A Pulse Time Recorder. A Simple Apparatus for Recording Time Intervals as Ordinates
Svend G. Johnsen · Acta Physiologica Scandinavica · 1945
Summary. The author describes a simple and inexpensive apparatus for recording time intervals as ordinates. The instrument, which is easily adjustable for widely different ranges of frequencies, is most suitable for the determination of relative frequency differences. When absolute time intervals are desired it must be calibrated after each experiment.