Abstract: Various directional coupler arrangements are disclosed. For instance, an apparatus includes first, second, and third conductive patterns disposed on a substrate. Each of these conductive patterns includes a first end and an opposite second end. Moreover, each of these conductive patterns includes a first protrusion at its first end and a second protrusion at its second end.

Abstract: An apparatus and method for characterizing an amplifier transmitting a band limited signal using a sample of the input signal to the amplifier and a sample of the output signal from the amplifier, where the output signal is sub-sampled. The sub-sampling frequency is chosen such that images of the band limited signal do not overlap. The input signal and the output signal in a polar format are processed to determine characteristics such AM/AM and AM/PM conversion nonlinearities.

Abstract: A method and system for generating noise in a frequency synthesizer are provided. The method includes generating a noise portion of an input signal within the frequency synthesizer and appending the noise portion to a control portion of the input signal.

Abstract: A proxy is utilized to limit the RF bandwidth needed for foreign IP registration. An existing RF log-in procedure causes the proxy to initiate and complete the foreign IP registration procedure with the foreign agent at the RF site where the mobile node is located. The proxy then acts as a locally connected (i.e., direct ethernet connected) device for each IP address for which it is proxying, and thus there is no need to use RF to register a mobile with the active foreign agent. This allows the use of off-the-shelf home and foreign agents to complete the mobile IP architecture, and reduces the RF bandwidth used, since the RF portion of the registration process (the registration between the active foreign agent and the mobile) is reduced.

Abstract: An apparatus, method, and system for voltage controlled oscillator band switching are described. A band switching apparatus may include a reference generation and comparison module, a clock pulse generation module, and a counter and gating module. The reference generation and comparison module may generate a positive signal based on a comparison of a loop filter voltage associated with a voltage controlled oscillator to a maximum tuning voltage and a minimum tuning voltage. The clock pulse generation module may generate a clock pulse in response to the positive signal. The counter and gating module may disable band switching of the voltage controlled oscillator when a lock condition is detected and the loop filter voltage is between the maximum tuning voltage and the minimum tuning voltage. Other embodiments are described and claimed.

Abstract: A method for distributing encryption keys for use in communication systems such as trunked radio communication systems. Group traffic keys are encrypted at a key administrator and passed to a distribution facility for storage and distribution. The distribution facility passes the encrypted group traffic key to communication devices where the group traffic keys are decrypted and used to encrypt/decrypt traffic.

Abstract: A method and system for generating a frequency hopping electromagnetic signal based on a baseband data signal includes a frequency hopping pre-compensator. The frequency hopping pre-compensator determines a frequency hopping pre-compensation signal based on a desired frequency hopping sequence. The frequency hopping pre-compensation signal is combined with the baseband data signal to generate a pre-compensated baseband signal. An RF modulator modulates an RF carrier in accordance with the pre-compensated baseband signal to generate a modulated, frequency hopping RF carrier signal. An amplifier may then amplify the RF carrier signal as desired.

Abstract: A control input signal to select a modulation architecture. When a first modulation architecture is selected based on the control input signal, a time varying and substantially known baseband bias control signal is applied to a bias input of a power amplification module and a time varying and substantially known baseband modulation envelope signal is applied to an input of the power amplification module. When a second modulation architecture is selected based on the control input signal, the time varying and substantially known baseband modulation envelope signal is applied to the bias input of the power amplification module and the time varying and substantially known baseband bias control signal is applied to the input of the power amplification module.

Abstract: An embodiment is a receiver for a communications system that may substantially block unwanted signals in a frequency range to protect the receiver from overload. Simultaneously, the receiver of an embodiment substantially passes a desired signal so that its information may be processed by the, for example, communications system of which the receiver is part.

Abstract: A system and method for automatic roaming in land mobile radio (LMR) systems are provided. The method includes determining a signal quality value for each of a plurality of communication channels in the LMR system and determining if a signal quality level of a current communication channel is below a predetermined threshold. The method further includes automatically switching communication from the current communication channel to one of the plurality of communication channels if the signal quality level is determined to be below the predetermined threshold.

Abstract: A modulation path synchronization apparatus in a polar transmitter includes a modulation path to receive a training waveform, a detector coupled to the modulation path, and a processor coupled to the detector. The detector is to detect a modulated training waveform. The processor is to determine a delay between the training waveform and the modulated training waveform.