Variable phase and frequency pulse-width modulation technique
Phased array systems rely on the production of an exact carrier frequency to function. Reconstructing digital signals by specified amplitude and phase is accomplished explicitly by inducing frequency shifts away from a base frequency implied by phase changes. Shifting the carrier frequency of a digitally controlled phased array while preserving the timing of the individual phase pulses enables more efficient driving of the phased array system when the phase of the drive signals change dynamically in time.
1 . A system comprising:
one or more processors configured to generate a digital electrical signal having a state, wherein the state is determined by comparing a phase difference to a threshold, and wherein the phase difference is determined based on a reference phase of a base frequency cycle and a target phase; and
a phased array of transducers configured to be driven by the digital electrical signal.
2 . The system of claim 1 , further comprising a polynomial spline having a plurality of intervals, and wherein at least one of the plurality of intervals is a base frequency period.
3 . The system of claim 1 , further comprising a polynomial spline having a plurality of intervals, and wherein at least one of the plurality of intervals is a power-of-two count of base frequency periods.
4 . The system of claim 1 , further comprising a polynomial spline having a plurality of intervals, and wherein at least one of the plurality of intervals is a power-of-two fraction of a base frequency period.
5 . The system of claim 1 , wherein the digital electrical signal has a phase angle, and wherein the phase angle is modified by a rolling counter incremented by a value driven by an external environmental monitoring sensor.
6 . The system of claim 1 , wherein the digital electrical signal has a phase angle, and wherein the phase angle is modified by a rolling counter decremented by a value driven by an external environmental monitoring sensor.
7 . The system of claim 1 , wherein the threshold is a value representing an amplitude.