Technical noteA new apparatus for time recording in electroencephalographs☆
Review articleOpen access
M. Wolff - No affiliation found
1961/12/01 Short communication DOI: 10.1016/0013-4694(61)90201-2
Journal: Electroencephalography and Clinical Neurophysiology
AbstractAn apparatus is described allowing to record the time at which events occur on the electroencephalogram or other registrations of electrical phenomena, particularly of such taking a long time. For this time recording only one EEG channel is necessary. The principle of the apparatus is based upon the generation of a calibration voltage which is led to two different potentiometer circuits. A synchronous motor every 2 min sends a surge pulse to a step switchgear. The latter picks up a voltage in the first potentiometer circuit which is proportional to the number of the minutes elapsed since the beginning of the test. After 30 x 2 min the step switchgear has returned into its initial position, sending a current pulse to a second step switchgear which picks up a voltage proportional to the number of the hours elapsed from the second potentiometer circuit. If now by means of a rotary switch the calibration pulses and the voltages proportional to the number of the elapsed minutes and hours are led successively at short intervals to the EEG channel, it is possible to read the time elapsed since the beginning of the test by comparing these three deflexions.
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