Abstract: Transmitters, receivers and associated methods are disclosed for providing phase and amplitude modulation in a carrier-less communication system (e.g., an ultra-wide band communication system). An approximate quadrature signal is provided by delaying the in-phase signal by an amount determined by various criteria, such as the bandwidths of the component signals, minimizing the mean square error between an approximate quadrature signal and the true quadrature signal, and minimizing the auto-correlation function of the in-phase signal.

Abstract: A pulse amplitude modulation (PAM) signal generator that injects a copy of a pulse into the PAM baseband signal prior to frequency upconversion and power amplification. The pulse comprises a function of, or an extra copy of, a pulse in the PAM baseband signal. The pulse injector analyzes the PAM baseband signal for times when a predetermined threshold is exceeded and forms a pulse that is constructed and arranged to reduce the amplitude of the PAM baseband signal to a desired peak amplitude when the pulse is added to the PAM baseband signal.

Abstract: A pulse amplitude modulation (PAM) signal generator that injects a copy of a pulse into the PAM baseband signal prior to frequency upconversion and power amplification. The pulse comprises a function of, or an extra copy of, a pulse in the PAM baseband signal. The pulse injector analyzes the PAM baseband signal for times when a predetermined threshold is exceeded and forms a pulse that is constructed and arranged to reduce the amplitude of the PAM baseband signal to a desired peak amplitude when the pulse is added to the PAM baseband signal. In other embodiments the peak-to-RMS amplitude ratio reducing methods and apparatus used to process PAM signal are adapted for reducing peak-to-RMS amplitude ratios of amplitude modulation signals in polar modulation transmitters. Peak-to-RMS amplitude ratio reduction is performed in the quadrature domain, the polar domain, or both the quadrature and polar domains.

Abstract: Methods and apparatus for optimizing pulses provided by a pulse-shaping filter implemented in hardware. Pulses are optimized and generated by the pulse-shaping filter that are of finite length and meet one or more signal quality criteria, e.g., error vector magnitude (EVM) and/or adjacent channel leakage ratio (ACLR). According to one exemplary embodiment, a first finite length constraint is identified and a second out-of-band power criterion is identified. An error function is defined which measures the distortion of the generated signal relative to a reference pulse modeled after an ‘ideal’ pulse. The error function is minimized to determine optimized pulses, which when used to pulse-shape a communications signal, do not substantially increase in-channel distortion of said communications signal. To avoid the generation of excessive out-of-channel power, minimization is performed subject to a predetermined maximum allowable out-of-channel power condition.

Abstract: This invention controls and modulates switched-mode power amplifiers to enable the production of signals that include amplitude modulation (and possibly, but not necessarily, phase modulation), the average power of which may be controlled over a potentially wide range.

Abstract: The present invention, generally speaking, provides for control of a modulator, such as a polar modulator or conventional linear modulator, to produce high quality RF signals that ramp quickly from a condition of minimal output power to a condition of information-bearing modulation at a specified output power and back down to the condition of minimal output power. Using a polar modulator, for example, it is theoretically possible to perform ramping without degrading the transient measurements beyond the degradation caused by the information-bearing modulation itself. This ideal can be closely approached in practice. Such ramping can be achieved without the need for extensive unit-by-unit calibration on the manufacturing line.

Abstract: This invention controls and modulates switched-mode power amplifiers to enable the production of signals that include amplitude modulation (and possibly, but not necessarily, phase modulation), the average power of which may be controlled over a potentially wide range.

Abstract: The present invention, generally speaking, provides for true multi-mode operation enabling mode switching to be done on-the-fly, in real time. Ramping techniques are provided to fully ramp a communications signal down and then back up inside a guard period while switching from one mode to another so that signal glitches occur only while the signal is ramped down and so can be made negligible. In another aspect of the invention, an advantageous multi-mode communications platform having a polar modulation architecture is provided. Preferably, the platform is based on a multi-mode, predominantly digital, single-chip communications signal processor. A digital, phase-stable, frequency lock loop enables versatile, low-power operation.

Abstract: A technique of processing an input signal having an input signal phase is disclosed. The technique includes determining a number of transitions of the input signal within a period having a start and an end. The technique includes determining a relative beginning phase of the input signal at the start of the period, which includes generating a first reference signal having a first reference signal frequency and a first reference signal phase synchronized with the start of the period, and detecting a first time interval required for the input signal phase to have a first specified relationship to the first reference signal phase. The technique includes similarly determining a relative ending phase of the input signal at the end of the period. The technique includes determining an input signal temporal characteristic from the number of transitions and the relative beginning phase and the relative ending phase.

Abstract: This invention, generally speaking, modifies pulse amplitude modulated signals to reduce the ratio of average power to minimum power. The signal is modified in such a manner that the signal quality remains acceptable. The signal quality is described in terms of the Power Spectral Density (PSD) and the Error Vector Magnitude (EVM).

Abstract: This invention controls and modulates switched-mode power amplifiers to enable the production of signals that include amplitude modulation (and possibly, but not necessarily, phase modulation), the average power of which may be controlled over a potentially wide range.

Abstract: The present invention, generally speaking, provides for control of a modulator, such as a polar modulator or conventional linear modulator, to produce high quality RF signals that ramp quickly from a condition of minimal output power to a condition of information-bearing modulation at a specified output power and back down to the condition of minimal output power. Using a polar modulator, for example, it is theoretically possible to perform ramping without degrading the transient measurements beyond the degradation caused by the information-bearing modulation itself. This ideal can be closely approached in practice. Such ramping can be achieved without the need for extensive unit-by-unit calibration on the manufacturing line.

Abstract: This invention controls and modulates switched-mode power amplifiers to enable the production of signals that include amplitude modulation (and possibly, but not necessarily, phase modulation), the average power of which may be controlled over a potentially wide range.

Abstract: The present invention, generally speaking, provides for true multi-mode operation enabling mode switching to be done on-the-fly, in real time. Ramping techniques are provided to fully ramp a communications signal down and then back up inside a guard period while switching from one mode to another so that signal glitches occur only while the signal is ramped down and so can be made negligible. In another aspect of the invention, an advantageous multi-mode communications platform having a polar modulation architecture is provided. Preferably, the platform is based on a multi-mode, predominantly digital, single-chip communications signal processor. A digital, phase-stable, frequency lock loop enables versatile, low-power operation.

Abstract: A system and method of amplitude modulation is described in which first and second 180 degrees out-of-phase signals are produced and are each amplified by one of two (different amplification factor) non-linear amplifiers. One of the signals is amplified using constant amplification by a first non-linear amplifier to generate a relatively small amplified signal. The other of the signals is modulated using variable amplification by a second non-linear amplifier to generate a relatively larger amplitude modulated signal. The two resulting 180 degree out-of-phase signals are combined, such that the smaller signal effectively cancels out lower level distortion exhibited by the larger amplitude modulated signal. Alternatively, a symmetrical structure can be used for generating AM signals which include phase reversals of the carrier.

Abstract: This invention controls and modulates switched-mode power amplifiers to enable the production of signals that include amplitude modulation (and possibly, but not necessarily, phase modulation), the average power of which may be controlled over a potentially wide range.

Abstract: The present invention, generally speaking, provides a method and apparatus for accurately measuring a communications signal. In accordance with one aspect of the invention, DC offset effects and nonlinearities attributable to a communications amplifier are made spectrally separable from DC offset effects and nonlinearities attributable to the measurement apparatus. Spectral separability may be accomplished, for example, by adding an offset frequency to a local oscillator used by a downconverter of the measurement apparatus. As a result, the signal of interest is moved away from baseband (zero frequency) to the offset frequency. Similarly, other nonlinearities in the video amplifier (such as third order distortion) manifest theselves mostly at harmonics of the offset frequency. Hence spectral separability between the power amplifier characteristics and these nonlinear impairments of the measurement system is achieved.

Abstract: A first amplified signal is produced at a first amplifier, a second amplified signal is produced at a second amplifier, and a differential signal representing difference between the first amplified signal and the second amplified signal is generated at a subtraction unit receiving the first amplified signal and second amplified signal, the differential signal being a final amplified signal having a final modulated amplitude and a final modulated phase.

Abstract: This invention controls and modulates switched-mode power amplifiers to enable the production of signals that include amplitude modulation (and possibly, but not necessarily, phase modulation), the average power of which may be controlled over a potentially wide range.

Abstract: A first amplified signal is produced at a first amplifier, a second amplified signal is produced at a second amplifier, and a differential signal representing difference between the first amplified signal and the second amplified signal is generated at a subtraction unit receiving the first amplified signal and second amplified signal, the differential signal being a final amplified signal having a final modulated amplitude and a final modulated phase.