Abstract: In a system for modulating an RF carrier, the RF carrier is fed through a lowpass filter and phase shifted approximately ?90 degrees. The RF carrier is also fed through a high pass filter and phase shifted approximately +90 degrees. A switch connected to the output of the lowpass filter and connected to the output of the highpass filter, selects and outputs either the ?90 degree phase shifted carrier output from the lowpass filter or the +90 degree phase shifted carrier output from the highpass filter depending on a switching state determined by data bit information received at a data port to produce a BPSK modulated RF carrier. Two such BPSK modulators may be combined using lowpass and highpass filters to form a QPSK modulator. Two such QPSK modulators may be combined with an attenuator to form a QAM modulator.

Abstract: A system for recovering and demodulating a carrier includes a carrier recovery loop and a data detector. The carrier recovery loop receives the carrier as an input and produces a recovered carrier at a frequency approximately equal to that of the carrier. The carrier recovery loop includes a downconverting mixer, a ×5 multiplier, a ×4 multiplier, and a phase locked loop. The downconverting mixer receives the carrier input, and the phase locked loop provides a VCO reference frequency through the ×5 multiplier to the downconverting mixer, which provides a frequency shifted signal. The frequency shifted signal is passed through the ×4 multiplier as input to the phase locked loop. The data detector receives the carrier and the recovered carrier as inputs and uses the recovered carrier to demodulate the carrier and detect I channel data and Q channel data.

Abstract: A digitally controllable nonlinear pre-equalizer system receiving an input signal and generating an output signal, the system including a splitter for dividing the input signal into a first signal path and a second signal path, an attenuator and a time delay element in the first signal path, the attenuator and the time delay element operable to generate a linear signal, a mixer and a vector modulator in the second signal path, the mixer being responsive to a signal from a digital to analog converter coupled to a processor chip providing a digital signal to the digital to analog converter, the mixer and vector modulator operable to generate a nonlinear signal, and a summer for summing the linear signal and the nonlinear signal to generate the output signal.

Abstract: A digitally controllable nonlinear pre-equalizer system receiving an input signal and generating an output signal, the system including a splitter for dividing the input signal into a first signal path and a second signal path, an attenuator and a time delay element in the first signal path, the attenuator and the time delay element operable to generate a linear signal, a mixer and a vector modulator in the second signal path, the mixer being responsive to a signal from a digital to analog converter coupled to a processor chip providing a digital signal to the digital to analog converter, the mixer and vector modulator operable to generate a nonlinear signal, and a summer for summing the linear signal and the nonlinear signal to generate the output signal.

Abstract: A system for recovering and demodulating a carrier includes a carrier recovery loop and a data detector. The carrier recovery loop receives the carrier as an input and produces a recovered carrier at a frequency approximately equal to that of the carrier. The carrier recovery loop includes a downconverting mixer, a ×5 multiplier, a ×4 multiplier, and a phase locked loop. The downconverting mixer receives the carrier input, and the phase locked loop provides a VCO reference frequency through the ×5 multiplier to the downconverting mixer, which provides a frequency shifted signal. The frequency shifted signal is passed through the ×4 multiplier as input to the phase locked loop. The data detector receives the carrier and the recovered carrier as inputs and uses the recovered carrier to demodulate the carrier and detect I channel data and Q channel data.

Abstract: In a system for modulating an RF carrier, the RF carrier is fed through a lowpass filter and phase shifted approximately −90 degrees. The RF carrier is also fed through a high pass filter and phase shifted approximately +90 degrees. A switch connected to the output of the lowpass filter and connected to the output of the highpass filter, selects and outputs either the −90 degree phase shifted carrier output from the lowpass filter or the +90 degree phase shifted carrier output from the highpass filter depending on a switching state determined by data bit information received at a data port to produce a BPSK modulated RF carrier. Two such BPSK modulators may be combined using lowpass and highpass filters to form a QPSK modulator. Two such QPSK modulators may be combined with an attenuator to form a QAM modulator.