ABSTRACT
This chapter explores the ideas underlying Fourier analysis, and – in a straightforward, literal way – translate them into torch. Logic-wise, nothing changes: The only difference is that in general, it will not be possible to represent the signal in terms of just a few basis vectors, like the people did before. Thus, all projections will actually have to be calculated. The output is a one-dimensional vector of Fourier coefficients, of the same length as the input, each holding information about a frequency. The frequency combinations used are not accidental: They represent the encoding of the numbers 0, 8, and 9 in the Dual-tone multi-frequency signaling (DTMF) system, respectively.
