Abstract: Calibration methods and structures are provided for wireless communications devices that compensate across a signal bandwidth for relative gain and phase errors between spatial communication channels while utilizing existing transceiver structures and facilitating the use of frequency-domain spatial processing. The methods and structures are directed to time-division duplex (TDD) systems, and are particularly suited to those that incorporate orthogonal frequency division multiplexing (OFDM).

Abstract: The present invention overcomes the problems discussed above by providing a linearizer apparatus for providing a linear ramp modulation for a voltage control oscillator (VCO), including voltage controlled oscillator means (VCO) having input and output terminals, and means for producing the output signal at its output terminal at the output frequency such that the output frequency corresponds to the voltage of a modulated tuning signal applied to the input terminal. A signal division means is coupled to the output of the VCO for producing a divided signal. A glass bulk acoustic delay means is coupled to the signal division means for producing a delayed signal. A first comparison signal generator means is coupled to the divided signal and the delayed signal for producing an IF signal which is proportional to the VCO output signal non-linearities. A reference oscillator means is provided for producing a reference signal.

Abstract: A voltage controlled oscillator is disclosed in a "ring" configuration using two BJTs. The design uses an active feedback topology which eliminates the need for a tank circuit for oscillation to occur. The design also provides for the mixing function to be performed by one of the BJTs.