Development of sound analysis equipment for sonar research, part II

Late in 1955 the Deep Water Propagation Committee recommended procurement of 10 sets of sound analysis equipment to be distributed to laboratories working in the field of underwater acoustics. This recommendation was made to be one of the objectives of Contract Nonr-2129. The equipment, including filters for spectrum analysis, was to compute the time integral of the square of the filter output voltages as discussed by Officer and Dietz (1953), WHOI Ref. No. 53-46. In view of the fact that correlation studies are becoming more important it was recommended that the equipment have an optional mode of operation in which it could compute the time integral of the product of two voltages. Multichannel computers were recommended because analysis of data from one hydrophone for one frequency band at one time is much too slow in view of the large amount of data to be processed. Eight channels per computer were chosen because this is the largest number available in standard direct-writing recorders.Undersea Warfare Branch, Office of Naval Research, under Contract Nonr- 2129(00) (NR 261-104)