What must be done in computer applications to measure formant frequencies using Fourier analysis?

In the context of measuring formant frequencies using Fourier analysis, it is important to understand the process involved. Formant frequencies are the resonant frequencies of the vocal tract and are integral to the production of vowel sounds.

The correct approach involves the use of Fourier analysis to convert a time-domain signal (like speech) into its frequency components. Although in some advanced software, displayed data might seem automatic or derived directly from audio input, in many situations, particularly in educational environments or when using basic applications, users often need to precisely measure the formants manually. This is because accurately identifying peaks in a frequency spectrum typically requires careful analysis of the generated Fourier transform.

Manual measurement may involve identifying the specific frequencies where these peaks occur within the spectrum, which are indicative of the formant frequencies. Hence, the idea that they must be measured by hand reflects an understanding of both the limitations and typical practices associated with evaluating audio data in speech research.

The other choices do not align as closely with the measurement process. While it's possible to estimate frequencies or use formulas in theoretical contexts, the direct measurement in practical applications often necessitates a more hands-on approach to ensure accuracy.