Abstract: A frequency hopping system such as a Bluetooth system (300) can reduce the number of RF channels it hops during a normal hopping sequence cycle providing for a Reduced Hopping Sequence (RHS). A communication unit operating in the system such as the Bluetooth master unit (302) determines if any of the RF channels has interference. If any of the channels has interference, the Bluetooth master sends a message to one or more slave units (304, 306) informing them of which channels will be removed from the hopping sequence due to potential interference problems. The units will then use the new RHS for their transmissions, thus avoiding the interference problems (e.g., both avoiding interference in the system's receivers and avoiding creating interference on frequencies that are already occupied by other neighboring systems).

Abstract: A novel and useful apparatus for and method of minimizing the impact of interference on the phase error performance in a phase locked loop (PLL) at integer channels by adjustment of the phase of the interfering signal such that its impact on the reference signal is minimized. Phase control is achieved by use of the digital architecture of the ADPLL and its insensitivity to an arbitrary phase bias introduced between its digitally represented output and reference phase signals. The optimal phase relationship for each integer channel is determined through a calibration procedure in which the phase is swept and the optimal phase is recorded. Before the transmission of a payload on an integer channel, the phase relationship between the output RF signal and the input reference signal is adjusted to the value found to be optimal for that frequency, based on the values previously recorded during the calibration procedure.

Abstract: A novel apparatus and method of linearization of a digitally controlled pre-power amplifier (DPA) and RF power amplifier (PA). The mechanism is operative to perform predistortion calibration to compensate for nonlinearities in the DPA and PA circuits. A predistortion look up table (LUT) stores measured distortion compensation data that is applied to the TX data before being input to the digital to frequency converter (DFC), DPA and PA. The mechanism of the invention takes advantage of the on-chip receiver, which is normally inactive during the TX burst in a half-duplex operation, to demodulate the RF PA output and use the digital I/Q RX outputs to perform calibration of the TX pre-distortion tables. Controlled RF coupling is used to provide a sample of the RF output signal that to the receiver chain. The contents of the predistortion LUT are typically updated during the PA power up or down ramp.

Abstract: A novel apparatus for and a method of estimating, calibrating and tracking in real-time the gain of a radio frequency (RF) digitally controlled oscillator (DCO) in an all-digital phase locked loop (ADPLL). Precise setting of the inverse DCO gain in the ADPLL modulating path allows direct wideband frequency modulation that is independent of the ADPLL loop bandwidth. The gain calibration technique is based on a steepest descent iterative algorithm wherein the phase ADPLL error is sampled and correlated with the modulating data to generate a gradient. The gradient is then scaled and added to the current value of the DCO gain multiplier.

Abstract: A wireless device (100) having an optimum alert sequence definition analyzes its environment, including time and type of incoming call, and selects an appropriate alert signal sequence. A central processing unit (114) included within the device (100) is responsive to a transmitted signal from an external communications device to generate active and passive sonic sensing. The reflected signal received through the microphone (110) and a predetermined set of values or ranges stored in a memory (102) coupled to the central processing unit (114) are used as input for a program of instructions tangibly embodied in a programmable storage device executable by the central processing unit (114). Based upon processing of this reflected signal, the central processing unit (114) determines which alert signal is optimum given the environment.

Abstract: A frequency hopping system such as a Bluetooth system (300) can reduce the number of RF channels it hops during a normal hopping sequence cycle providing for a Reduced Hopping Sequence (RHS). A communication unit operating in the system such as the Bluetooth master unit (302) determines if any of the RF channels has interference. If any of the channels has interference, the Bluetooth master sends a message to one or more slave units (304, 306) informing them of which channels will be removed from the hopping sequence due to potential interference problems. The units will then use the new RHS for their transmissions, thus avoiding the interference problems (e.g., both avoiding interference in the system's receivers and avoiding creating interference on frequencies that are already occupied by other neighboring systems).