Abstract: An apparatus for biasing a transistor, comprising: a controllable bias generator; a test circuit; a digital Mth order differentiator responsive to an output of the test circuit; and a controller responsive to the digital Mth order differentiator for controlling the controllable bias generator; wherein the test circuit is configured to calculate an Lth order derivative of the transistor's performance.

Abstract: Methods and apparatus are provided for controlling transmitted power in a wireless system. The method includes generating information to be transmitted as a series of signal bursts, with a time interval between successive signal bursts, controlling individually a power level of each of said signal bursts with a power control signal to provide output signal bursts to be transmitted, and asserting a new power value of the power control signal during the time interval preceding each signal burst. The wireless system can be a TDSCDMA wireless system, and the signal bursts can be uplink signal bursts.

Abstract: An apparatus for compensating for variations in loop gain of a phase locked loop as a function of frequency, comprising a correction calculator for introducing a loop gain correction as a function of target frequency of a oscillator controlled by the phase locked loop.

Abstract: An apparatus for biasing a transistor, comprising: a controllable bias generator; a test circuit; a digital Mth order differentiator responsive to an output of the test circuit; and a controller responsive to the digital Mth order differentiator for controlling the controllable bias generator; wherein the test circuit is configured to calculate an Lth order derivative of the transistor's performance.

Abstract: A dual mode transmitter for GSM and UMTS operation is provided. The GSM and UMTS paths share an oscillator and an intermediate frequency stage. Also, with the exception of the final stage of power amplification, the transmitter is provided as an integrated device.

Abstract: A frequency agile voltage controlled oscillator is provided in which amplitude control is performed by digitally controlling the current supplied to the oscillator from a current source (10). The use of digital control means that phase noise performance of the oscillator is not degraded by the introduction of noise from the current source controller.

Abstract: A dual mode transmitter for GSM and UMTS operation is provided. The GSM and UMTS paths share an oscillator and an intermediate frequency stage. Also, with the exceptio of the final stage of power amplification, the transmitter is provided as an integrated device.