One or more hardware identity circuits (which may be reconfigurable) may be employed in a device or system in order to impose a tampering penalty, preferably without relying on battery-backed volatile memory to do so. The device or system may also include a cryptographic division and distribution (‘sharing’) of a secret internal to the device or system.
Systems and methods permit automatic joining of a network associated with a specified area within which wireless nodes reside. Network managers located in or near the specified area use wireless proximity detection to estimate distances to wireless nodes requesting to join the network. The network managers can use the estimated distances to determine whether or not a requesting wireless node is located within the specified area. If the requesting wireless node is located within the specified area, the network managers can permit the wireless node to join the wireless network associated with the respective specified area.
Systems and methods for optically measuring displacement of an element include an emitter for emitting an optical signal, a first detector for detecting reflections of the optical signal from the element, a second detector for detecting reflections of the optical signal from a raised cover structure, a processor for receiving the detected reflections from the first and second detectors and removing distortions in the detected reflections from the first detector using the detected reflections from the second detector.
A device comprising: a physical unclonable function (PUF) device configured to generate an output value based on hardware characteristics of the PUF device; and a processor connected to the PUF device, the processor configured to: execute a cryptographic operation in a sequence of ordered stages including a first stage and a second stage, the executing comprising: in the first stage: recovering a first secret value based on a first output value obtained from the PUF device; executing a first sub-operation using the first secret value; and removing unobscured values from memory prior to execution of a subsequent stage; in the second stage: recovering a second secret value based on a second output value obtained from the PUF device; and executing a second sub-operation using the second secret value to enable execution of a cryptographic operation encoded with at least the first secret value and the second secret value.
Gain independent reference channel measurement system and method. A method of making robust, stable measurements, in a variety of different applications is disclosed. More specifically, this disclosure describes systems and methods relating to performing gain independent reference channel measurements by making two phase measurements of a device under test. Mathematically, the measurements are combined and many common mode parameters drop out. The result yields an analysis of a device under test analysis which mitigated errors, predominately arising from environmental variations and changes in circuit behavior stemming from swings in signal input.
Microelectromechanical systems (MEMS) devices are described that include a proof mass movably connected to a substrate by accordion springs disposed on opposite sides of the proof mass, with a coupler coupling two of the accordion springs together. The coupler is a bar in some implementations, and may be rigid. The coupler therefore restricts the motion of the accordion springs relative to each other. In this manner, the motion of the proof mass may be restricted to preferred types and frequencies.
Variable gain amplifiers (VGA) with output phase invariance are provided herein. In certain embodiments, a VGA is operable in a selected gain setting chosen from multiple gain settings that provide different amounts of amplification to a radio frequency (RF) input signal. The VGA includes a gain transistor that has a substantially constant bias current across the gain settings, such that the VGA's output phase, input impedance matching, and/or input return loss are substantially constant. The gain setting of the VGA is selected by controlling relative biasing of a pair of cascode transistors each connected to the gain transistor by a corresponding degeneration resistor. The degeneration resistors provide compensation that reduces or eliminates a difference in output phase of the VGA across gain settings, for instance, by introducing a zero in a transfer function of the VGA that cancels a pole arising from the cascode transistors.
Sense amplifiers for use in connection with microelectromechanical system (MEMS) gyroscopes are described. The sense amplifiers may be configured to change the level of a gyroscope signal, i.e., the signal produced by a gyroscope in response to angular motion, to a level suitable for processing circuitry arranged to infer the angular velocity. The sense amplifier may further provide a DC discharge path allowing for discharge of the DC component of the output signal. The DC discharge path may include an anti-aliasing filter and a resistive circuit. The anti-aliasing filter may filter the output signal to maintain the resistive circuit in the linear region. The anti-aliasing filter may be designed with a frequency response such that discrete frequency sub-bands are blocked or at least attenuated. The frequency sub-bands may be tuned to substantially match the gyroscope's resonant frequency and its integer multiples.
Multiplying digital-to-analog converter (MDACs) are implemented in pipelined ADCs to generate an analog output being fed to a subsequent stage. A switched capacitor MDAC can be implemented by integrating a capacitor digital-to-analog converter (DAC) with charge pump gain circuitry. The capacitor DAC can implement the DAC functionality while the charge pump gain circuitry can implement subtraction and amplification. The resulting switched capacitor MDAC can leverage strengths of nanometer process technologies, i.e., very good switches and highly linear capacitors, to achieve practical pipelined ADCs. Moreover, the switched capacitor MDAC has many benefits over other approaches for implementing the MDAC.
Wideband baluns with enhanced amplitude and phase balance are provided. The wideband balun includes a first transmission line connected between a first port and a third port, and a second transmission line connected between a second port and a fourth port, and a third transmission line connected between the third port and a reference voltage, such as ground. To enhance phase and/or amplitude balance of the wideband balun, the wideband balun further includes a compensation structure operable to provide at least one of capacitive compensation or inductive compensation to balance the wideband balun. For example, in certain implementations, the compensation structure includes at least one of (i) a capacitor connected between the first port and the second port or (ii) a fourth transmission line connected between the first transmission line and the third port.
An example current mirror arrangement includes a first portion and a second portion, each of which includes a current mirror having transistors Q1 and Q2, a buffer amplifier that has an input coupled to a base/gate terminal of Q1 and an output coupled to a base/gate terminal of Q2, a master resistor coupled to an emitter/source terminal of Q1, and a slave resistor coupled to an emitter/source terminal of Q2. Furthermore, the slave resistor of the first portion is coupled to the slave resistor of the second portion. Providing additional resistors on master and slave sides of a current mirror arrangement may advantageously allow benefiting from the use of buffers outside of a feedback loop of a current mirror while reducing the sensitivity of the current mirror arrangement to buffer offsets.
A MEMS resonant accelerometer includes two proof masses configured to resonate when driven with periodic signals. Each proof mass includes a resonator structure that vibrates relative to the proof mass and a dummy structure that does not resonate. When driven by a periodic drive signal, the resonator structures of the two proof masses may be used to determine the magnitude of acceleration in the direction perpendicular to the planes of the proof masses by sensing the frequency at which the resonators vibrate. For example, a differential oscillation frequency may be computed from the two sensed frequencies. The dummy structures are used to make the mass distribution of the two proof masses similar.
An integrated gesture sensor module includes an optical sensor die, an application-specific integrated circuit (ASIC) die, and an optical emitter die disposed in a single package. The optical sensor die and ASIC die can be disposed in a first cavity of the package, and the optical emitter die can be disposed in a second cavity of the package. The second cavity can be conical or step-shaped so that the opening defining the cavity increases with distance from the upper surface of the optical emitter die. The upper surface of the optical emitter die may be higher than the upper surface of the optical sensor die. An optical barrier positioned between the first and second cavities can include a portion of a pre-molded, laminate, or ceramic package, molding compound, and/or metallized vias.
Capped microelectromechanical systems (MEMS) devices are described. In at least some situations, the MEMS device includes one or more masses which move. The cap may include a stopper which damps motion of the one or more movable masses. In at least some situations, the stopper damps motion of one of the masses but not another mass.
Optical systems can emit train(s) of light pulses onto objects to derive a distance between the light source and the object. Achieving meter or centimeter resolution may require very short light pulses. It is not trivial to design a circuit that can generate narrow current pulses for driving a diode that emits the light pulses. An improved driver circuit has a pre-charge path comprising one or more inductive elements and a fire path comprising the diode. Switches in the driver circuit are controlled with predefined states during different intervals to pre-charge current in the one or more inductive elements prior to flowing current through the fire path to pulse the diode.
Disclosed herein are systems and techniques for serial peripheral interface (SPI) functionality for node transceivers in a two-wire communication bus. For example, in some embodiments, a node transceiver may include SPI circuitry and upstream or downstream transceiver circuitry. SPI commands received via the SPI circuitry may be executed by the node transceiver, or transmitted upstream or downstream along the two-wire bus for execution by another node transceiver or a slave device coupled to another node transceiver.
Disclosed herein are systems and techniques for general purpose input/output (GPIO)-to-GPIO communication in a multi-node, daisy-chained network. In some embodiments, a transceiver may support GPIO between multiple nodes, without host intervention after initial programming. In some such embodiments, the host may be required only for initial setup of the virtual ports. In some embodiments, GPIO pins can be inputs (which may change virtual ports) or outputs (which may reflect virtual ports). In some embodiments, multiple virtual ports may be mapped to one GPIO output pin (with the values OR'ed together, for example). In some embodiments, multiple GPIO input pins may be mapped to one virtual port. For example, multiple GPIO input pin values may be OR'ed together, even if they come from multiple nodes.
Improved track and hold (T/H) circuits can help analog-to-digital converters (ADCs) achieve higher performance and lower power consumption. The improved T/H circuits can drive high speed and interleaved ADCs, and the design of the circuits enable additive and multiplicative pseudo-random dither signals to be injected in the T/H circuits. The dither signals can be used to calibrate (e.g., linearize) the T/H circuits and the ADC(s). In addition, the dither signal can be used to dither any remaining non-linearity, and to calibrate offset/gain mismatches in interleaved ADCs. The T/H circuit design also can integrate an amplifier in the T/H circuit, which can be used to improve the signal-to-noise ratio (SNR) of the ADC or to act as a variable gain amplifier (VGA) in front of the ADC.
System and apparatus for portable gas detection. Specifically, this disclosure describes apparatuses and systems for optical gas detection in a compact package. There is a need for a very compact, low-power, gas detection system for gases such as CO2, NOx, water vapor, methane etc. This disclosure provides an ultra-compact and highly efficient optical measurement system based on principals of optical absorption spectroscopy. It reduces the size of the instrument as well its power consumption by more than an order of magnitude making it possible to deploy it widely. There is an identified need for large number of distributed gas sensors to improve human health, environment, and save energy usage.