Thought Technology Ltd. Procomp Infiniti, Руководство по оборудованию

Страница: 24 / 48

Zeroing
Since the MyoScan-Pro uses internal electronic circuitry to perform RMS rectification from within
the sensor, it is sometimes possible to observe slight offsets in sensor reading. This is particularly
obvious with older sensors and at low EMG values (less than 5
μ V). For that reason, it will
occasionally be necessary to zero your MyoScan-Pro sensors. Zeroing is done by connecting the
zeroing plug to the sensor box while recording (plug it where the extender cable connects). With
the zeroing plug on the sensor, the reading should be zero. If your software displays a different
value, usually plus or minus a few microvolts, then you should be able to correct this offset, from
within the software, by using a zeroing function. Keep in mind that each sensor may have
different offset values. If you zero a particular MyoScan-Pro on a given display screen, then you
must always connect the same sensor to the same encoder input when you use that screen.
Remember to remove the zeroing plug after adjusting the MyoScan-Pro sensor’s
offset.
NOTE: Zeroing is not required for the MyoScan sensor, which displays raw signals.
ELECTROCARDIOGRAPHY (EKG)
Sensor Type
To record EKG on the ProComp Infiniti, use an EKG-Flex/Pro sensor. Although a signal can be
detected by applying an EKG sensor, with Triode electrodes snapped on, anywhere on the client’s
chest, using an extender cable and Uni-Gel electrodes greatly enhances the quality of the EKG
signal.
Operating Principle
EKG is similar to EMG: The sensor detects and amplifies the small electrical voltage that is
generated by the heart muscle when it contracts.
Measurement Unit
The actual EKG signal is measured in microvolts ( μ V). Most often, though, the clinically useful
measures are those that are computed from the raw EKG: the heart rate (HR) and its inverse,
the inter-beat interval (IBI). HR is measured in beats per minute (B/min or Bm) and IBI, in
milliseconds (ms).
ProComp Infiniti Hardware Manual 24