Abstract: Methods and apparatus for determining an available FM frequency channel for interfacing with FM modulated output signals from a wireless device are described herein. A SPS receiver, such as a GPS receiver, can determine its position based on conventional techniques. The SPS receiver can determine one or more available FM channels over which audio output may be transmitted. The SPS receiver can use the determined position to access a local data base of available channels. Alternatively, the SPS receiver can use the determined position to access a local database of allocated channels in order to determine one or more available channels. The SPS receiver may display a prompt or message that indicates an FM channel over which output audio is modulated.

Abstract: A method calibrates a spread spectrum receiver having a received signal strength below a noise floor. The method includes estimating an input noise power, and measuring a noise power output from the receiver. The method also includes comparing the estimated input noise power with the measured output noise power to determine at least one calibration value. The method further includes calibrating the receiver based upon the at least one calibration value.

Abstract: The subject matter disclosed herein relates to a system and method for processing navigation signals received from multiple global navigation satellite systems (GNSS?). In a particular implementation, signals received from multiple GNSS? may be processed in a single receiver channel.

Abstract: A system and method are disclosed for generating a synthesized signal. A frequency synthesizer is used. The frequency synthesizer includes an input interface configured to receive an input signal having a reference frequency; a phase locked loop (PLL) coupled to the input interface, having a fractional N configuration and comprises a voltage controlled oscillator; wherein the voltage controlled oscillator is configured to generate the synthesized signal; and the voltage controlled oscillator includes an on-chip inductor.

Abstract: A system and method are disclosed for configuring a frequency synthesizer in a transceiver. Configuring a frequency synthesizer in a transceiver includes specifying a selection bit sequence wherein the selection bit sequence corresponds to a predetermined combination of transceiver characteristics; determining a plurality of synthesizer configuration parameters using the selection bit sequence; and configuring the frequency synthesizer using the plurality of synthesizer configuration parameters.

Abstract: A line interface couples a data transceiver to a transmission line via a transformer, the data transceiver transmitting signals in a first frequency range and receiving signals in a second frequency range. The line interface includes an input port for receiving an input signal voltage from an analog front end (AFE) chip, an output port, a line driver for amplifying the input signal voltage and supplying a transmit signal to the output port, a line port for sending the transmit signal and receiving a receive signal, termination resistors coupled between the output port and the line port, a receive signal port for supplying the receive signal to the AFE chip, a receive amplifier formed on the AFE chip coupled to the receive signal port, and a bridge network resistively coupling the line port and the output port to the receive signal port, the bridge network having a low-pass filter characteristic.

Abstract: A line driver couples a data transceiver to a transmission line having a load impedance Z via a transformer with a turns ratio of 1:n, the data transceiver transmitting signals in a first frequency range and receiving signals in a second frequency range different from the first frequency range. The line driver includes an input port for receiving an input signal voltage, an output port for supplying an output signal voltage to the transformer, and a differential amplifier having a low pass filter for amplifying the input signal voltage and outputting an amplified signal voltage. The line driver further includes termination resistors having a resistance Rt, where R t = Z 2 ? n 2 × k ( 0 < k ? 1 ) , and a positive feedback path for coupling the output signal voltage from the output port to an appropriate node of the differential amplifier so that a synthesized output impedance substantially matches the load impedance Z over the second frequency range.

Abstract: A line interface couples signals between a data transceiver and a transmission line having a load impedance Z. The line interface includes a transformer, a driver circuit for supplying a transmit signal from the data transceiver to the transformer, and a receiver circuit for receiving a receive signal from the transformer. The transformer includes a first port coupled to the transmission line, a second port coupled to the driver circuit, a third port coupled to the receiver circuit, a first winding part having a turns ratio of 1: n, where n>1, for coupling the transmit signal from the second port to the first port, and a second winding part having a turns ratio of 1: m, where m<n, for coupling the receive signal from the first port to the third port.

Abstract: A system and method are disclosed for generating a variable frequency output. A voltage controlled oscillator (VCO) is used. The VCO comprises a plurality of aggregate capacitor circuits, wherein each of the aggregate capacitor circuits has a collective capacitance, at least two of the collective capacitances have different values, and each of the aggregate capacitor circuits includes one or more individual capacitors wherein each of the individual capacitors are substantially the same size. The VCO further comprises a plurality of switches configured to select one or more aggregate capacitor circuits from among the plurality of aggregate capacitor circuits to form a discretely variable capacitor network having a discretely variable capacitance, wherein the discretely variable capacitor network is configured to cause an oscillator to generate a variable frequency as a result of the discretely variable capacitance.

Abstract: A system and method are disclosed for generating a synthesized signal. A frequency synthesizer is used. The frequency synthesizer includes an input interface configured to receive an input signal having a reference frequency; a phase locked loop (PLL) coupled to the input interface, having a fractional N configuration and comprises a voltage controlled oscillator; wherein the voltage controlled oscillator is configured to generate the synthesized signal; and the voltage controlled oscillator includes an on-chip inductor.

Abstract: A line driver for coupling a data transceiver to a transmission line having a load impedance via a transformer with a turns ratio of 1:n includes an input port for receiving an input signal voltage from the data transceiver, an output port for supplying an output signal voltage to the transformer, and an amplifier circuit for amplifying the input signal voltage. The amplifier circuit includes a first output stage, a second output stage coupled to the output port, an output resistor coupled to the first output stage, a feedback path from the first output stage to an input of the amplifier circuit, and a line matching network coupled between the first output stage and the second output stage, for compensating variations in the load impedance, so that a synthesized output impedance of the line driver substantially matches an actual load impedance Z of the transmission line.

Abstract: A dynamic supply control circuit is provided for a line driver. The line driver has an amplification factor G, receives an input signal voltage, and drives a transmission line having a load RL via a transformer having a turns ratio of 1:n. The circuit includes an input node for receiving an input signal voltage, a supply node for supplying a driving voltage to the line driver, a lift diode coupled between a fixed supply voltage and the supply node, a lift capacitor coupled between the supply node and an output node, and a lift amplifier having the amplification factor G coupled between the input node and the output node. The lift amplifier drives the lift capacitor when the input signal voltage is greater than an input threshold voltage, the input threshold voltage having a value greater than a common mode voltage of the input signal voltage.

Abstract: An ADSL central office transmission system for transmitting downstream DMT signals to a plurality of remote ADSL transceiver is disclosed. The system includes a DMT digital signal transceiver that generates a time division multiplexed digital signal that includes a plurality of DMT signals to be sent on a plurality of ADSL lines. A digital to analog converter converts the time division multiplexed digital signal into a time division multiplexed analog signal that includes a plurality of analog DMT signals. The analog to digital converter has an output that outputs the time division multiplexed analog signal. A switch selectively connects the output of the digital to analog converter to each of a plurality of transmitters. The transmitters are configured to drive the plurality of ADSL lines. Thus, the plurality ADSL lines are driven by the plurality of analog DMT signals.

Abstract: A digital-to-analog converter (“DAC”) and method for digital-to-analog conversion is disclosed. The DAC generally comprises a plurality of analog weights, a weight table adapted to store digital sizes of the plurality of analog weights, and a converter for searching for selected weights from the plurality of analog weights using the digital sizes stored in the weight table and for mapping a binary input to the selected analog weights. The digital sizes of all except for at least two of the analog weights are successively approximated using the assigned sizes of at least two of the analog weights. The method for digital-to-analog conversion, comprising receiving the binary input, searching for selected weights from analog weights using a weight table storing digital sizes of the analog weights, mapping the binary input to the selected weights, and outputting a sum of the selected analog weights.

Abstract: A reconstruction filter is described. An input is configured to receive an output signal from a digital to analog converter. An input sampling circuit is operative to store a sample of the output signal from the digital to analog converter. An input pulse generating switch that generates a pulse, the energy of the pulse being determined by the sample of the output signal from the digital to analog converter. An amplifier receives the pulse at an amplifier input and provides an output signal at an amplifier output so that an output signal is produced that reduces distortion caused by imperfections in digital to analog converter.