GE MAC 1200 Servicing Instructions page 71

GE Medical Systems MAC 1200 V 1.2 Page 69
Information Technologies 227 492 21 RevF
e for all leads, gain adjustment in four steps:
40-20-10-5 mm/mV
e with active muscle filter (low-pass characteristic) 3-dB drop of the amplitude frequency response
at approx. 40 or 20 Hz
® with active AC line filter detection and compensation of periodic 50 or 60 Hz frequency
components (depending on recorder model) attenuation >40 dB
* non-linear distortion below values specified in IEC and AHA recommendations
@ coincidence error limits between any two channels +0.5 mm
e detection of pacer pulses in V2 or other V leads and marking in all channels for signals referred
to patient input:
duration > 0.1 ms, amplitude > 5 mV
e noise in the signal transmission path below values specified in IEC and AHA requirements:
< 2.5 uV rms
e common-mode rejection for 50 or 60-Hz signals (depending on recorder model) with AC filter
switched on >140 dB
ECG calibration
automatic recording of a defined voltage step, valid for all channels
e calibration voltage, referred to ECG signal input: | mV
calibration pulse width on recording depends on paper speed
25 mm/s: 5mm
50 mm/s: 10mm
5 mm/s: mm
Automatic ECG gain adjustment
The gain automatically adapts to the incoming signal. The maximum amplitude of the lead group or
of all leads determines the gain setting.
® automatic adjustment range 5 to 40 mm/mV
e amplitude range (6 channels) 18 to 31 mm
Baseline
automatic adjustment of the baseline to the optimal recording range, in dependence of the signal
amplitude