Advantages and disadvantages of techniques for transforming and analyzing chiropteran echolocation calls

Bat researchers currently use a variety of techniques that transform echolo cation calls into audible frequencies and allow the spectral content of a s ignal to be viewed and analyzed. All techniques have limitations and an und erstanding of how each works and the effect on the signal being analyzed ar e vital for correct interpretation. The 3 most commonly used techniques for transforming frequencies of a call are heterodyne, frequency division, and time expansion, Three techniques for viewing spectral content of a signal are zero-crossing, Fourier analysis, and instantaneous frequency analysis. It is important for bat researchers to be familiar with the advantages and disadvantages of each technique.