Abstract: A system for transmitting and receiving data is provided. The system includes a direct-conversion receiver that receives a signal modulated on a carrier frequency signal. The direct-conversion receiver includes one or more subharmonic local oscillator mixers. A local oscillator is connected to the direct conversion receiver, and generates a signal having a frequency equal to a subharmonic of the carrier frequency signal. A transmitter is connected to the local oscillator, which uses the local oscillator signal to transmit outgoing data.

Abstract: A system provided for controlling an output frequency of a voltage controlled oscillator relative to a reference frequency. A method includes the steps of detecting a phase error between a divided output of the voltage controlled oscillator and the reference frequency, pumping a frequency control input of the voltage controlled oscillator with the phase error and adjusting a pumping gain based upon a magnitude of the frequency control input to the voltage controlled oscillator. This apparatus includes a phase detector adapted to detect the phase error between the divided output of the voltage controlled oscilator and the reference frequency and a charge pump adapted to pump the frequency control input of the voltage controlled oscillator with the phase error. The apparatus also includes a gain controller adapted to adjust the pumping gain based upon the magnitude of the frequency control input to the voltage controlled oscillator.

Abstract: A system for controlling an output frequency of a dual-input voltage controlled oscillator relative to a reference frequency is provided. The method includes the step of coupling a first tune control signal to a first input of the dual-input voltage controlled oscillator. The method further includes the steps of dividing the output frequency of the dual-input voltage controlled oscillator by a value substantially equal to a second tune control signal, comparing a phase of the divided output frequency with a phase of the reference frequency and coupling a phase difference of the compared phases to a second input of the dual-input voltage controlled oscillator.

Abstract: A BALUN circuit comprising a lead network coupled to the positive phase output of a differential power amplifier, a negative phase output coupled to the negative phase output of the differential amplifier, and a delay element coupled in series with the lag network. The output of the lead network and the delay element are combined to form a single-ended output. The lag and lead networks may adjust the output impedances of the positive and negative phase outputs so that the output impedance of the single-ended output is set to a desired value. In one implementation, selected components of the lag and lead networks, and the delay element, comprise printed elements.

Abstract: A system provided for controlling an output frequency of a voltage controlled oscillator relative to a reference frequency. A method includes the steps of detecting a phase error between a divided output of the voltage controlled oscillator and the reference frequency, pumping a frequency control input of the voltage controlled oscillator with the phase error and adjusting a pumping gain based upon a magnitude of the frequency control input to the voltage controlled oscillator.

Abstract: A non-linear power amplifier for amplifying a constant envelope phase modulation component of a modulation signal and combining an amplitude envelope component of the modulation signal into the amplified constant envelope phase modulation component and method for performing the same. The power amplifier receives a constant envelope phase modulation signal and transmits the signal through a pair of amplifier stages which are impedance matched together. The first amplifier stage has a fixed gain which drives an impedance load and, in turn, the second amplifier stage. A variable resistance device is connected between a base of an amplifying transistor in the second amplifier stage and electrical ground for variably controlling the gain of the second amplifier stage by variably controlling the base-to-ground resistance of the amplifying transistor in the second amplifier stage.