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: 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 method and apparatus for separating and removing distortion from interfering co-channel signals and suppressing adjacent-channel interfering signals of the Gaussian Minimum-Shift Keyed (GMSK) or other MSK type with filtering structures that exploit the cyclostationarity of the received GMSK or other MSK signals in order to accommodate a greater number (or the same number, but with greater quality) of transmitted signals received by one or more antennas than can be accommodated by existing filters. The parameters in these filtering structures are adapted by either of two adaptation apparatus that exploit both the known training sequence that is transmitted in most wireless communications systems, and the constant modulus property exhibited by each of the transmitted GMSK or other MSK signals.

Abstract: A processor and method for extracting or estimating directions of arrival of signals from a received data vector x(t) which has been corrupted by interfering signals and noise is described. The processor extracts signals by forming the scalar product of x(t) and a weight vector which is chosen such that the spectral self-coherence or conjugate spectral self-coherence of the processor output is maximized. The processor estimates the directions of arrival of signals by spectral self-coherence-selective performance surfaces for maxima.

Abstract: A method and apparatus for spatial multiplexing of spectrally overlapping communications signals which does not require use of a training signal, computationally intensive direction-finding methods, or antenna calibration is presented. An adaptive antenna array at a base station is used in conjunction with signal processing through self coherence restoral to separate the temporally and spectrally overlapping signals of users that arrive from different specific locations within the locale and to mitigate multipath fading and shadowing at the base station and, by reciprocity, to transmit directively to minimize interfering signals arriving at the mobile (or portable or stationary) units and to mitigate multipath fading and shadowing at the mobile units. The radiation pattern of transmitted signal is matched to the adapted reception pattern of the signal received at the base station.BACKGROUND OF THE INVENTIONThe Government has rights in this invention pursuant to Grant No.