Editing Orthogonal frequency-division multiplexing (section)

=== Receiver ===
[[File:OFDM receiver ideal.png|center|800px]]

The receiver picks up the signal <math>r(t)</math>, which is then quadrature-mixed down to baseband using cosine and sine waves at the [[carrier frequency]]. This also creates signals centered on <math>2 f_\text{c}</math>, so low-pass filters are used to reject these. The baseband signals are then sampled and digitised using [[analog-to-digital converter]]s (ADCs), and a forward [[fast Fourier transform|FFT]] is used to convert back to the frequency domain.

This returns <math>N</math> parallel streams, each of which is converted to a binary stream using an appropriate symbol [[detector (radio)|detector]]. These streams are then re-combined into a serial stream, <math>\hat{s}[n]</math>, which is an estimate of the original binary stream at the transmitter.