Abstract: The present disclosure relates to systems and methods for probabilistically estimating an individual's pulse rate in the presence of nontrivial noise spectra. In one implementation, the method may include receiving a set of signals from a set of sensors associated with the device, the set of signals including a photoplethysmographic (PPG) signal obtained from the individual; transforming the PPG signal to the frequency domain; applying a band-pass filter to the transformed signal to generate a filtered signal; identifying one or more peaks in the filtered signal; generating a set of one or more sample classifiers for each peak in the set of one or more peaks; and comparing the set of sample classifiers to a set of library classifiers included in a learning library. Each library classifier is associated with a classification coefficient reflecting a degree of correlation between the library classifier and a known pulse rate profile.

Abstract: An apparatus includes a light source, a display array, a light relay, a photodetector, and control circuitry. The light source is for providing lamp light during an ON-time of the light source. The display array is positioned to receive and selectively manipulate the lamp light. The light relay is positioned to receive the image light from the display array. Control circuitry is coupled to the light source for adjusting the light source and coupled to receive an output of the photodetector.

Abstract: An apparatus includes a light source, a display array, a light relay, a photodetector, control circuitry, and measurement circuitry. The light source is for providing lamp light during an ON-time of the light source. The display array is positioned to receive and selectively manipulate the lamp light. The light relay is positioned to receive the image light from the display array. The photodetector is optically coupled to receive light. Control circuitry is coupled to the light source for cycling the light source and coupled to the measurement circuitry for coordinating light measurements of the photodetector.

Abstract: A system configured to detect faults in signal lines. A system includes a first component configured to communicate with a second component via a signal path including one or more signal traces. Sense signal lines are manufactured such that at some point they are in close proximity to a signal trace which is to be monitored. The sense signal lines are configured to use parasitic coupling to redirect a portion of a signal conveyed via a signal trace to a monitoring component. The first component is configured to convey a test signal indicative of a type of test via the signal path, and a reference signal to the monitoring component. The monitoring component is configured to utilize the reference signal to ascertain a presence or absence, or characteristics of a received redirected signal. The monitoring component may optionally utilize a locally generated reference signal.

Abstract: A method and apparatus for thermally isolating a temperature sensor mounted on a printed circuit board from a heat generating component mounted on the printed circuit board is provided. Generally, a thermal isolation region, which may be comprised of a plurality of openings in the printed circuit board, is disposed about the temperature sensor to interrupt conductive transfer of heat from the heat generating component to the temperature sensor. The openings extend sufficiently far into the printed circuit board to remove at least a portion of a conductive layer, such as a power plane from the region surrounding the temperature sensor. Electrical power and signals may be provided to the temperature sensor through regions intermediate the openings.

Abstract: A method is provided for controlling transitions between a first and second clock frequency signal in first and second components electrically coupled together and in communication with one another. The method comprises asserting a freeze signal to cause communications between the first and second components to cease. A freeze acknowledge signal is then received from the first and second components, indicating that communications therebetween have ceased. A change signal is delivered to the first and second components to cause the components to switch between the first and second clock frequency signals.

Abstract: A method for operating a cache having a sleep mode is provided. The cache is located within a memory hierarchy of a computer system, and the method is comprised of receiving a first cache request, and servicing the first cache request. A sleep mode signal is asserted in response to completion of the servicing of the first cache request. Thereafter, a second cache request is received, and the sleep mode signal is deasserted in response to receiving the second cache request. Thereafter, the second cache request is serviced.

Abstract: An option module that may be installed in a computer system is provided. The option module includes functional circuitry that is accessed by the computer system through a conventional connector and/or bus. A nonvolatile memory is also included on the option module and is used to store a variety of system information, such as serial numbers. At least a portion of this system information is protected from alteration by the computer system. A second connector is also provided on the option module. An external device when coupled to the second connector may access all of the system data, and, if desired, alter it. Moreover, the option module need not be installed in the computer system for the external device to access the contents of the memory through the second connector.

Abstract: A method for controlling thermal cycles in a computer system is provided. The method is comprised of receiving a request to transition the computer system from a first operating mode to a second operating mode, where less power is consumed in the second operating mode. A historical rate at which the computer system has transitioned between the first and second operating modes is determined, and the requested transition is permitted in response to the historical rate being less than a first preselected setpoint, but denied in response to the historical rate being greater than the first preselected setpoint.

Abstract: A method for controlling operation of a bus and components coupled thereto is provided. The method is comprised of receiving a request for a bus transaction from one of the components coupled to the bus. Thereafter, the frequency of a clock signal supplied to at least the requesting component is increased, and the requested bus transaction is serviced. The frequency of the clock signal supplied to at least the requesting component is decreased upon completion of the requested bus transaction.

Abstract: In one aspect of the present invention, a method for controlling the operation of a phase locked loop circuit is provided. The method is comprised of monitoring a frequency of a system clock, and a first signal is delivered in response to the detected frequency of the system clock being greater than a preselected setpoint. A second signal is delivered in response to the detected frequency of the system clock being less than a preselected setpoint. A first operating mode of the phase locked loop circuit is selected in response to receiving the first signal. The first mode of operation allows the phase locked loop circuit to synchronize with a clock signal in a first preselected range of frequencies. A second operating mode of the phase locked loop circuit is selected in response to receiving the second signal. The second mode of operation allows the phase locked loop circuit to synchronize with a clock signal in a second preselected range of frequencies.

Abstract: A phase locked loop circuit is provided. The phase locked loop circuit is comprised of a first and second divide-by-N counter, a phase comparator, a voltage controlled oscillator, a clock tree, and a feedback path. The first divide-by-N counter is adapted to receive a first clock signal and provide a second clock signal. The phase comparator has a first and second input terminal and an output terminal. The phase comparator is adapted to compare the phase of signals applied to the first and second input terminals and deliver a signal at the output terminal having a magnitude indicative of a difference in the phases of the signals. The first input terminal is coupled to receive the second clock signal. The voltage controlled oscillator is coupled to receive the phase difference signal and deliver a third clock signal having a frequency responsive thereto. The second divide-by-N counter is coupled to receive the third clock signal and deliver a fourth clock signal.

Abstract: A method and apparatus for thermally isolating a temperature sensor mounted on a printed circuit board from a heat generating component mounted on the printed circuit board is provided. Generally, a thermal isolation region, which may be comprised of a plurality of openings in the printed circuit board, is disposed about the temperature sensor to interrupt conductive transfer of heat from the heat generating component to the temperature sensor. The openings extend sufficiently far into the printed circuit board to remove at least a portion of a conductive layer, such as a power plane from the region surrounding the temperature sensor. Electrical power and signals may be provided to the temperature sensor through regions intermediate the openings.

Abstract: A memory system is provided. The memory system is comprised of a memory, a clock signal generator, a phase locked loop circuit, and a bypass circuit. The clock signal generator produces a first clock signal. The clock signal generator has a first mode of operation in which the first clock signal has a first frequency and a second mode of operation in which the first clock signal has a second frequency. The phase locked loop circuit is associated with the memory and adapted for receiving the first clock signal and providing a synchronized second clock signal to the memory. The bypass circuit is adapted to deliver the first clock signal to the memory in the second mode of operation.

Abstract: A method is provided for operating an electronic device by monitoring operating characteristics of the electronic device, and determining from the monitored operating characteristics to operate at least a portion of components within the electronic device in a first, second, or third mode of operation. The first, second, and third modes of operation consume power at first, second, and third different rates. At least a portion of the components are instructed to switch between the first, second, and third modes.

Abstract: A method and apparatus for thermally isolating a temperature sensor mounted on a printed circuit board from a heat generating component mounted on the printed circuit board is provided. Generally, a thermal isolation region, which may be comprised of a plurality of openings in the printed circuit board, is disposed about the temperature sensor to interrupt conductive transfer of heat from the heat generating component to the temperature sensor. The openings extend sufficiently far into the printed circuit board to remove at least a portion of a conductive layer, such as a power plane from the region surrounding the temperature sensor. Electrical power and signals may be provided to the temperature sensor through regions intermediate the openings.

Abstract: A power supply is provided. The power supply is comprised of a first power module, a second power module, and a controller. The first power module is capable of delivering a first preselected amount of power. The second power module is capable of delivering a second preselected amount of power. The first and second power modules are coupled together to be capable of delivering an aggregate amount of power related to the first and second preselected amounts of power. The controller is adapted to selectively enable the first and second power modules to make power available in one of the first preselected amount, the second preselected amount, and the aggregate amount.

Abstract: An option module that may be installed in a computer system is provided. The option module includes functional circuitry that is accessed by the computer system through a conventional connector and/or bus. A nonvolatile memory is also included on the option module and is used to store a variety of system information, such as serial numbers. At least a portion of this system information is protected from alteration by the computer system. A second connector is also provided on the option module. An external device when coupled to the second connector may access all of the system data, and, if desired, alter it. Moreover, the option module need not be installed in the computer system for the external device to access the contents of the memory through the second connector.

Abstract: A method and apparatus for thermally isolating a temperature sensor mounted on a printed circuit board from a heat generating component mounted on the printed circuit board is provided. Generally, a thermal isolation region, which may be comprised of a plurality of openings in the printed circuit board, is disposed about the temperature sensor to interrupt conductive transfer of heat from the heat generating component to the temperature sensor. The openings extend sufficiently far into the printed circuit board to remove at least a portion of a conductive layer, such as a power plane from the region surrounding the temperature sensor. Electrical power and signals may be provided to the temperature sensor through regions intermediate the openings.

Abstract: A clock circuit for selectively enabling a clock signal to be propagated, via a transmission line, to an option module when the module is coupled to the clock circuit, and for preventing propagation of the clock signal through the transmission line when the option module is decoupled from the clock circuit. The clock circuit includes a clock driving element employed within a first module and a clock receiving element employed within a second module. The clock driving element includes a clock driver, normally an amplifier connected to at least one emitter-follower transistor. A pull-up resistor is coupled to the emitter of the transistor so that, when the option module is decoupled from the transmission line, the pull-up resistor applies voltage sufficient to turn-off the transistor. Otherwise, the pull-up resistor has no effect on the clock circuit.