Abstract: Accurate position capability can be quickly provided using a Wireless Local Area Network (WLAN). When associated with a WLAN, a wireless device can quickly determine its relative and/or coordinate position based on information provided by an access point in the WLAN. Before a wireless device disassociates with the access point, the WLAN can periodically provide time, location, and decoded GPS data to the wireless device. In this manner, the wireless device can significantly reduce the time to acquire the necessary GPS satellite data (i.e. on the order of seconds instead of minutes) to determine its coordinate position.

Abstract: A charge pump can advantageously include a PMOS transistor that functions as a first current source and an NMOS transistor that functions as a second current source. The transistors can be appropriately sized to provide low parasitic charge injection. Capacitors can function as low impedance voltage sources for rapidly turning on the PMOS and NMOS transistors, whereas switches can be used for quickly turning off the PMOS and NMOS transistors. The capacitors can be charged using a current mirror circuit, thereby facilitating the matching of currents of the transistors and ensuring low power consumption. Alternatively, an operational amplifier can be used in the charge pump to provide high output voltage range and superior current matching.

Abstract: A radar detection technique in a WLAN device can include a short pulse detection technique and a long pulse detection technique that can be performed using multiple receive chains. Short pulse detection is particularly effective when the incoming signal includes one or a limited number of main pulses and some residual pulses. In contrast, long pulse detection is particularly effective when the incoming signal is longer, thereby allowing various characteristics of the incoming signal to be accurately measured.

Abstract: A method and system for pulling a crystal frequency are provided, thereby allowing wireless stations to use less accurate crystal oscillators and dramatically reduce cost. A first frequency offset can be determined using a temperature-based method. This temperature-base method can include detecting a temperature substantially that of the crystal oscillator and then using that temperature to determine the first frequency offset. A second frequency offset using a closed loop frequency estimate-based method can also be determined. This frequency estimate-based method can include synchronizing the crystal frequency to a presumed, accurate frequency of a controlling device to determine the second frequency offset. Both the first and second frequency offsets can be used to pull the crystal frequency. A synthesizer can also be pulled to fine tune a carrier frequency derived from the crystal frequency.

Abstract: A method for correcting influence of frequency offset between a receiver and a transmitter by evaluating training symbols received during a preamble period. The method includes producing, based on at least one long training symbol, a first vector whose first vector angle is indicative of a fine offset between the receiver and the transmitter, producing a fine offset estimate based on the first vector angle, and multiplying, with a signal having a frequency based upon the fine offset estimate, data symbols that are received after the at least one long training symbol is received.

Abstract: A communication system such as an OFDM or DMT system has nodes which are allowed to transmit continuously on one or just a few of the system's frequency sub-channels, while the other nodes avoid putting any signal into those sub-channels. Simple low data rate nodes are allowed to use a small number of sub-channels while more complicated nodes use the remainder, and preferably functionality is provided to ensure that adjacent sub-channels are reliably spaced apart in frequency so that they do not bleed over into one another; to ensure that signals from all nodes arrive at the base station with well-aligned symbol transitions; and to ensure that signals from the various nodes arrive at the base station with similar power levels.

Abstract: A circular filtering system that prevents the problem of inter-symbol interference. The circular filtering system utilizes a buffer memory to store samples of a given symbol and provide only these samples to a linear filter such that the output of the filter, for any given symbol is formed by filtering only samples of that input symbol. Each symbol being filtered independent of other symbols hence eliminating inter-symbol interference caused by filtering. Where symbols are tolerant to a fixed phase shift for each symbol, the circular filtering system can be simplified by reducing the size of the buffer and introducing a multiplexer.

Abstract: A differential amplifier can include input transistors for receiving a differential input signal and an inductor connected to the input transistors. The inductor can protect a voltage supply from radio frequency in the differential input signal. The accuracy of this differential amplifier can be significantly improved by including a bias network. This bias network advantageously allows a bias current in the input transistors to be set independently of a voltage drop across the inductor.

Abstract: A method for detecting a false detection of a packet. The method includes generating a frequency domain representation of a signal, the frequency domain representation including a plurality of complex values each of which is associated with a subcarrier. The method also includes determining an angle for each of the subcarriers, and determining for each pair of adjacent subcarriers an angle difference. The method then includes accumulating the angle differences to produce an accumulated angle, and detecting the false detection based upon the accumulated angle.

Abstract: Countries or regions of the world can have different regulations governing wireless devices. A client product advantageously conforms to any regulatory environment, thereby allowing the client product to operate permissibly in any wireless network. The client product scans all frequencies at a predetermined interval for explicit information on regulation-conformant methods of operation, including frequencies and output power levels. If the client product receives a beacon, then the client product extracts relevant information from the beacon. Based on the relevant information, the client product operates in either the infrastructure mode or the ad hoc mode. On the other hand, if the client product does not receive explicit information, the client product detects other types of information and implicitly derives methods of operation in both infrastructure and ad hoc modes that conform to local regulations.

Abstract: In a wireless local area network (WLAN), receiving or transmitting signals having multiple modulation schemes can require the use of multiple clock rates. Providing these multiple clock rates significantly increases silicon area and power consumption, both of which are highly undesirably in a wireless device. A sequencing interpolator can advantageously reduce the number of clock rates by receiving signals at a first rate and outputting signals at a second rate. The sequencing interpolator can include a multiplexer network that selectively determines which coefficients are applied to certain signals. Coefficients are chosen to ensure that an error in a frequency domain is within a given tolerance. The multiplexer network can be controlled by a counter value. At a predetermined count, the interpolated output signal is discarded and the counter is reset.

Abstract: The use of the magnetic coupling between bonding wires can be advantageously used to transform a differential signal to a single-ended signal. Because bonding wires are very good conductors, this differential to single-ended signal transformation can be performed with minimal signal loss. Moreover, because bonding wires are already part of an integrated circuit package, both system cost and board resources are minimized. The magnetic coupling between bonding wires can also be used to combine the power of a plurality of amplifiers. This magnetic coupling can also be used to provide a single-ended to differential signal transformation.

Abstract: The frequency of a differential circuit can be advantageously adjusted using a switchable inductor. Specifically, the switchable inductor allows a base inductance to be increased by activating one of a plurality of inductor stages. A switch in an inductor stage can be opened to activate that inductor stage. In one embodiment, the switch can be implemented using a PMOS transistor and closing the switch means turning on the PMOS transistor. Advantageously, the switches have non-ideal behavior when closed which may be mitigated by disposing the switch between differential sides of a circuit, thereby providing a more optimal Q for certain applications. Moreover, the switches ensure that the first and second sides of the differential circuit receive an equal resistance to a virtual ground.

Abstract: A method of scaling at a receiver representations of training signals received from a transmitter. The method includes producing a frequency domain representation of at least one long training symbol received at the receiver and a frequency domain representation of a data symbol, and scaling the frequency domain representation of the at least one long symbol based on a largest coefficient in the frequency domain representation to produce a scaled frequency domain representation of the at least one long symbol.

Abstract: The present invention includes a transceiver and a method of operating the same that includes in the transmitter a power control circuit that operates on an analog differential signal containing data packets individually. The power control circuit initially transmits a series of data symbols with known values, periodically strobes the transceiver system for correct power levels and incrementally increases the power level of the transceiver until the optimal gain is reached, without exceeding the maximum output power.

Abstract: A single-ended peak detector is typically used to determine the peak of a differential RF signal. This single-ended peak detector cannot accurately measure the peak because of the common mode component of the RF signal. To solve this problem, a differential peak detector is provided that is capable of accurately sensing the peaks of the differential RF signal by rejecting its common mode component. In one embodiment, the components of this differential peak detector can be duplicated and placed in a mirror configuration, wherein the positive and negative components of the differential signal can be switched for one pair of input terminals. This mirrored differential peak detector can advantageously balance impedances on its inputs and reduce filtering requirements at the output node.

Abstract: A high-speed RF link connects multiple users with individual data appliances to a projection system in a multi-user meeting. The RF link enables high-speed transmission of graphics data in either compressed or uncompressed form to the projection system where application-aware software/hardware carries out any necessary de-compression before display of the graphics data. The RF link also enables high-speed links between multiple users and between one or more users and an external network via a wireline connection to the projection system. A user's capability may also be enhanced by the addition of a local keyboard and a local display.

Abstract: A channel select filter circuit is disclosed using a current-mode transconductance-capacitor (gm-C) architecture, which is tuned by digitally controlled capacitor arrays. The main filter includes at least one transconductor-capacitor (gm-C) filter and a transresistance amplifier. A replica transconductor-capacitor (gm-C) filter and a phase detector are used to establish any phase shift in an input signal, and a state machine adjusts capacitor arrays in the the replica transconductor-capacitor (gm-C) filter and the at least one transconductor-capacitor (gm-C) filter in order to set a cut-off frequency of the channel select filter.

Abstract: A phase selector for selecting a differential output can include two matched transistor circuits. A first transistor circuit can receive a first differential input signal whereas a second transistor circuit can receive a second differential input signal. One of the transistor circuits can be used to dump an output current generated by the first differential input signal to Vdd. The other transistor circuit can be used to steer an output current generated by the second differential input signal to two output lines, thereby providing a differential output signal on the output lines.

Abstract: An antenna is provided with an electronic component or circuit that has a value corresponding to properties of the antenna. A read mechanism reads the value and sets an operational status of a transceiver based on the value. In one embodiment, electronic component is a resistor having a value that identifies the antenna properties. A table may be used to correlate resistor values to different types of antennas or sets of antenna properties. Alternatively, the circuit can be embodied in a microchip that provides a response to a challenge sent by the read mechanism. The response encodes the properties of the antenna. The encoding scheme includes values from the challenge. Alternatively, the response is a code that is indexed into a table of antenna properties. In one embodiment, the antenna is connectorized.