Patent attributes
An apparatus comprises a frequency accumulator to produce a frequency ramp, and a symbol modulator to receive symbols and to add to the frequency ramp frequency offsets representative of the symbols, to produce a modulated frequency ramp for a modulated chirp. The apparatus includes a spreading factor controller to control a roll-over rate of the modulated frequency ramp responsive to spreading factor and frequency bandwidth control signals, to control a spreading factor and a frequency bandwidth of the modulated chirp. The apparatus includes a center frequency controller to control a center frequency of the modulated frequency ramp responsive to a center frequency control signal. The apparatus includes a phase accumulator to accumulate frequency samples of the modulated frequency ramp to produce phase samples corresponding to the modulated chirp, and a vector rotator to rotate the phase samples based on an input vector to produce a modulated chirp.
