Systems and methods for non-invasive respiratory rate measurement

Systems and methods for non-invasive respiratory rate measurement are disclosed. In some embodiments, a system comprises a wearable member including an energy transmitter configured to project energy into tissue of a user. An energy receiver generates a multichannel signal based on a first received portion of the energy. A respiratory rate calculation system includes a pre-processing module to filter noise, a spectrum module, and a respiratory rate processing module.