3com Corporation

Pacific Monolithics

R2 Semiconductor, Inc.

Ravi Ramachandran

David A Fisher

Lawrence M Burns

Allen F Podell

Chong Woo

Scott William Mitchell

Cory Severson

Sanjay B Moghe

Robert D Genin

Allen Podell

Finbarr J McGrath

Frank Sasselli

Embodiments for at least one method and apparatus of a voltage supply are disclosed. One voltage supply apparatus includes a voltage supply, a plurality of power amplifier (PA) decoupling circuits, and a plurality of power amplifiers. Each PA decoupling circuit is connected to the voltage supply and provides a filtered voltage supply to a corresponding one of the plurality power amplifiers. Each PA decoupling circuit configured to suppress noise of the provided filtered voltage supply below a threshold at one or more selected frequencies, wherein the suppression is provided by the PA decoupling circuit operating in conjunction with at least one other of the plurality of PA decoupling circuits.

Decoupling circuits for filtering a voltage supply of multiple power amplifiers

Embodiments for at least one method and apparatus of a multi-use voltage regulator providing a supply voltage to a power amplifier and at least one other device are disclosed. One method includes generating a plurality of regulated voltage supplies from an unregulated voltage. An output signal power level of the power amplifier is determined. A one of the regulated plurality of voltage supplies and the unregulated voltage supply is selected as a power amplifier voltage supply for the power amplifier based at least in part on the output signal power level of the power amplifier. If the selected power amplifier voltage supply is one of the plurality of regulated voltage supplies, then the selected one of the plurality of regulated voltage supplies is simultaneously provided to the power amplifier and the at least one other device.

Multi-use voltage regulator

Embodiments for at least one method and apparatus of a wireless transceiver are disclosed. For one embodiment, the wireless transceiver includes a transmit chain, wherein the transmit chain includes a power amplifier. The wireless transceiver additionally includes a receiver chain that is tunable to receive wireless signals over at least one of multiple channels, wherein the multiple channels are predefined. Further, the wireless transceiver includes a voltage converter. The voltage converter provides a supply voltage to the power amplifier, and operates at a single switching frequency, wherein the single switching frequency and all harmonics of the single switching frequency fall outside of the multiple channels.

Operating a voltage regulator at a switching frequency selected to reduce spurious signals

In a system that demodulates a frequency modulated signal using a quadrature detector circuit, an apparatus that tunes the output signal to compensate for any offset in the signal includes an offset adjustment circuit and a control circuit. The offset adjustment circuit is operably coupled to the control circuit which may consist of a DAC and a digital logic such as a computer CPU. The control circuit determines a correction signal in response to a sequence of sampled of the system output, and supplies the correction signal to the offset adjustment circuit. The offset adjustment circuit provides an offset correction signal in response to the correction signal, and combines the offset correction signal with the output of the quadrature detector to provide an offset adjusted signal at an output node.

Dynamic adjustment to preserve signal-to-noise ratio in a quadrature detector system

A method and apparatus for performing an operability test on a communications system device such as a cable modem is provided. The testing method comprises the steps of providing a set of output test data to the communications system device being tested, and generating an output signal with the device in a manner that is responsive to the output test data. In the case of a cable modem, the output signal is generated by the modem's modulator. The output signal is then provided as an input to a reflective mixer which generates a reflected signal in response to the output signal and directs it back into the communications system device being tested. The communications device can then use the reflected signal to generate a set of input test data that can be compared to the output test data to check the accuracy of the device's operation. In the case of a cable modem, the reflected signal is demodulated by a demodulator at one or more frequencies, and this demodulated data can then be compared to the output test data. In one case, the testing method is controlled by a computer device running a program of instructions to carry out the aforementioned steps. The computer device can send command signals to the modulator and the demodulator to place them in a test mode. Within this mode, the computer device can command the modulator to generate a particular output signal and command the demodulator to demodulate at certain frequencies.

Method and apparatus for reflective mixer testing of a cable modem

A collision detection method and apparatus which is suitable for use in a wireless CSMA/CD network, or other wireless networks where collision detection is provided. The apparatus includes a detector which detects intermodulation or other mixing products of colliding data transmissions at a station in the network, and a signal processor which indicates collisions between the data transmissions based upon characteristics of the intermodulation products. The system is capable of detecting collisions, both between transmissions from the station on which the device is located and transmissions from other sources, and between two transmissions being received from other sources. The station includes a transmitter having an input for a data packet. Resources coupled to the input add a header to the data packet, the header having characteristics monitored by the collision detector circuitry including a pseudo-random bit sequence. Data transmission signals are supplied to the transmitter in response to the header and the data packet. Thus, collisions occurring during transmission of the header sequence have intervals during which a mismatch occurs between the colliding signal and the data transmission.

Radio based collision detection for wireless communication system

A cascode transistor configuration includes an input terminal for receiving the input signal, an output terminal for outputting the output signal and bass and emitter terminals connectable to ground. Each of a predetermined plurality of common-base heterojunction bipolar transistors (HBTs) has a base coupled to the base terminal, and a collector coupled to the support output terminal. Each of the predetermined plurality of common-emitter HBTs is associated with one of the common-base HBTs. Each common-emitter HBT also has a base coupled to the input terminal, an emitter coupled to the emitter terminal, and a collector coupled to only the emitter of the associated common-base HBT.

Segmented cascode HBT for microwave-frequency power amplifiers

A feedback circuit couples a base amplifier output to the amplifier input for feeding back a portion of an amplified input signal. The feedback circuit includes an inductor coupled in series with a variable resistance. The variable feedback resistance is provided by a feedback FET having a gate for receiving a control signal for varying the resistance between the source and drain. The gain of the base amplifier is determined over the predetermined frequency range by the combined impedance of the inductor and resistance. The base amplifier is a field-effect transistor (FET). The feedback inductance is taken from a portion of a coil coupling the drain of the base FET with an output terminal.

Gain-tilt amplifier

A loaded Lange coupler embodied as an integrated circuit includes interdigitated strip conductors and lumped-element capacitors. The two interdigitated strip conductors couple the input and direct ports together, and the isolated and coupled ports together. A capacitor extends between each of the input and coupled ports and the isolated and direct ports. Further, a capacitor extends between each of the midpoints of the strip conductors and ground. This coupler is formed as an integrated circuit in which the current-to-ground capacitors are substantially in line between opposite port pairs and the strip conductors extend around these capacitors.

Growing community of inventors

San Jose, CA, United States of America

Ravi Ramachandran