Goertzel Algorithm - Original Publication (1958).pdf (Size: 123.05 KB)
The initial publication by Gerald Goertzel's article titled "An Algorithm for the Evaluation of Finite Trigonometric Series" published in The American Mathematical Monthly (Jan, 1958). The algorithm is/was used in DTMF and other technologies for its computational efficiency.
This text can be difficult to find and remains a viable alternative to FFTs (efficiency-wise) even today. While Gerald Goertzel owned more than a dozen patents for similar algorithms, this one was a gift.