In situ narrow-band calibration of an acoustic receiver

A technique for in situ narrow-band calibration of an acoustic receiver is described. Wide-band Gaussian noise is applied through a random acoustic channel to the receiver and a reference. The resultant output spectra are estimated via Welch's method [1], and the unknown amplitude frequency response is estimated from the ratio of the two spectra. Statistical accuracies of the estimates are investigated. For a specified statistical accuracy, the estimate of the unknown amplitude frequency response is found to require the computation of only one-fourth as many discrete Fourier transforms (DFT's) as the estimates of the two power spectra. That is, where N DFT's are necessary to estimate the two power spectra with a specific accuracy, only N/4 DFT's are needed to estimate, with the same accuracy, the ratio of the spectra.