Wireless communication system

1. A method comprising:

directly generating a phase-modulated signal using a direct digital synthesizer (DDS), the phase-modulated signal comprising a sequence of contiguous one-cycle sinusoidal waveforms having a frequency above 50 MHz and a carrier frequency above 50 MHz, wherein phases of the one-cycle sinusoidal waveforms correspond to symbols of a message signal, and wherein the carrier frequency of the phase-modulated signal is equal to the frequency of the one-cycle waveforms;

reducing a bandwidth of the phase-modulated signal using a bandpass filter centered at the frequency of the contiguous one-cycle sinusoidal waveforms;

wirelessly transmitting the phase-modulated signal;

receiving a second phase-modulated signal comprising a second sequence of contiguous one-cycle sinusoidal waveforms;

determining a phase of each of the contiguous one-cycle sinusoidal waveforms of the second phase-modulated signal to recover a second message signal; and

wherein determining the phase comprises:

collecting first and second samples from each of the contiguous one-cycle sinusoidal waveforms of the second phase-modulated signal at respective first and second sampling times occurring when the second phase-modulated signal is monotonic, the second sampling time occurring later than the first sampling time;

calculating a difference between the first and second samples; and

determining the phase based on whether the difference is a positive or negative value.

2. The method of claim 1 , wherein generating the phase-modulated signal comprises:

programming a direct digital synthesizer to generate a one-cycle sinusoidal waveform having a first phase if a corresponding symbol of the message signal is a binary zero; and

programming the direct digital synthesizer to generate a one-cycle sinusoidal waveform having a second phase offset by 180 degrees from the first phase if the corresponding symbol of the message signal is a binary one.

3. The method of claim 1 , wherein wirelessly transmitting the phase-modulated signal comprises transmitting the phase-modulated signal at a data speed equal to the frequency of the contiguous one-cycle sinusoidal waveforms.

4. A system comprising:

a programmable direct digital synthesizer configured to directly generate a phase-modulated signal comprising a sequence of contiguous one-cycle sinusoidal waveforms having a frequency above 50 MHz and a carrier frequency above 50 MHz, wherein phases of the contiguous one-cycle sinusoidal waveforms correspond to symbols of a message signal, and wherein the carrier frequency of the phase-modulated signal is equal to the frequency of the one-cycle waveforms;

a bandpass filter centered at the frequency of the contiguous one-cycle sinusoidal waveforms, the bandpass filter configured to reduce the bandwidth of the phase-modulated signal;

an antenna for wirelessly transmitting the phase-modulated signal;

an edge detector configured to recover a second message signal from a second phase-modulated signal comprising a second sequence of contiguous one-cycle sinusoidal waveforms by determining a phase for each of the contiguous one-cycle sinusoidal waveforms of the second phase-modulated signal; and

wherein the edge detector comprises a sample and hold circuit configured to:

collect first and second samples from each of the one-cycle sinusoidal waveforms of the second phase-modulated signal at respective first and second sampling times occurring when the second phase-modulated signal is monotonic, the second sampling time occurring later than the first sampling time;

calculate a difference between the first and second samples; and

determine the phase based on whether the difference is a positive or negative value.

5. The system of claim 4 , wherein the antenna comprises at least one of: a patch antenna, a microstrip antenna, a helical antenna, and an array of multiple antennas.

6. The system of claim 4 , wherein the programmable direct digital synthesizer comprises:

a waveform lookup table comprising read-only memory configured to store incremental arguments of a sinusoidal waveform and to output a value stored at an address of the waveform lookup table;

an accumulator comprising a counter to increment a stored number by an incremental amount, the stored number corresponding to the address of the waveform lookup table and the incremental amount being determined by a program for generating the phase-modulated signal; and

a digital-to-analog converter for converting a digital signal produced by the waveform lookup table to an analog signal.