Abstract: A process for measuring the vapor transmission rate characteristics of a test material by first measuring the vapor transmission through a test chamber and sample material and subsequently repeating the measurement with the test material adjacent the sample material. By subtracting the first measured transmission rate reciprocal from the second measured transmission rate reciprocal, a value is determined which is the reciprocal of the vapor transmission rate characteristic of the test material.

Abstract: A track centering servo pulse noise filter is provided. Prerecorded pulses on a disk track's even and odd half tracks are sensed by the disk's read head, preamplified, DC biased, peak detected, and stored on a FIFO basis into a noise filter comprising two sets of N analog sample and hold cells, one set for the even pulses and one set for the odd pulses. The output of each even-pulse sample and hold cell is input to a summing junction to form an average of the last N pulses. The same is done with the outputs of the odd-pulse sample and hold cells. The two summing junctions are then input to a differential amplifier to form a position error signal to the disk head track centering servo system for keeping the head centered on the track.

Abstract: A system for measuring the height of material in a storage container by generating an incident pulse with a pulse generator and transmitting the pulse through a high impedance transmission line supported in a container. A reflected pulse of opposite polarity is generated at the interface of air and material in the container and is received by a reflected pulse detector which again triggers the pulse generator to continuously monitor the height of the material in the container. The time difference between the transmitted incident pulse and the received reflected pulse of opposite polarity is the indication of the height of the material in the container. A hold off delay disables the reflected pulse detector for a finite period of time so that the reflected pulse detector is not affected by noise signals on the transmission line. If no material is in the container and no reflected pulse of opposite polarity is received, then one automatic start pulse generator retriggers the pulse generator.