An Analyzer for Sub-Audible Frequencies

Abstract

The low frequency degenerative analyzer is the latest development in a line of measuring equipment designed particularly for industrial noise and vibration applications. Based upon the principle of selectivity through inverse feedback, which was first described four years ago and which is particularly adapted to low frequency applications, the new Type 762-A vibration analyzer extends the range of accurate measurements down to 212 cycles per second. The instrument is intended primarily to supplement the Type 761-A vibration meter, but is also useful in other applications where a low frequency analyzer, tuned amplifier, or filter is required. Design details and applications of the instrument will be described.