Abstract: A system is disclosed for transmitting and receiving signals. The system includes the use of a frequency plan table a system for creating the frequency plan table. The frequency plan table relates carrier frequency channels to the operation of a synthesizer and a plurality of programmable frequency dividers in a locked loop. In a transmitter, a first programmable frequency divider accepts a reference signal and produces a comparison signal. A mixer accepts the reference signal and a transmission signal and produces a loop signal. A second programmable frequency divider accepts the loop signal and produces a loop signal having a divided intermediate frequency signal. A phase detector compares the comparison signal and the loop signal having a divided intermediate frequency and produces an output that controls a variable controlled oscillator. The variable controlled oscillator produces a modulated transmission signal.

Abstract: A GmC filter that suppresses unwanted signals generated by a GmC compression stage. The GmC filter utilizes the same compression stage for the decompression stages. By using the same compression stage for the decompression stages unwanted in-band signals generated by the compression stage are suppressed. Further, over all circuitry is decreased, power is saved, and GmC filter design is simplified.

Abstract: Systems for controlling the amplitude of the output signal of a controllable oscillator in a frequency synthesizer are provided. One such system provides a circuit having a controllable oscillator and an amplitude control circuit. The controllable oscillator is configured to generate an output signal having a predefined frequency and a predefined amplitude. The controllable oscillator is also configured with a plurality of operational states that are controlled by the amplitude control circuit. Each operational state of the controllable oscillator defines a particular current bias associated with a distinct amplitude of the output signal of the controllable oscillator. The amplitude control circuit receives the output signal of the controllable oscillator and determines the amplitude. When the amplitude of the output signal of the controllable oscillator is less than the predefined amplitude, the amplitude control circuit provides a control signal to the controllable oscillator.

Abstract: Systems for controlling the frequency of the output signal of a controllable oscillator in a frequency synthesizer are provided. One such system comprises a controllable oscillator and a frequency control circuit. The controllable oscillator is configured to generate an output signal that has a predefined frequency. The controllable oscillator is also configured with a plurality of operational states that are controlled by the frequency control circuit. Each operational state of the controllable oscillator defines a distinct frequency for the output signal of the controllable oscillator. The frequency control circuit receives the output signal of the controllable oscillator and determines the distinct frequency for the output signal that best approximates the predefined frequency.

Abstract: The DC offset compensator compensates DC offsets resulting from interferor self mixing and interferor interaction with even-order nonlinearities. In one embodiment, the DC offset compensator resides in a mobile communication device. A radio frequency (RF) communication signal is mixed with a local oscillator signal (LO) in a direct conversion mixer. The communication signal, at certain times, will have both a communication signal of interest and interferor signals. The interferor signals induce signals in other portions of the mixer circuit, called interferor leakage signals, and the interaction between the two signals causes undesirable DC offsets in the mixer output. The DC offset compensator detects the presence of the interferor signals and provides a compensating signal to the output of the mixer such that the undesirable DC offset signals caused by the interferer self mixing and interferor interaction with even order-nonlinearities in the mixer are compensated out of the mixer output signal.

Abstract: A system is disclosed for interfacing a wireless communication device baseband module and a radio frequency integrated circuit. The system accepts a control signal from the baseband module. The control signal from the baseband module is generally at a first baseband voltage. The first baseband voltage is generally the baseband operating voltage level. The system distributes the control signal, via data latches, to a plurality of local level shifters. The plurality of local level shifters are associated with components of the radio frequency integrated circuit. The local level shifters convert the control signal to a shifted control signal at a second voltage level. The second voltage level is generally the component operating voltage. The shifted control signal may be maintained at the component while the radio frequency integrated circuit is intermittently shutdown. The system eliminates the need to reprogram radio frequency integrated circuit components after the shutdown period.

Abstract: A system for an eight-phase 45° polyphase filter with amplitude matching, where a full eight-phase 45° split may be achieved by tying together the inputs of two offset four-phase 90° phase splitters. Amplitude matching may be achieved by obtaining those inputs from an additional single four-phase 90° phase splitter. The additional phase splitter can distribute power evenly among the inputs of the two offset phase splitters so as to cancel out the occurrence of any uneven power distribution.

Abstract: A subharmonic mixer that has two switching stages is used to improved mixer gain in a direct downconversion receiver. The first switching stage mixes a received RF signal to an intermediate frequency that is one-half the received RF signal frequency. The second switching stage mixes the intermediate frequency to baseband. By connecting the two switching stages in series, current is reused and harmonic content from the first stage is fed into the second stage thereby improving the mixer gain.