Abstract: An integrated circuit includes an RF receiver has a direct-conversion down-converter and demodulator architecture with an integrated low noise amplifier (LNA) for operation in a frequency band of interest (cellular) and provisions for an off-chip LNA for operation in a second (higher) frequency band of interest (such as PCS). A baseband processor includes high-dynamic variable gain amplifiers and 7th-order elliptic low-pass filters. The IC also includes a 4 GHz PLL frequency synthesizer and a three wire series interface to external digital baseband circuits, such as a digital signal processor.

Abstract: A method for operating a mobile station includes steps of (A) operating an RF transmitter power detector to obtain an output signal that is indicative of a magnitude of RF power transmitted by the mobile station; (B) processing the output signal to determine a time-varying characteristic of the output signal; and (C) determining a value of the Adjacent Channel Power Ratio (ACPR) from the time-varying characteristic. A further step uses the determined value of the ACPR to control a DC bias current, and therefore the output power capability, of a transmitter amplifier.

Abstract: A method for operating a mobile station includes steps of (A) operating an RF transmitter power detector to obtain an output signal that is indicative of a magnitude of RF power transmitted by the mobile station; (B) processing the output signal to determine a time-varying characteristic of the output signal; and (C) determining a value of the Adjacent Channel Power Ratio (ACPR) from the time-varying characteristic. A further step uses the determined value of the ACPR to control a DC bias current, and therefore the output power capability, of a transmitter amplifier. In one embodiment the time varying characteristic of the output signal includes a frequency spectrum, and the step of processing makes a comparison of the power in one portion of the frequency spectrum corresponding to a desired channel frequency to the power in another portion of the spectrum corresponding to an adjacent channel frequency.