Abstract:
In order to compensate for performance degradation caused by inferior low-cost analog radio component (105) tolerances of an analog radio (100), a future system architecture (FSA) wireless communication transceiver employs numerous digital signal processing techniques to compensate for deficiencies of such analog components so that modern specifications may be relaxed. Automatic gain control (110) functions are provided in the digital domain, so as to provide enhanced phase and amplitude compensation, as well as many other radio frequency parameters.
Abstract:
A dynamically varying linearity system 'DVLS' (102) capable of varying the linearity of a radio frequency (RF) front-end (112) of a communication device (100) responsive to receiving a condition signal indicating a desired mode of operation of a transmitter (112). The DVLS may include a condition signal indicative of the desired mode of operation and a controller (110) that adjusts the linearity of the transmitter responsive to the condition signal. The condition signal may be responsive to a user interface (106). The controller, responsive to the condition signal, may dynamically adjust the operating current of the transmitter.
Abstract:
A transmitter includes a dual mode modulator and an amplifier coupled to the dual mode modulator. The dual mode modulator implements a linear modulation scheme during a first mode of the modulator to produce a variable envelope modulated signal. The dual mode modulator implements a non-linear modulation scheme during a second mode of the modulator to produce a constant envelope modulated signal. The amplifier is biased as a linear amplifier during the first mode of the modulator and is biased as a non-linear amplifier during the second mode of the modulator. A feed-forward connection between the dual mode modulator and the amplifier is used to indicate a change in modulation mode and to adjust the bias of the amplifier. A power of the constant envelope modulated signal is increased such that an operating point of the amplifier remains substantially constant during the first and second modes of the modulator.