Abstract: A signal analysis system includes a memory that stores instructions; and a processor that executes the instructions.

Abstract: A signal analysis system includes a memory and a processor. The memory stores instructions; and the processor executes the instructions. When executed by the processor, the instructions cause the signal analysis system to: filter an orthogonal frequency-division multiplexed signal with a first filtering bandwidth larger than a modulation bandwidth of the orthogonal frequency-division multiplexed signal to produce a filtered analog signal; digitize the filtered analog signal to obtain a digitization of the filtered analog signal; obtain a single measurement of a modulated waveform from the digitization; upsample the single measurement at a multiple of five (5) times or higher of a Nyquist sampling rate; and compute a complementary cumulative distribution function (CCDF) of the modulated waveform of the orthogonal frequency-division multiplexed signal based on upsampling the single measurement.

Abstract: A system and method are provided for measuring residual phase noise of a measurement signal using a phase detector including a mixer. The method includes injecting a phase noise spur in a stimulus signal having a known magnitude at a known offset frequency from the stimulus signal carrier frequency; inputting the stimulus signal to a DUT to output a measurement signal; inputting the measurement signal to RF input of the mixer via RF path; inputting the stimulus signal to LO input of the mixer via LO path; mixing the measurement and stimulus signals to provide a residual phase noise signal; measuring actual rejection of stimulus phase noise at the know offset frequency; determining a relative delay between the measurement and stimulus signals in the RF and LO paths based on the actual rejection; and minimizing relative delay between the measurement and stimulus signals to reduce residual phase noise measurement floor.

Abstract: An apparatus and method: access repeated copies of an OFDM output signal produced by a device in response to corresponding repeated copies of an OFDM input signal; for each copy of the OFDM output signal, time align the OFDM output symbols to the OFDM input symbols, and de-rotate a phase of the OFDM output signal with respect to the OFDM input signal; coherently sum and average the copies of the OFDM output signal; determine a variance of each copy of the OFDM output signal, and an ensemble variance of all of the copies of the OFDM output signal; discard copies of the OFDM output signal whose variance differs from the ensemble variance by more than a threshold amount to produce a qualified set of copies; determine a mean value of the qualified set of copies; and determine a total noise power of the qualified set of copies from the mean value.

Abstract: an orthogonal frequency division multiplexed (OFDM) output signal produced by a device in response to an OFDM input signal is accessed. The OFDM input signal includes OFDM input symbols in the time domain and the OFDM output signal includes OFDM output symbols in the time domain. The OFDM output symbols are time-aligned to the OFDM input symbols and a phase of the OFDM output signal is de-rotated with respect to the OFDM input signal. A complex equalization filter is applied to the OFDM output symbols in the time domain to obtain an estimate of the OFDM input symbols A distortion signal of the OFDM output signal is determined by subtracting the estimate of the OFDM input symbols. An error vector magnitude (EVM) is determined by dividing a root mean square of the distortion, by a root mean square of the OFDM input signal.

Abstract: An apparatus and method: access repeated copies of an OFDM output signal produced by a device in response to corresponding repeated copies of an OFDM input signal; for each copy of the OFDM output signal, time align the OFDM output symbols to the OFDM input symbols, and de-rotate a phase of the OFDM output signal with respect to the OFDM input signal; coherently sum and average the copies of the OFDM output signal; determine a variance of each copy of the OFDM output signal, and an ensemble variance of all of the copies of the OFDM output signal; discard copies of the OFDM output signal whose variance differs from the ensemble variance by more than a threshold amount to produce a qualified set of copies; determine a mean value of the qualified set of copies; and determine a total noise power of the qualified set of copies from the mean value.

Abstract: A system and method are provided for measuring absolute phase noise of a test signal from a DUT using a reference source for generating an RF reference signal, a mixer for mixing the RF reference signal and an input signal, an adjustable DC voltage source for outputting a DC voltage, and a PLL for maintaining a 90 degree quadrature between the RF reference and input signals. The method includes mixing RF calibration signals and the RF reference signal to provide calibration phase signals, at least one of the RF calibration signals having one-tone AM modulation; monitoring modulation tone frequency of the one-tone AM modulation; adjusting the DC voltage output by the adjustable DC voltage source to minimize a voltage level of the tone frequency being monitored; mixing the test signal and the RF reference signal to provide a measurement phase signal for measuring absolute phase noise of the test signal.

Abstract: A touch panel system is described that is configured to reduce inter-symbol interference (ISI). In an implementation, the touch panel system includes a touch panel assembly that includes a plurality of drive electrodes arranged one next to another and a plurality of sensor electrodes arranged one next to another across the drive electrodes to form a plurality of pixels having a mutual capacitance. The touch panel system also includes a transmitter configured to drive the drive electrodes with drive signals derived at least partially from excitation values. The transmitter is configured to apply a window function to the drive signals. The system also includes a receiver configured to sense signals furnished from the sensor electrodes and to determine the mutual capacitance of the pixels.

Abstract: A touch panel controller may include a communications module configured to receive pixel values, where each pixel value represents a capacitance associated with a pixel formed at a drive electrode and a sensor electrode of a touch panel. The touch panel controller may also include a processing module configured to discard pixel values below a noise threshold, discard pixel values for non-zero pixels that are not adjacent to non-zero pixels, reject detected input for pixel values associated with a palm input, compute an initial centroid associated with the pixel values, reject detected input for pixel values associated with a hover input, and provide detected input that is not associated with palm input or hover input.

Abstract: A method for watering plants using a self-contained high pressure distribution system with a water reservoir. A mini gear pump is used for pumping water to pressure compensated drip emitters at individual plants. A method for monitoring soil moisture content and programming of individual watering of plants through an energy efficient wireless networking system. The high-pressure water in the plant watering system is used as a communication physical channel for the wireless networking for improving wireless communication range and battery life of wireless terminals. Chip-level Differential Encoding based Spread Spectrum signaling is used for reducing wireless networking solution cost, improving wireless link budget, improving immunity to interference, and increasing battery life of wireless terminals.

Abstract: A capacitive touch panel includes elongated drive electrodes arranged next to one another and elongated sensor electrodes arranged next to one another across the drive electrodes. Together, the drive electrodes and the sensor electrodes define a coordinate system where each coordinate location comprises a capacitor formed at an intersection between one of the drive electrodes and one of the sensor electrodes. In implementations, the drive electrodes and/or the sensor electrodes are configured to block capacitance between a touch at a coordinate location and the drive electrodes during a floating condition for the panel. In other implementations, the drive electrodes and/or the sensor electrodes are configured to exaggerate capacitance between a touch at a coordinate location and the drive electrodes during a floating condition for the panel.

Abstract: An audio signal analysis method is provided for detecting the opening and closing of a medicine bottle cap in a robust manner using a micro speaker and a microphone along with associated mixed signal electronics. It is also used for robust tamper detection and for monitoring liquid medication consumption accurately. In a preferred embodiment an un-modulated OFDM signal is used that covers the entire operating audio spectrum. In another embodiment, Complimentary code based phase encoding of the subcarrier phases is used to reduce the peak to average power of the OFDM signal, thereby enabling higher transmit power of the audio signal to mitigate against interference. A suitable wireless device can be co-located with the mixed signal electronics for sending the bottle usage, medication reminder alarm, and tamper status to the medication compliance monitoring system or to the user's cell phone.

Abstract: One embodiment of the present invention provides an apparatus for allowing a Wi-Fi module to operate over TV white space (TVWS) bands. The apparatus includes a first receiver coupled to a Wi-Fi module and configured to receive a Wi-Fi signal from the Wi-Fi module, an analog-to-digital conversion (ADC) module coupled to the first receiver and configured to convert the received Wi-Fi signal to the digital domain, a spectral-shaping module configured to reshape a spectrum of the converted digital Wi-Fi signal, a digital-to-analog conversion (DAC) module coupled to the spectral-shaping module, and a first transmitter coupled to the DAC module and configured to transmit signals in TV white space (TVWS) bands.

Abstract: A touch panel controller may include a communications module configured to receive pixel values, where each pixel value represents a capacitance associated with a pixel formed at a drive electrode and a sensor electrode of a touch panel. The touch panel controller may also include a processing module configured to discard pixel values below a noise threshold, discard pixel values for non-zero pixels that are not adjacent to non-zero pixels, reject detected input for pixel values associated with a palm input, compute an initial centroid associated with the pixel values, reject detected input for pixel values associated with a hover input, and provide detected input that is not associated with palm input or hover input.

Abstract: A touch panel system is described that is configured to reduce inter-symbol interference (ISI). In an implementation, the touch panel system includes a touch panel assembly that includes a plurality of drive electrodes arranged one next to another and a plurality of sensor electrodes arranged one next to another across the drive electrodes to form a plurality of pixels having a mutual capacitance. The touch panel system also includes a transmitter configured to drive the drive electrodes with drive signals derived at least partially from excitation values. The transmitter is configured to apply a window function to the drive signals. The system also includes a receiver configured to sense signals furnished from the sensor electrodes and to determine the mutual capacitance of the pixels.

Abstract: Stylus tip configurations may reduce shadow effect of the stylus tip on capacitance measurements by reducing capacitive coupling between undesired portions of the stylus tip and the capacitive sensing surface. Additionally signal-to-noise ratio (SNR) of a stylus on a plurality of capacitance sensing electrodes may be improved by reducing the self capacitance between the stylus tip and the receive electrodes of a mutual capacitance touch screen.

Abstract: A method of mitigating a phase shift in a mutual capacitance touch screen panel having a plurality of row conductors intersecting with a plurality of column conductors to form a matrix of pixels, the method comprising: driving the row conductors with row drive signals formed from an excitation matrix, wherein each row in the excitation matrix is orthogonal to every other row in the excitation matrix, and the excitation matrix has a dimension larger than the matrix of pixels; sensing signals from the column conductors; and determining the mutual capacitance of the pixels using the sensed signals and an inverse of the excitation matrix. The excitation matrix can be a Hadamard matrix or a modified Hadamard matrix and can comprise a cyclic extension at the end of each row. A different region-specific phase shift can be applied to different clusters of signals.

Abstract: A capacitive touch panel includes elongated drive electrodes arranged next to one another and having a characteristic spacing between adjacent drive electrodes. The capacitive touch panel also includes elongated sensor electrodes arranged next to one another across the drive electrodes and having a characteristic spacing between adjacent sensor electrodes. The drive electrodes and/or the sensor electrodes have protrusions into the spaces between adjacent electrodes. The characteristic spacing between the sensor electrodes may be at least substantially greater than the characteristic spacing between the drive electrodes. The sensor electrodes may have a pitch based upon a touch diameter of a finger, and the touch panel may be capable of sensing a stylus having a touch diameter substantially less than the touch diameter of the finger.

Abstract: A touch panel controller may include a communications module configured to receive pixel values, where each pixel value represents a capacitance associated with a pixel formed at a drive electrode and a sensor electrode of a touch panel. The touch panel controller may also include a processing module configured to discard pixel values below a noise threshold, discard pixel values for non-zero pixels that are not adjacent to non-zero pixels, reject detected input for pixel values associated with a palm input, compute an initial centroid associated with the pixel values, reject detected input for pixel values associated with a hover input, and provide detected input that is not associated with palm input or hover input.

Abstract: Stylus tip configurations may reduce shadow effect of the stylus tip on capacitance measurements by reducing capacitive coupling between undesired portions of the stylus tip and the capacitive sensing surface. Additionally signal-to-noise ratio (SNR) of a stylus on a plurality of capacitance sensing electrodes may be improved by reducing the self capacitance between the stylus tip and the receive electrodes of a mutual capacitance touch screen.