pdp8

02 Dec pdp8

Barron Strachan purchases a pdp8 and develops it for acoustical analysis and accounting. After acquiring a Hewlett-Packard 1/3-octave analog filter set, Bob Strachan and Marcel Rivard construct a sampling system to display third octave band output on an oscilloscope. In 1975, the firm builds an analog-to-digital converter, which allows the pdp8 to interpret the analog output. This converter, christened Third Octave Band Analog to Digital System—or TOBADS for short, functions as a real-time analyzer that calculates reverberation time, equivalent sound levels, 1/3 octaves, exceedance levels and sweeps up to 300 per second for 40 bands.