Improved Equipment for Sound Analysis

In many acoustical measurements one often desires to use statistical treatment of large quantities of data. A nearly automatic instrument that analyzes and digitally records signal spectra has been built to facilitate such treatment. Filters, rectifiers, and integrators are operated continuously in parallel from a signal source, and the averaged values read out intermittently to a short‐term storage. Stored data are then serially sampled, expressed as decibels by a high‐speed, linear‐log converter and are recorded on Teletype tape after insertion of sensitivity constants. From the tape directly, or via punched cards, machines perform selecting, averaging, and other statistical processes. The system described is but one of many combinations possible. An example of its performance will be presented. Significant features are its speed, calibration flexibility, and digital read‐out.