A REPORT OF RESEARCH UNDER
CONTRACT N5ori-76 PROJECT ORDER II
AUDIO CHARATERISTICS OF COMMUNICATION EQUIPMENT
Submitted by the
Staff of the
Electro-Acoustic Laboratory
This research was initiated at the Electro-Acoustic
Laboratory under Contract OEMsr-658. That contract
between the Office of Scientific Research and Devel-
opment and Harvard University was supervised by NDRC
Section 17.3. The work has been completed under Con-
tract N5ori-76 between the Office of Research and In-
ventions, U. S. Navy, and Harvard University.
PSYCHO-ACOUSTIC LABORITORY
HARVARD UNIVERSITY
CAMBRIDGE 38, MASSACHUSETTS
PNR-6 FEBRUARY 1 1946
This report covers the analysis of communications audio with respect to Signal to Noise ratio in the expected environment. Although we are not expecting to be listenting to signals in a 4 engine bomber at 35,000 feet, the figures and charts supplied can be used to judge a system where most of the noise is from the communications link itself ie either QRM or QRN.
Section F is most interesting and contains charts of Articulation Index vs low/High cutoff and frequency bands of equal contribution to Articulation Index. The other Sections are of less direct interest but do provide some backgound.
Note that sections K and M have been declassified!