[′pəls ¦frē·kwən·sē ‚mäj·ə‚lā·shən] (communications) A form of pulse-time modulation in which the pulse repetition rate is the characteristic varied. Abbreviated PFM.
pulse-frequency modulation
A signal is translated into a succession of constant-amplitude pulses transmitted at a frequency proportional to the amplitude of the original signal. See pulse modulation.