REVIEWS OF ACOUSTICAL PATENTS
The Journal of the Acoustical Society of America · 2016
This patent is mainly concerned with airspeed measurements in aircraft, but the patent Claims apply to any vehicle.To achieve maximum accuracy at low airspeeds, an acoustic transmitter is located at one end of the vehicle and a receiver is located at the other end.A repetitive signal is employed, and airspeed is calculated from the delay between transmission and reception.Most of the patent is devoted to the generation and processing of a novel test signal that can be retrieved in the presence of high background noise.The signal is described as "…a continuous wave form having Fourier components of substantially equal amplitude and random phase."Obviously, the phase relationships are not truly random, but the meaning is clear in context.-GLA7,907,743 43.38.Bs ELECTRO-ACOUSTIC TRANSDUCER