Ericsson Gmbh

Telefonaktiebolaget Lm Ericsson (Publ)

Rodney A Dolman

Paul Wilkinson Dent

Ross W Lampe, Jr

Charles Gore

Gerard James Hayes

Antonio J Montalvo

Ronald D Boesch

Terrence Edward Rogers

Russell Evans Winstead

Xue-Song Zhou

John T Gillette

Jeffrey Scott Kemp

Jacob Filip Mannerstrangle

A transceiver includes a transmitter and a homodyne receiver, wherein the receiver is used to process both antenna-received and antenna-reflected signals. Thus, during a receive mode, for example, the receiver downconverts antenna-received signals to baseband signals, which are then processed to recover receive signal information. Then, during a transmit mode for example, antenna-reflected transmit signals are fed back to the receiver, which is retuned to the desired transmit frequency, and thus downconverts the reflected transmit signals to baseband signals. These baseband signals are then processed to obtain a characterization of impedance mismatch between the transceiver's transmitter and the associated antenna. An adjustable matching network disposed in the transmit signal path thus may be adjusted based on the characterization to reduce the mismatch. Such configurations may be used with either single-band or multi-band embodiments of the transceiver, and the transceiver may be used in both TDMA and CDMA communication systems.

System and method for adaptive antenna impedance matching

A method of broadcasting commercial FM services in a digital format in at least one bitstream comprises time-division multiplexing the bitstream(s) into one or more channels comprising a data frame, and frequency modulating the data frames around a single carrier frequency into a commercial FM broadcast signal. The modulation may comprise GMSK or 8-PSK, and multiple data frame types may be interleaved. The signal is transmitted on a commercial FM broadcast station such that substantially the entire spectrum of the transmission comprises the digital data frames. The bit rate(s) of the digital bitstream(s) may be monitored, and the bitstream(s) may be reallocated to channels in the data frames based on changes in the bit rate(s). Analog and digital formats may be broadcast simultaneously on non-adjacent commercial FM broadcast carrier channels. A receiver is operative to extract and decode content from a digital format FM broadcast signal.

Digital format U.S. commercial FM broadcast system

A mobile radio telephone having a simplified architecture including a reduced number of integrated circuits and a reduced number of RF connections. A dual band, dual mode mobile phone can be constructed using either a single crystal reference oscillator or two crystals such that alternative symbol rates, channel spacings, or transmit/receive duplex spacings can be achieved.

Method and apparatus for generating a plurality of reference frequencies in a mobile phone using a common crystal reference oscillator

Simplified reference frequency distribution in a mobile phone

A spring member internally mounted within an electronic device, such as a radiotelephone, serves both as a mechanical device for urging a flip cover to an open position and as an antenna for receiving and/or transmitting wireless communications signals.

Mechanical spring antenna and radiotelephones incorporating same

A mobile radio telephone having a minimized tuning bandwidth, based on limiting intermediate frequencies at the highest and lowest expected receive frequencies in each band. A dual band, dual mode mobile phone can be constructed which maintains or improves intermodulation performance using fewer battery cells without additional circuitry.

Tuning bandwidth minimization for low voltage dual band receiver

A transceiver which generates transmit and receive channel frequencies using a single crystal reference oscillator is disclosed. A first and second local oscillator is connected to the crystal reference oscillator. A first down converter is connected to the first local oscillator which mixes a receive signal with a first local oscillator frequency to produce a first intermediate frequency signal. The first intermediate frequency signal is then amplified and filtered and applied to a second down convertor which mixes the filtered first intermediate frequency signal with a second local oscillator frequency to produce a second intermediate frequency. A transmit frequency offset is then generated using the second local oscillator frequency. A transmit frequency generator generates a transmit frequency using the transmit frequency offset and the first local oscillator frequency.

Transmit signal generation with the aid of a receiver

A simplified structure is disclosed for a dual-band, double-conversion superheterodyne receiver. All mixer-injection signals are generated by combining the outputs of two phase-locked frequency synthesizers driven by a single reference oscillator. The output of one synthesizer injects the receiver's second mixer, which converts signals from the first intermediate frequency to the second intermediate frequency. The output of the other synthesizer has two uses: (1) it provides first mixer injection needed to tune the receiver to a primary band, and (2) it is mixed with the output of the first synthesizer to provide the first mixer injection needed to tune the receiver to an alternate band.

Dual-band radio receiver

A communications apparatus for coupling a transmitter and receiver for duplex transmission is disclosed. The apparatus comprises a transmitter with a transmit power amplifier, a receiver with a receive filter, and a circulator with a plurality of ports, wherein the transmit power amplifier is connected to a first port of the circulator and the receiver filter is connected to a second port of the circulator. An antenna is demountably connected to a third port of the circulator. A switch alternately connects a load and the receiver to the second port of the circulator, wherein the receiver is connected to the second port of the circulator during reception of signals and the load is connected to the second port of the circulator during transmission so as to absorb power reflected by the antenna.

Circulator usage in time division duplex radios

A high dynamic range receiver IF system using limited dynamic range IF filters is disclosed. A variable gain amplifier amplifies a first IF signal. The amplified first IF signal is then applied to an image suppression mixer for suppressing an image component of the amplified first IF signal to provide adequate image suppression for a radio system, wherein the image suppression mixer outputting an image suppressed second IF signal. An active bandpass filter then filters the unwanted components from the second IF signal. The filtered signal is then hard limited in a limiting amplifier which outputs a limited IF signal. A logarithmic detector then provides a received signal strength indicator.

Receiver IF system with active filters

Reduction of transmitter exciter chain generated noise from the receive bank of a portable/hand-held duplex transceiver is achieved using a high output power, low-noise voltage-controlled-oscillator (VCO) in the transmitter exciter chain. Using this high-power, low-noise oscillator as the RF source in the transmitter exciter chain precludes the need for the conventional buffer/driver amlplifier stage and an associated inter-stage noise filter. Elimination of buffer/driver stage components and bulky inter-stage noise filter components allows complete integration of transmitter exciter chain components resulting in reduced size and cost.

Method and apparatus for reducing receive band transmitter-chain noise

An inductive element having a selectable inductive value is connectable to a differential circuit. The inductive element is formed of transmission lines, and the inductive value of the inductive element is altered by trimming away portions of the transmission line while maintaining the inductive element in balance with the differential circuit.

Growing community of inventors

Cary, NC, United States of America

Rodney A Dolman