Eeg machine storage and use of the site should be dry, clean, temperature not too high or too low, the floor to prevent vibration, prevent the dust into the instrument.In when not in use should be a cloth cap.The eeg must have the specialist is responsible for the warehousing and use.In addition, also should pay attention to the following items:
(1), the eeg machine if stop using for a long time, should be electricity, on a regular basis to ward off the moisture and prevent rust, general electricity once or twice a month, every time electrify time an hour or so.
(2), the eeg machine use the ink is dedicated, should not be written in other ink, in case the stylus jams.If discover to there is leakage phenomenon, the ink tank should immediately stop using, handle in time.Pay special attention to not let the ink into the recorder, because of adverse effects on the performance of the recorder.
(3), should pay attention to protect the recording pen, in order to obtain high frequency response, stylus is always made of lightweight, but also cause the strength of the pen is not enough, easy to damage.When use to prevent overload signals to the recorder.
(4) to try to get the baseline, record is in middle position, such as fault found makes stylus slant to the side, should turn off the guide records in time switch, because the pen recorder when partial to the coil current biggest, in the long run will coil overheating or even damage.
(5), be careful not to let the salt water wet electrode wire, line, instrument panel, etc., if the salt water intrusion in, can reduce insulation ac interference caused by disease.
6, often should
monitor the chlorination of the electrodes, and in the use of a chloride processing after a period of time.
The working principle of its main unit eeg amplifier and ecg amplifier basic same, but as a result of brain electrical signal amplitude range of 10-100 mu V, two orders of magnitude smaller than the standard ecg signals, so it requires the amplifier gain is much higher (about 100 db).Because the signal is too weak, the same size of common-mode voltage of electrical detection will be more serious impact, therefore requires eeg amplifier has higher common mode rejection ratio (about 10000:1).The noise should be under 3 mu V.On the power supply ripple coefficient also have higher requirements, when the grid voltage fluctuation of soil 10%, the output voltage change to less than 0.01%, especially the preamplifier level of power supply ripple voltage should be less than 0.5 mV.In order to prevent a possible baseline drift, also has more stringent requirements for electrode, silver - the polarization of silver chloride electrode should be adopted, in order to improve the stability of the polarization voltage.Because eeg electrode is much smaller than ecg electrodes, so it has high source impedance, which requires the amplifier has a higher input impedance (greater than 10 m Ω).
