Sierra Wireless, Inc.

Motorola Corporation

Marek Karol Dutkiewicz

David W Russo

Henry Li

Ronald John Vanderhelm

Geoffrey Richard Scotton

Ricardo Lim

Philip J Houghton

J F Beaudoin

A radio-frequency output signal having a specified characteristic is produced using a combination of a calibrated radio unit in which a calibration factor is stored and an uncalibrated modem unit. The calibration factor is input to the modem unit from the radio unit, and the modem outputs to the radio unit a signal of a nominal signal level determined in accordance with the calibration factor. An actual signal level of the signal is measured, and a gain factor within the modem unit is adjusted until the nominal signal level and the actual signal level are substantially equal. A wireless modem includes a calibrated radio unit and an uncalibrated modem unit coupled to the radio unit. A first signal path is provided from the modem unit to the radio unit, and a feedback signal path from the radio unit to the modem unit. The modem unit includes control circuitry for outputting across the first signal path a signal that is nominally of a desired signal level, and for adjusting a nominal signal level of the signal in accordance with information received across the feedback signal path.

Modulation signal calibration between modem and radio using loopback

A low power reduced size serial device protocol translator including a slave controller and detection circuit for detecting start and stop conditions on serial data (SDA) and serial clock (SCL) lines in a serial communication system is described. The start and stop condition detector includes two flip-flops; one for providing a signal that indicates when a start condition has occurred on the SDA and SCL lines and another for indicating when a stop condition has occurred. Each of the flip-flops have their data inputs coupled to a high logic level and their enable input coupled to the serial clock line. The first flip-flop for indicating the start condition has its clock input coupled to the inverse of the serial data signal and the second flip-flop for indicating the stop condition has its clock input directly coupled to the serial data signal. As a result, the first and second flip-flops are only enabled and clocked when either a start or stop condition is occurring, resulting in an extremely low power slave controller detection system. The translator of the present invention translates serial signals between slave and master devices having different protocol types. The translator utilizes sub-protocol signals including length information corresponding to the number of data bits being transmitted to the slave device. The translator uses the length information to gate the serial data from the master device to the slave device. The translator allows for reduction of physical interconnections in a master/slave system in which a master devices resides on a first printed circuit board (PCB) and communicates with slave devices on a second PCB having more than one type of serial communication protocol. In this case, the translator resides on the same PCB as the slave devices thus requiring that only the serial buses corresponding to the master device protocol type be physically coupled across the two PCB's interconnection interface.

Low power serial protocol translator for use in multi-circuit board

An integrated cellular switched modem for enhanced cellular data communication by implementing in DSP or Software all baseband processing normally carried out in a cellular radio transceiver within the processor of the single integrated wireless modem. Adjustments are made to EIA/TIA standards for pre-emphasis, de-emphasis, and companding functions implemented by DSP in order to optimize communication for data.

Optimized companding for communication over cellular systems

A method for reducing the effects of transients on the DC off-set tracking stage and the symbol timing recovery stage in a full duplex or half duplex packet switched data communication system-in which transients occur in the receiver portion of the subscriber when the transmitter portion of a subscriber is keyed ON and OFF is described. The method is dynamically implemented such the DC tracking stage and the symbol timing recovery stage are set in a first 'distortion ready' mode during the time that the transmitter is keyed on and off and is set back to a second 'normal' mode after the transmission event is over. In the 'distortion ready' mode, the symbol timing recovery stage is set in a 'freeze' state such that it makes no further timing adjustments to a decision clock that it generates and the DC off-set recovery stage is set to a narrow bandwidth mode such that it does not track large variations in the DC off-set and amplitude in the received signal. As a result, the Tx/on and Tx/off transients do not upset the decision clock synchronization with the forward channel data stream and the DC off-set tracking stage remains stable.

Method for reducing distortion effects on DC off-set voltage and symbol

In a data communications system including an infrastructure and a subscriber unit operating with a protocol that mandates proactive scanning, a method of power conservation practiced at the subscriber unit including monitoring a registered data channel during an active time period (403), assessing the data channel during the active time period to provide a channel quality value (407), comparing the channel quality to a first threshold (413), assuming a sleep state when the channel quality satisfies the first threshold (417), and scanning another data channel for another channel quality value that satisfies a second threshold when the channel quality does not satisfy the first threshold (415).

Method of power conservation in a data communications system

A data demodulation logic unit (200) and method used therein, adaptable to multiple data protocols, including an arithmetic logic unit (205) that is architecturally optimized to demodulate multiple data protocols under the control of a hardware based state machine (209) that operates in a selectable mode that corresponds to one of multiple data protocols.

Demodulation logic unit adaptable to multiple data protocols

A computationally efficient data decoder that includes a measurement function (18) for providing a channel quality indication, an index function (35) for selecting, responsive to the channel quality indication, a predetermined value representative of a simple machine operation, and decision circuit (27) that weights a decoder decision by performing the simple machine operation.

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Delta, Canada

Marek Karol Dutkiewicz