Abstract: A method includes receiving (S1), from a touch panel (1), force values (23) corresponding to a plurality of piezoelectric sensors (5,6, 7). Each piezoelectric sensor corresponds to a physical location (xm, yn) on the touch panel. The method also includes receiving (S2) an identification of which, if any, of the force values (23) are influenced by coupling to external electric fields. The method also includes, in response to one or more force values (23) being identified as influenced by coupling to external electric fields (S3), setting the corresponding force values (23) as excluded force values (S5), and setting the remaining force values (23) as valid force values (S5). The method also includes interpolating and/or extrapolating (S6), based on the valid force values, one or more reconstructed force values (25) corresponding to same physical locations (xm, yn) as the respective excluded force values (23).

Abstract: Apparatus (22) for processing signals from a touch panel (10) is described. The touch panel (10) includes a layer of piezoelectric material (16) disposed between a plurality of sensing electrodes (14, 20) and at least one common electrode (15). The apparatus (22) includes a first circuit (23) for connection to the plurality of sensing electrodes (14, 20). The first circuit (23) is configured to generate a plurality of first pressure signals (29). Each first pressure signal (29) corresponds to one or more sensing electrodes (14, 20) and is indicative of a pressure acting on the touch panel (10) proximate to the corresponding one or more sensing electrodes (14, 20). The apparatus (22) also includes a second circuit (24) for connection to the at least one common electrode (15). The second circuit (24) is configured to generate a second pressure signal (30) indicative of a total pressure applied to the touch panel (10).

Abstract: A device (116) for processing signals from a projected capacitance touch panel (43) is described. The projected capacitance touch panel (43) includes a layer of piezoelectric material (9) disposed between a number of sensing electrodes (7, 27) and at least one counter electrode (8). The device (116) includes a capacitive touch controller (84) having a number of measurement ports (122). The device (116) also includes a number of charge amplifiers (123). The device (116) also includes a number of terminals (C1, . . . , C5, D1, . . . , D5) for connection to the sensing electrodes (7, 27) of the projected capacitance touch panel (43). Each terminal (C1, . . . , C5, D1, . . . , D5) is connected to one of the measurement ports (122). Each terminal (C1, . . . , C5, D1, . . . , D5) is also connected to an input of one of the charge amplifiers (123) via a corresponding switch (SW) of a number of switches (117a, 117b).

Abstract: A method of processing signals from a touch panel for combined capacitive and force sensing includes receiving, from the touch panel, pressure signals from a plurality of piezoelectric sensors and capacitance signals from a plurality of capacitive touch sensors. The method also includes determining, based on the capacitance signals, a user interaction period during which a user interaction with the touch panel occurs. The method also includes generating processed pressure signals based on the received pressure signals. The method also includes measuring a force applied to each of the plurality of piezoelectric sensors by the user interaction during the user interaction period by conditionally integrating the corresponding processed pressure signals according to a state register corresponding to the user interaction. The state register takes one of two or more values. Each user interaction is initialised in a first state value.

Abstract: A device (42) is provided for processing signals (10) from a projected capacitance touch panel (43), the touch panel (43) including a layer of piezoelectric material (9) disposed between a plurality of first electrodes (7, 27) and at least one second electrode (8). The device is configured, in response to receiving input signals (10) from a given first electrode (7, 27), to generate a pressure signal (15a, 15b) indicative of a pressure applied to the touch panel (43) proximate to the given first electrode (7, 27) and a capacitance signal (54a, 54b) indicative of a capacitance of the given first electrode (7, 27). The device (42) includes an amplifier (52) configured to generate an amplified signal (14a, 14b) based on the input signals (10).

Abstract: A touchscreen system for generating localised haptic excitations includes a touchscreen panel for measuring force and/or capacitance. The touchscreen system includes one or more first piezoelectric transducers arranged to generate excitations in the touchscreen panel along a first line. The touchscreen system includes one or more second piezoelectric transducers arranged to generate excitations in the touchscreen panel along a second line which is inclined to the first line at an angle. The touchscreen system includes a pressure and/or capacitance sensing module connected to the touchscreen panel and configured to measure a force and/or capacitance from the touchscreen panel.

Abstract: A continuous time sigma delta converter has a filter and converter components having known non-ideal characteristics. A compensation circuit has error modelling components arranged to model the non-ideal characteristics of the converter. A summation block combines a compensation signal from the compensation circuit with a non-ideal output signal from the converter in order to provide a compensated output signal. This has substantially no effect on other modulator performance characteristics and contributes to the implementation of giga sample-per-second Continuous Time sigma deltas having the dynamic range capabilities of traditional DT sigma deltas.

Abstract: A continuous time sigma delta converter has a filter and converter components having known non-ideal characteristics. A compensation circuit has error modelling components arranged to model the non-ideal characteristics of the converter. A summation block combines a compensation signal from the compensation circuit with a non-ideal output signal from the converter in order to provide a compensated output signal. This has substantially no effect on other modulator performance characteristics and contributes to the implementation of giga sample-per-second Continuous Time sigma deltas having the dynamic range capabilities of traditional DT sigma deltas.

Abstract: An apparatus and method for an improved chopping mixer (100) having a bipolar mixer stage (140) for mixing signals (lp, In, LOp, LOn) received thereby; an output chopping stage (160); and an AC coupling stage (150) for coupling the mixed signal to the output chopping stage. The signal prior to the chopping output stage is centered at the chopping clock frequency rather than DC. AC coupling allows removal of common mode signal in a desired frequency range. Also, the second order component present on each single ended output will also be DC blocked by the AC coupling capacitors, resulting in improved second order IP2 performance.

Abstract: An apparatus and method for an improved chopping mixer (100) having a bipolar mixer stage (140) for mixing signals (Ip, In, LOp, LOn) received thereby; an output chopping stage (160); and an AC coupling stage (150) for coupling the mixed signal to the output chopping stage. The signal prior to the chopping output stage is centered at the chopping clock frequency rather than DC. AC coupling allows removal of common mode signal in a desired frequency range. Also, the second order component present on each single ended output will also be DC blocked by the AC coupling capacitors, resulting in improved second order IP2 performance.

Abstract: A dynamic range on demand radio frequency (RF) receiver (300) includes a wideband detector (303), off-channel detector (313) and on-channel detector (327) supplying input to an automatic gain control (307) for adjusting a dynamic control stage to control dynamic range and resolution of digital baseband signals (329, 331).

Abstract: A dynamic range on demand radio frequency (RF) receiver (300) includes a wideband detector (303), off-channel detector (313) and on-channel detector (327) supplying input to an automatic gain control (307) for adjusting a dynamic control stage to control dynamic range and resolution of digital baseband signals (329, 331).

Abstract: Communication apparatus (100) corrects for amplitude imbalance caused by differences in circuitry that process in-phase and quadrature signals. The in-phase and quadrature signals are alternately routed in rapid succession through first and second parallel processing circuits or signal paths (140, 150) to cancel imbalances between the signal paths. Switches (132, 134) are employed at inputs to and outputs from corresponding portions of both signal paths, and these switches (132, 134) are synchronously operated in response to a control signal to interchange signals on the signal paths.

Abstract: A system is provided which facilitates a single-channel signal processing system. The system includes a single mixing stage, wherein an RF input signal is mixed with an In-Phase and a Quadrature-Phase signal. The mixing stage generates a multiplexed output signal for subsequent signal processing.

Abstract: A direct current (DC) offset correction loop (200) for determining the required amount of DC offset to an analog input signal includes a digital integrator (211) for measuring the amount of DC offset present at the final output of a forward signal path and a hold circuit (213) for controlling the digital integrator (213). The DC offset correction loop (200) provides a constant amount of DC offset correction to the analog input signal.

Abstract: A tuned low noise mixer (200) for use in radio frequency (RF) communications includes a transconductance amplifier (203) for amplifying an RF input signal (201). An impedance matching network (207) is formed using an impedance matching transformer with a tap connection (207') between primary and secondary coils. A mixer circuit (209) is then used for mixing a local oscillator signal (211) with the output of the impedance matching network (207) while a load network (213) provides a load to an output (215) of the mixer circuit (209). The invention provides a novel RF mixer topology that has a substantially low noise figure and a proportionally large power gain with low current drain for eliminating the need for an low noise amplifier (LNA) commonly used in RF mixer circuitry.

Abstract: A quadrature generator (100) includes a phase detector (125) having a set of differential inputs for coupling in-phase and quadrature signals (114,116) and a set of differential outputs for providing a phase error signal (135). Switches (122,127) are associated with the set of input terminals and with the set of output terminals. The switches (122,127) are synchronously controlled to switch around the signals at the input terminals and at the output terminals in concert, and in rapid succession. The operation of the switches (122,127) eliminates or reduces the effects of imperfections within the parallel paths of the phase detector circuitry (125), in order to produce a more accurate phase deviation signal.

Abstract: Second order intermodulation distortion (IM2) occurs when two interfacing signals mix with each other through a second order nonlinearity to produce an intermodulation product at the sum and difference frequencies of the two interferers. To reduce the amount of intermodulation distortion, dynamic matching is employed. In practice, dynamic matching operates to transform coefficients of IM2 distortion from constant values into functions of time where they may be handled by known rejection techniques.

Abstract: A baseband demodulator receives inphase and quadrature signals I (116) and Q (117) representing a phase angle and amplitude. The demodulator (114) includes a discrete time continuous amplitude circuit (223, 253, 260) coupled to the quadrature generator to extract a sign information by processing the quadrature components (116 and 118). An accumulator 404 uses the sign information to manipulate predetermined phase angles stored at a memory component 402 to determine the phase angle carried by the I and Q components (116 and 118). As such, the need for up converters or complex analog-to-digital converters is eliminated in direct conversion receivers.

Abstract: To generate a fixed frequency offset in a direct conversion receiver (200) a phase ramp representing the frequency offset if generated. This phase ramp is combined with the demodulated phase component of a received signal. A phase wrap detection and compensation circuit (224) is capable of detecting and compensating for phase wrap that occur in the phase ramp by differentiating the input and detecting when a phase wrap is about to occur and causes a switch (316) to flip between two conditions. A first condition couples the phase ramp to the output. A second condition compensates when a wrap around has been detected. As such, a VCO (218) produces a local oscillator having a fixed frequency offset that is immune from locking problems that occur when a phase wrap is introduced.