Page "Discrete Hartley transform" Paragraph 7

The DHT can be used to compute the DFT, and vice versa.

For real inputs x < sub > n </ sub >, the DFT output X < sub > k </ sub > has a real part ( H < sub > k </ sub > + H < sub > N-k </ sub >)/ 2 and an imaginary part ( H < sub > N-k </ sub >-H < sub > k </ sub >)/ 2.

Conversely, the DHT is equivalent to computing the DFT of x < sub > n </ sub > multiplied by 1 + i, then taking the real part of the result.