The ECG input board contains
high voltage resistors and a connector for ECG board.
Input protection and filtering
The input protection is implemented with protection diodes, which are connected to analog power
supply voltage and ground. The input filtering for ECG measurement is done with discrete
components. The measured signal is AC-coupled for respiration measurement. The signal from the
respiration supply is AC coupled. There are also the overload protection diodes for respiration
measurement supply.
ECG preamplifiers
The buffer amplifiers are used for each lead except N/RL. The leads off detection is implemented
by measuring the level of the input buffer amplifiers with A/D converter of CPU. The ECG signals are
measured using differential amplifiers.
ECG amplifiers and baseline restoration
The function of the ECG amplifiers and baseline restoration is to amplify the signal and to restore
the baseline of the signal in the middle of the display after the change of the signal level e.g. after
the change of the DC offset voltage.
Pacer detection
Pacer detection has been made by using two slew rate detector circuits. The pacer detection
amplifiers have been realized at the front of the slew rate detectors independently from the ECG
measuring channels.
Respiration impedance supply
The 62.5 kHz sine wave generator is used as the respiration measurement signal supply. Analog
switches are used for connecting the sine wave to the ECG leads to be measured.
Respiration impedance amplifiers
Buffer amplifiers are used in respiration measurement. Analog switches are used for selecting the
measurement leads. There are also additional amplifiers for increasing the respiration signal gain.
Respiration is always measured between R and F, independently on the ECG lead selection.
ECG CPU
The CPU is a 16 bit H8/3048 single-chip microcomputer. It contains 128 kbytes of flash memory
and 4 kbytes of RAM. The clock frequency is 16 MHz.
Summary of Contents for S/5 M-NE12STPR
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