Abstract: A transmitter circuit is disclosed for use in a multi-frequency wireless communication system. The transmitter circuit includes an input modulation unit, a phase modulation system, and an amplitude modulation system. The input modulation unit receives at least one signal that is representative of information to be modulated. The phase modulation system is coupled to the input modulation unit and provides a phase modulation on an output signal. The phase modulation system includes a phase detection system and an adjustable power amplifier. The amplitude modulation system is coupled to the input modulation unit and provides amplitude modulation on the output signal. The amplitude modulation system includes an amplitude detection system for providing an output signal to the adjustable power amplifier, and a variable gain amplifier coupled to the adjustable power amplifier.

Abstract: A radio frequency output power control system for use in communication systems is disclosed. The power control system is used for a modulation scheme having a non-constant amplitude envelope and comprises a power amplifier having a power amplifier input for receiving an input signal with a non-constant amplitude envelope, a power control input for receiving a power control input, and a power amplifier output for providing an amplified output signal. The power control system also includes a track and hold circuit for tracking a measured reference power signal that is representative of a modulation of the input signal, and subtraction means for subtracting an output of the track and hold circuit from the measured reference power signal to provide a difference signal that is coupled to the power control input.

Abstract: A transmitter circuit is disclosed for use in a multi-frequency wireless communication system. The transmitter circuit includes an input modulation unit, a phase modulation system, and an amplitude modulation system. The input modulation unit receives at least one signal that is representative of information to be modulated. The phase modulation system is coupled to the input modulation unit and provides a phase modulation on an output signal. The phase modulation system includes a phase detection system and an adjustable power amplifier. The amplitude modulation system is coupled to the input modulation unit and provides amplitude modulation on the output signal. The amplitude modulation system includes an amplitude detection system for providing an output signal to the adjustable power amplifier, and a variable gain amplifier coupled to the adjustable power amplifier.

Abstract: A radio frequency output power control system for use in communication systems is disclosed. The power control system is used for a modulation scheme having a non-constant amplitude envelope and comprises a power amplifier having a power amplifier input for receiving an input signal with a non-constant amplitude envelope, a power control input for receiving a power control input, and a power amplifier output for providing an amplified output signal. The power control system also includes a track and hold circuit for tracking a measured reference power signal that is representative of a modulation of the input signal, and subtraction means for subtracting an output of the track and hold circuit from the measured reference power signal to provide a difference signal that is coupled to the power control input.

Abstract: The present invention provides a miniaturized multilayer microstrip antenna that includes a stack of antenna sub-stacks, a ground element, and a plurality of electrically conductive segments. Each of the antenna sub-stacks includes a pair of substantially parallel outer principal faces. A sandwich of two relatively thin electrically non-conductive substrate elements, separated by a relatively thin electrically conductive layer, extends between each pair of parallel outer principal faces. The electrically conductive layer has at least one void region through which an electrically conductive feedthrough element extends. The feedthrough element also extends between the outer principal faces. The ground element electrically couples the conductive layers of each of the antenna sub-stacks.

Abstract: A power combiner which maintains substantially constant power combining efficiency with variable output power includes a set of unit amplifiers that are coupled by the power combiner. The power combiner includes a first plurality of a quarter wavelength transmission line sections coupled to the output of each unit amplifier. The second end of each one of the first plurality of quarter wavelength transmission line sections are successively coupled by a corresponding second plurality of quarter wavelength transmission line sections, with the succeeding or last one of said unit amplifiers having its quarter wavelength transmission line section coupled to an output terminal. The power combiner permits unit amplifiers in the amplifier module to be switched off in succession as less output power is required while maintaining substantially constant power combining efficiency, and hence substantially constant D.C. to r.f. conversion efficiency.