Abstract: A clock recovery circuit includes a clock detector configured to receive a serial data stream from a remote device over a reverse channel, wherein the serial data stream includes clock reference data, reverse channel data, or a combination of the clock reference data and the reverse channel data, and the clock detector configured to output a clock detect signal in response to detecting the clock reference data in the serial data stream; a phase lock loop including a first detector configured to receive the serial data stream and to detect phase and frequency; and a controller configured to receive the clock detect signal and to selectively enable the first detector based on the clock detect signal.

Abstract: A capacitive sensing system are configured to sense a capacitance value and convert the sensed capacitance value to a digital format. The capacitive sensing system provides good selectivity and immunity to noise and interference, which can be further enhanced by enabling spread spectrum excitation. In some embodiments, the capacitive sensing system utilizes a sinusoidal excitation signal that results in low electromagnetic emissions, limited to narrow frequency band. In some embodiments, the capacitive sensing system is configured to operate in a spread spectrum mode, in which the majority of the excitation signal power is carried in the assigned bandwidth. The excitation frequency and the bandwidth of the spread spectrum excitation signal are programmable in a wide range, which allows for avoiding frequency conflicts in the operating environment.

Abstract: A system includes a clock interconnect network having an input node and a plurality of output nodes. The clock interconnect network receives a clock input at the input node and distributes, based on the clock input, a plurality of clock signals via respective ones of the plurality of output nodes. A propagation delay of each of the plurality of clock signals distributed by the clock interconnect network is approximately equal to respective propagation delays of others of the plurality of clock signals distributed by the clock interconnect network. A digital-to-analog converter includes a plurality of segments, each outputting a respective output, and a plurality of drivers. Each of the plurality of drivers receives a respective one of the plurality of clock signals and provides a driver signal to a respective one of the plurality of segments based on the respective one of the plurality of clock signals.

Abstract: A system includes a clock interconnect network having an input node and a plurality of output nodes. The clock interconnect network receives a clock input at the input node and distributes, based on the clock input, a plurality of clock signals via respective ones of the plurality of output nodes. A propagation delay of each of the plurality of clock signals distributed by the clock interconnect network is approximately equal to respective propagation delays of others of the plurality of clock signals distributed by the clock interconnect network. A digital-to-analog converter includes a plurality of segments, each outputting a respective output, and a plurality of drivers. Each of the plurality of drivers receives a respective one of the plurality of clock signals and provides a driver signal to a respective one of the plurality of segments based on the respective one of the plurality of clock signals.

Abstract: A capacitive sensing system are configured to sense a capacitance value and convert the sensed capacitance value to a digital format. The capacitive sensing system provides good selectivity and immunity to noise and interference, which can be further enhanced by enabling spread spectrum excitation. In some embodiments, the capacitive sensing system utilizes a sinusoidal excitation signal that results in low electromagnetic emissions, limited to narrow frequency band. In some embodiments, the capacitive sensing system is configured to operate in a spread spectrum mode, in which the majority of the excitation signal power is carried in the assigned bandwidth. The excitation frequency and the bandwidth of the spread spectrum excitation signal are programmable in a wide range, which allows for avoiding frequency conflicts in the operating environment.

Abstract: A digital-to-analog converter (DAC) system includes a DAC and a clock interconnect module. The DAC includes a plurality of segments and a plurality of drivers. Each of the plurality of segments receives driver signals from a respective one of the plurality of drivers and generates a positive output and a negative output based on the driver signals. Each of the plurality of drivers receives a respective one of a plurality of clock signals and outputs the driver signals based on the respective one of the plurality of clock signals. The clock interconnect module includes an interconnect loop. A clock input is connected to a first portion of the interconnect loop and the plurality of clock signals are output from a second portion of the interconnect loop connected to the plurality of drivers. An output interconnect module receives the positive outputs and the negative outputs generates a differential output signal.

Abstract: A capacitive sensing system are configured to sense a capacitance value and convert the sensed capacitance value to a digital format. The capacitive sensing system provides good selectivity and immunity to noise and interference, which can be further enhanced by enabling spread spectrum excitation. In some embodiments, the capacitive sensing system utilizes a sinusoidal excitation signal that results in low electromagnetic emissions, limited to narrow frequency band. In some embodiments, the capacitive sensing system is configured to operate in a spread spectrum mode, in which the majority of the excitation signal power is carried in the assigned bandwidth. The excitation frequency and the bandwidth of the spread spectrum excitation signal are programmable in a wide range, which allows for avoiding frequency conflicts in the operating environment.

Abstract: A digital-to-analog converter (DAC) system includes a DAC and a clock interconnect module. The DAC includes a plurality of segments and a plurality of drivers. Each of the plurality of segments receives driver signals from a respective one of the plurality of drivers and generates a positive output and a negative output based on the driver signals. Each of the plurality of drivers receives a respective one of a plurality of clock signals and outputs the driver signals based on the respective one of the plurality of clock signals. The clock interconnect module includes an interconnect loop. A clock input is connected to a first portion of the interconnect loop and the plurality of clock signals are output from a second portion of the interconnect loop connected to the plurality of drivers. An output interconnect module receives the positive outputs and the negative outputs generates a differential output signal.

Abstract: A capacitive sensing system are configured to sense a capacitance value and convert the sensed capacitance value to a digital format. The capacitive sensing system provides good selectivity and immunity to noise and interference, which can be further enhanced by enabling spread spectrum excitation. In some embodiments, the capacitive sensing system utilizes a sinusoidal excitation signal that results in low electromagnetic emissions, limited to narrow frequency band. In some embodiments, the capacitive sensing system is configured to operate in a spread spectrum mode, in which the majority of the excitation signal power is carried in the assigned bandwidth. The excitation frequency and the bandwidth of the spread spectrum excitation signal are programmable in a wide range, which allows for avoiding frequency conflicts in the operating environment.

Abstract: A capacitive sensing system are configured to sense a capacitance value and convert the sensed capacitance value to a digital format. The capacitive sensing system provides good selectivity and immunity to noise and interference, which can be further enhanced by enabling spread spectrum excitation. In some embodiments, the capacitive sensing system utilizes a sinusoidal excitation signal that results in low electromagnetic emissions, limited to narrow frequency band. In some embodiments, the capacitive sensing system is configured to operate in a spread spectrum mode, in which the majority of the excitation signal power is carried in the assigned bandwidth. The excitation frequency and the bandwidth of the spread spectrum excitation signal are programmable in a wide range, which allows for avoiding frequency conflicts in the operating environment.

Abstract: A capacitive sensing system are configured to sense a capacitance value and convert the sensed capacitance value to a digital format. The capacitive sensing system provides good selectivity and immunity to noise and interference, which can be further enhanced by enabling spread spectrum excitation. In some embodiments, the capacitive sensing system utilizes a sinusoidal excitation signal that results in low electromagnetic emissions, limited to narrow frequency band. In some embodiments, the capacitive sensing system is configured to operate in a spread spectrum mode, in which the majority of the excitation signal power is carried in the assigned bandwidth. The excitation frequency and the bandwidth of the spread spectrum excitation signal are programmable in a wide range, which allows for avoiding frequency conflicts in the operating environment.

Abstract: A current steering digital-to-analog (DAC) having improved dynamic performance and output signal quality (i.e. improved SFDR characteristic). The DAC includes current steering segments each having differential transistors to steer a current from a summing node to either the positive or negative output. The DAC further comprises a control circuit to reduce the variation of the voltage present at each summing node. More specifically, the control circuit includes a first circuit that controls the threshold voltage of the corresponding differential transistors that are electrically connected to the positive output in response to the sensed positive output voltage such that the voltages at the corresponding summing nodes remain constant.

Abstract: A high Q tank circuit is employed at the output of a digital, crystal controlled oscillator to generate a high voltage amplitude signal. The tank circuit has a resonant frequency greater than the maximum required oscillation frequency. During each oscillation cycle, oscillation within the tank circuit is stopped in an energy efficient manner such that the resonant oscillation period is extended to match the required oscillation period. Modulation of the digital oscillator signal appears in the output circuit signal.

Abstract: A high Q tank circuit is employed at the output of a digital, crystal controlled oscillator to generate a high voltage amplitude signal. The tank circuit has a resonant frequency greater than the maximum required oscillation frequency. During each oscillation cycle, oscillation within the tank circuit is stopped in an energy efficient manner such that the resonant oscillation period is extended to match the required oscillation period. Modulation of the digital oscillator signal appears in the output circuit signal.

Abstract: A flat panel display is coupled with an electrostatic stylus driven digitizing panel to produce a display and digitizer system having an interference control feature. The interference control feature first determines the operating frequency of the flat panel display and/or the operating frequency of the stylus. The interference controller may then incrementally reduce the operating frequency of the flat panel display and/or the operating frequency of the stylus until the operating frequency causing the least interference is ascertained. Once the operating frequency causing the least interference is ascertained the interference controller selects new operating parameters for the display and digitizer system.

Abstract: An electrostatic digitizing panel capable of filtering offset loads such that stylus or fingertip position information is more accurately obtained. The present invention utilizes a new method of calculating the stylus position such that the digitizer surface is sensitive only to the electric field concentrated in the area occupied by the stylus or fingertip. Thus, the panel has a substantially reduced sensitivity to fields emitted from a user's hand or noise fields emitted from the surface of a display, or the like, coupled to the panel.

Abstract: A method and apparatus for detecting when a second object touches a digitizing panel while a first object is touching the digitizing panel is disclosed.

Abstract: A method and apparatus for generating an output signal in a digitizer. The method includes the steps of generating a first signal when a user contacts a sensor panel wherein the first signal has a first component and a second component, generating a second signal which is substantially identical to the first component of the first signal, and using the second signal to cancel out the first component of the first signal so as to generate the output signal which is substantially identical to the second component of the first signal.

Abstract: A digitizing panel responsive to a signal transmitted from a stylus for generating stylus position information is disclosed. The digitizing panel includes a coordinate generator for determining coordinate data indicative of a position of the stylus relative to the digitizing panel, a velocity calculator for determining a stylus velocity value based on the coordinate data, a mechanism for determining a filter bandwidth value based on the stylus velocity value, a filter for filtering the coordinate data wherein the filter has a predetermined bandwidth characteristic, and a mechanism for varying the predetermined bandwidth characteristic based on the filter bandwidth value. A method for filtering position data of a stylus associated with a digitizing panel is also disclosed.

Abstract: A method and apparatus for aligning a first coordinate system of a digitizing panel with a second coordinate system of a display device. The method includes the steps of displaying a plurality of reference points on the display device, each of the reference points having a X.sub.ref, Y.sub.ref coordinate value, determining a plurality of first Xr, Yr coordinate values from the digitizing panel which are indicative of a plurality of positions of an object positioned relative to the plurality of reference points, determining a plurality of channel gain correction values from the plurality of first Xr, Yr coordinate, values and the plurality of X.sub.ref, Y.sub.ref coordinate values, and storing the plurality of channel gain correction values for use in correcting a second Xr, Yr coordinate value which is indicative of a position of an object relative to the digitizing panel.