Non-contiguous spectral-band modulator and method for non-contiguous spectral-band modulation

A method for generating a waveform for transmission within two or more subbands of a non-contiguous spectrum, the method comprising:

• selecting, with an input symbol tuple, a sequence of phase values, each value of the sequence of phase values representing an instantaneous frequency of a waveform for a signal with a power spectral density substantially constrained to the non-contiguous spectrum;
• accumulating the values of the sequence of phase values to generate a phase-sample sequence representing phase samples of a transmit waveform;
• performing an exponentiation on the phase-sample sequence to generate a constant modulus signal sequence;
• and
• multiplying the constant modulus signal sequence by a weighting sequence to generate an output signal sequence to cause the output signal sequence to be constrained to a region in a complex plane while in a subband or to have a controlled signal trajectory during transitions between subbands.

A field-programmable gate array (FPGA) configured for non-contiguous spectral-band modulation, the FPGA configured to:

• map an input symbol tuple to a sequence of phase values, each value of the sequence of phase values representing an instantaneous frequency of a waveform for a signal with a power spectral density substantially constrained to the non-contiguous spectrum;
• accumulate the values of the sequence of phase values to generate a phase-sample sequence representing phase samples of a transmit waveform;
• perform an exponentiation on the phase-sample sequence to generate a constant modulus signal sequence;
• and
• either:
• multiply the constant modulus signal sequence by a weighting sequence to generate an output signal sequence to cause the output signal sequence to be constrained to a region in a complex plane while in a subband or to have a controlled small signal trajectory during transitions between subbands;
• or
• filter the constant modulus signal sequence to further constrain the output signal sequence to the non-contiguous spectrum to generate an output signal sequence.