Abstract: A touch-sensitive device includes a touch panel, drive unit, and measurement unit. A touch applied to a given node of the panel changes a mutual capacitive coupling between a given drive and sense electrode of the touch panel, or changes a self-capacitive coupling the between a given electrode and ground. The drive unit delivers to the drive electrodes of the touch panel or to the self-capacitance measurement amplifiers of all electrodes, subcarriers of a composites carrier modulated OFDM signal by using SSB or DSB modulation based up-conversion, and these subcarriers are complementary code sequence-based phase encoded for PAPR reduction of the OFDM signal. The measurement unit receives signals from the receive electrodes, or directly from local receiver amplifiers at each electrode, and analyzes the signal using FFT or maximum likelihood estimation to determine the mutual coupling capacitance between each of the drive and receive electrodes or the self-capacitance of each electrode.

Abstract: Systems for and methods of decoding the coordinates a touch upon a touch panel. The touch panel comprises drive channels and sense channels. A Hadamard excitation matrix and a cover code are used to generate drive signals to the drive channels of the touch panel. Sense channels of the touch panel are demodulated and decoded using an inverse excitation matrix. The inverse of an Hadamard excitation matrix is the same as the Hadamard excitation matrix. A Hadamard excitation matrix is orthogonal and enables the use of cyclic extension of excitation of the drive signals to reduce the effect of phase shift of drive signals propagated to the sense channels. The cover code enables reduction of the dynamic range of amplifiers at the sense channels.

Abstract: A touch screen controller for a capacitive touch screen panel having row conductors intersecting column conductors to form pixels, the touch screen controller comprising: a transmitting unit configured to drive the row conductors with signals formed from an excitation matrix, and a receiving unit configured to sense signals from the column conductors and to determine the capacitance of the pixels using the sensed signals. In some embodiments, the receiving unit is configured to apply zero-ISI filtering to the sensed signals prior to the capacitance of the pixels being determined. In some embodiments, the transmitting unit is configured to spread each bit of the row drive signals with a pseudo-noise code, and the receiving unit is configured to de-spread the sensed signals with the pseudo-noise code. In some embodiments, the transmitting unit is configured to pulse shape the row drive signals.

Abstract: A projected capacitive touch panel that can detect touch pressure. The cover layer of projected capacitive touch panel has protrusions with gaps that fill up partially when finger is pressed, thereby registering a large change in projected capacitance. A keyboard using such device with optional mechanical switches underneath the touch surface for tactile feedback. Haptic feedback is coupled to detection of touch pressure. Reconfigurable keyboard and trackpad regions on a touch panel sensitive to touch pressure with tactile feedback from underlying mechanical switches. A mouse with left and right click support using projected capacitive touchpad with pressure detection for mouse click. Human finger based mimicking of mouse operation in combination with touch pressure detection. Supporting gestures that use touch pressure. Providing a visual feedback in an underlying display when touch pressure is detected. Providing an audio feedback when touch pressure is detected.

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: A touch-sensitive device includes a touch panel, drive unit, and measurement unit. A touch applied to a given node of the panel changes a mutual capacitive coupling between a given drive and sense electrode of the touch panel, or changes a self-capacitive coupling the between a given electrode and ground. The drive unit delivers to the drive electrodes of the touch panel or to the self-capacitance measurement amplifiers of all electrodes, subcarriers of a composites carrier modulated OFDM signal by using SSB or DSB modulation based up-conversion, and these subcarriers are complementary code sequence-based phase encoded for PAPR reduction of the OFDM signal. The measurement unit receives signals from the receive electrodes, or directly from local receiver amplifiers at each electrode, and analyzes the signal using FFT or maximum likelihood estimation to determine the mutual coupling capacitance between each of the drive and receive electrodes or the self-capacitance of each electrode.

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: 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 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: Methods to relax the second order intercept point of transceivers for multi-carrier and OFDM (such as IEEE 802.11a/g and 802.16) based zero IF wireless receivers that need to work in an environment with strong jamming signals, such as, for example, WLAN modules in Smart Phones. Due to the poor IP2 of WLAN (wireless local area network) receivers, unacceptable DC signals are produced in the I,Q quadrature paths when a strong out-of-band signal is received, e.g., from a co-located GSM phone. This completely destroys the received WLAN packet, resulting in an unacceptably high PER (packet error rate). In one aspect, the mixer reference for the receiver is effectively shifted (corrected) to accurately match the carrier of the received signal. In another aspect, the carrier is uncorrected for transmission. In still another aspect, a continuous DC correction is made on a per symbol basis. In still another aspect, the DC correction and the frequency correction are used together. Various embodiments are disclosed.

Abstract: A method for reducing frequency glitches in a digital transceiver due to power amplifier input impedance variations. According to the method, the power amplifier is switched on after the end of a prior packet reception period and before a new packet transmission begins. Instead of ramping the power amplifier gain, the method ramps the modulation signals. As a consequence, any VCO frequency transients that may result from turning on the power amplifier have an opportunity to decay before the new packet transmission is initiated. This technique effectively isolates the transmitter power amplifier from the frequency synthesizer VCO to facilitate fast switching transceiver operation.

Abstract: This invention describes how to quickly cancel DC offsets that are present in the two quadrature paths of a zero intermediate frequency transceiver. Previously known techniques are not suitable for the 5 GHz WLAN standards because of the very short transmit to receive turn around times and extraordinarily large DC offsets in these systems. This invention solves the above problems. The present invention uses both AC and DC coupling along with automatic gain control techniques to remove unwanted DC offsets within an acceptable time period. The invention further uses a digital signal processor to estimate and subtract out the DC offset errors using time averaged signals. The digital signal processing circuit is capable of further AC filtering and Analog to Digital conversions.

Abstract: Improved DC cancellation in zero-IF receivers for eliminating the DC offset that otherwise would be caused by the AC voltage on a coupling capacitor at the time of switching from AC coupling to DC coupling. The coupling capacitor normally is connected first as a high pass filter to block any DC component, and then directly coupled as a direct or DC coupler. However any AC component of voltage on the coupling capacitor at the moment of switching normally remains as a DC offset. In accordance with the invention, the component of AC voltage on a coupling capacitor is tracked, and when switched to DC coupling, the component of AC voltage on the capacitor at the time of switching is held and subtracted from the signal path, thereby canceling the DC offset component that otherwise would be caused. Alternate embodiments are disclosed, including embodiments for accelerating capacitance charging for speed-up of the method.

Abstract: In a transceiver comprising a time-division-duplex (TDD) of transmit and receive functions, the characteristics of unwanted image signal energy being transmitted from the transceiver are determined, and thereafter feedback is provided to the transmitter to reduce this unwanted image signal energy. The image signal energy is measured by the receiver component of the transceiver and fed back to the transmitter component of the transceiver. The transmitter component uses the fed back information to adjust the gain and or phase relationship between the quadrature signals that are subsequently quadrature-phase modulated and transmitted. A variety of techniques can be employed to allow the image signal energy to be measured directly by the receiver component. The phase modulation signals at the transmitter can be interchanged, so that the unwanted image signal energy is transmitted in the sideband of the intended signal.

Abstract: A method for reducing frequency glitches in a digital transceiver due to power amplifier input impedance variations. According to the method, the power amplifier is switched on after the end of a prior packet reception period and before a new packet transmission begins. Instead of ramping the power amplifier gain, the method ramps the modulation signals. As a consequence, any VCO frequency transients that may result from turning on the power amplifier have an opportunity to decay before the new packet transmission is initiated. This technique effectively isolates the transmitter power amplifier from the frequency synthesizer VCO to facilitate fast switching transceiver operation.

Abstract: Improved DC cancellation in zero-IF receivers for eliminating the DC offset that otherwise would be caused by the AC voltage on a coupling capacitor at the time of switching from AC coupling to DC coupling. The coupling capacitor normally is connected first as a high pass filter to block any DC component, and then directly coupled as a direct or DC coupler. However any AC component of voltage on the coupling capacitor at the moment of switching normally remains as a DC offset. In accordance with the invention, the component of AC voltage on a coupling capacitor is tracked, and when switched to DC coupling, the component of AC voltage on the capacitor at the time of switching is held and subtracted from the signal path, thereby canceling the DC offset component that otherwise would be caused. Alternate embodiments are disclosed, including embodiments for accelerating capacitance charging for speed-up of the method.

Abstract: This invention describes how to quickly cancel DC offsets that are present in the two quadrature paths of a zero intermediate frequency transceiver. Previously known techniques are not suitable for the 5 GHz WLAN standards because of the very short transmit to receive turn around times and extraordinarily large DC offsets in these systems. This invention solves the above problems. The present invention uses both AC and DC coupling along with automatic gain control techniques to remove unwanted DC offsets within an acceptable time period. The invention further uses a digital signal processor to estimate and subtract out the DC offset errors using time averaged signals. The digital signal processing circuit is capable of further AC filtering and Analog to Digital conversions.

Abstract: A method for reducing frequency glitches in a digital transceiver due to power amplifier input impedance variations. According to the method, the power amplifier is switched on after the end of a prior packet reception period and before a new packet transmission begins. Instead of ramping the power amplifier gain, the method ramps the modulation signals. As a consequence, any VCO frequency transients that may result from turning on the power amplifier have an opportunity to decay before the new packet transmission is initiated. This technique effectively isolates the transmitter power amplifier from the frequency synthesizer VCO to facilitate fast switching transceiver operation.

Abstract: This invention describes how to quickly cancel DC offsets that are present in the two quadrature paths of a zero intermediate frequency transceiver. Previously known techniques are not suitable for the 5 GHz WLAN standards because of the very short transmit to receive turn around times and extraordinarily large dc offsets in these systems. This invention solves the above problems. The present invention uses both AC and DC coupling along with automatic gain control techniques to remove unwanted DC offsets within an acceptable time period. The invention further uses a digital signal processor to estimate and subtract out the DC offset errors using time averaged signals. The digital signal processing circuit is capable of further AC filtering and Analog to Digital conversions.

Abstract: The present invention utilizes circuitry, already present in receivers, to calibrate and correct for gain and phase errors in a transceiver device. The present invention employs a digital signal processor along with multiple phase shifters and all pass networks to ensure proper levels of quadrature signals within the transceiver. An internally generated double sideband suppressed carrier signal is created to produce the calibration signals used by the digital signal processor.