Abstract: A method and apparatus for converting electronic signals from frequency-division multiplex format into time-division multiplex format while retaining substantially all phase and amplitude information of a band-limited continuous signal. A continuous frequency-division multiplex format signal is multiplied with a first chirp signal having a periodic sequence with period T, a constant amplitude and a phase variation having a non-zero constant amplitude second derivative of said phase variation with respect to time .mu.. A convolution is then performed of said multiplied signal with a convolution filter having an impulse response defined byh.sub.0 (t).times.e .sup.j(.omega..sbsp.0.sup.t-.mu.t.spsp.2.sup./2)wherein h.sub.0 (t) is a function having finite delay greater than T, and .omega..sub.0 is a constant.