Cisco Systems Wireless Networking (Australia) Pty Limited

Cisco Technology, Inc.

Neil Weste

Andrew Robert Adams

John D O'Sullivan

Stephen C Avery

Philip J Ryan

Richard A Keaney

David James Skellern

A wireless local area network system comprises a 5.0+ GHz radio transceiver with two receiving antennas and one transmitting antenna. A transmitter power amplifier output is connected to the transmitting antenna through a 6-8 pole filter to control spurious signal output. Each receiving antenna is fitted with its own low-noise amplifier followed by a simple bandpass filter. Each bandpass filter feeds a diversity switch with a single output to a single receiver. The radio system constitutes a physical-layer (PHY) part of a wireless local-area network.

Diversity transceiver for a wireless local area network

A monolithic radio integrated circuit includes a substrate, a set of one or more analog subcircuits on the substrate, a programmable bias current supply on the substrate coupled to the set to provide bias currents to the analog subcircuits of the set including programmable bias currents to one or more analog subcircuits forming a first subset of the set, and a digital subsection coupled to the programmable bias supply to determine the bias currents supplied to the analog subcircuits of the first subset, such that one or more characteristics of the radio integrated circuit are modifiable by programming the programmable bias supply.

CMOS wireless transceiver with programmable characteristics

A wireless computer data network includes several untethered mobile units that make ad-hoc data connections with an Internet-connected base station using the IEEE-802.11a standard. Each unit includes a radio transceiver fully integrated on a single semiconductor chip. The receiver portion is a double-conversion superheterodyne type, and shares the same intermediate and local oscillator frequencies with a two-stage up-conversion transmitter. Two on-chip synthesizers that each include a voltage-controlled oscillator and phase-locked loop can be operated independently for each conversion stage, or operated in offset mode. External reference frequencies can be injected for voltage-controlled oscillator and phase-locked loop testing, chip characterization, and automatic compensation modeling. Each mobile and base unit can be outfitted with transmit/receive antenna transfer switches, RF-power amplifiers, and low-noise receiver amplifiers to increase operating range.

Wireless computer network including a mobile appliance containing a single chip transceiver

A monolithic transceiver integrated circuit that includes a substrate, a transmitter subsystem of one or more subcircuits on the substrate, and a receiver subsystem of one or more subcircuits on the substrate. Also included is a bias current supply coupled to the receiver and transmitter subsystems to provide bias current. The bias current supply includes a first bias circuit on the substrate coupled to, and to supply bias current to, a first subcircuit of the transmitter subsystem. The first bias circuit includes a first current modulator having a first switch input to indicate that the bias current is to start or stop being supplied to the first subcircuit. The first current modulator is to control the rate of change of supplied bias current in response to the first switch input. The first subcircuit may be a power amplifier. The control of the rate of change reduces oscillator pull in at least one oscillator included in the integrated circuit.

Method and apparatus for reducing oscillator pull in a CMOS wireless transceiver integrated circuit

A wireless local area network system comprises a 5.0+ GHz radio transceiver with two receiving antennas and one transmitting antenna. A transmitter power amplifier output is connected to the transmitting antenna through a 6&#x2013;8 pole filter to control spurious signal output. Each receiving antenna is fitted with its own low-noise amplifier followed by a simple bandpass filter. Each bandpass filter feeds a diversity switch with a single output to a single receiver. The radio system constitutes a physical-layer (PHY) part of a wireless local-area network.

A frequency synthesizer, a calibrator thereof, and an operating controller thereof are described. The synthesizer comprises a main charge pump that drives a voltage controlled oscillator (VCO) through a loop filter. The calibrator includes a second, replica charge pump that can also drive the VCO, but is set up to output only its maximum or minimum analog output control voltage. Since the construction and characteristics of the replica charge pump duplicate the main charge pump, the main charge pump's minimum and maximum analog control outputs can be cloned out to the VCO on demand. A VCO calibration procedure therefore includes switching the VCO to each of its ranges set by a bank of fixed capacitors, and using the replica charge pump to drive the VCO to its minimum and maximum frequency for each range setting. The min-max frequency data is stored in a lookup table, and operational requests to switch to a new channel frequency can be supported with a priori information about which fixed-capacitor range selection will be best. The operating point controller includes a sensor to sense the operating point and a controller that provides a switching input to a switchable bank of capacitors to change the operating point. The change can be determined according to calibration data.

Frequency synthesizer using a VCO having a controllable operating point, and calibration and tuning thereof

A monolithic transceiver integrated circuit that includes a substrate, a transmitter subsystem of one or more subcircuits on the substrate, and a receiver subsystem of one or more, subcircuits on the substrate. Also included is a bias current supply coupled to the receiver and transmitter subsystems to provide bias current. The bias current supply includes a first bias circuit on the substrate coupled to, and to supply bias current to, a first subcircuit of the transmitter subsystem. The first bias circuit includes a first current modulator having a first switch input to indicate that the bias current is to start or stop being supplied to the first subcircuit. The first current modulator is to control the rate of change of supplied bias current in response to the first switch input. The first subcircuit may be a power amplifier. The control of the rate of change reduces oscillator pull in at least one oscillator included in the integrated circuit.

A local oscillator calibrator comprises a main charge pump that drives a voltage controlled oscillator (VCO) through a loop filter. A second, replica charge pump can also drive the VCO, but is setup to output only its most positive or most negative analog output control voltage. Since the construction and characteristics of the replica charge pump duplicate the main charge pump, the main charge pump's minimum and maximum analog control outputs can be cloned out to the VCO on demand. A VCO calibration procedure therefore includes switching the VCO to each of its ranges set by a bank of fixed capacitors, and using the replica charge pump to drive the VCO to its minimum and maximum frequency for each range setting. The min-max frequency data is stored in a lookup table, and operational requests to switch to a new channel frequency can be supported with a priori information about which fixed-capacitor range selection will be best.

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Castle Hill, Australia

Neil Weste