Patent attributes
A method may include generating for transmission a repeating sequence of N constant-frequency pulses of width t seconds at interpulse intervals of T seconds, with each pulse in the sequence having a particular constant phase according to a quadratic phase sequence, which phase is applied to each pulse in a first sense of modulation. The method may further include modulating the phase of echo energy received from one or more objects reflecting the transmitted repeating sequence of N constant-frequency pulses with a second sense of modulation opposite to the first sense of modulation. The method may further include producing from the modulated received echo energy N unique and discrete frequency translations of the received echo energy as a function of range r of the reflecting objects, of magnitude equal to multiples of 1/NT Hz, which may preserve the spectrum of the received echo energy, forming in combination a composite signal frequency spectrum.