Nxp B.v.

Quintic Holdings

Koninklijke Philips Corporation N.v.

Yifeng Zhang

Peiqi Xuan

Tracey Lee Chavers

Qifa Wu

Jie Zhang

Vasanth Reddy Gaddam

Yuanwei Wu

Guanqing Wang

Hangwei Guo

Tao N Zhang

Charles John Razzell

Jianjun Zhang

Kou-Hu Tzou

Kanyu Cao

Fuquan Zhang

Xiaodong Jin

Xuechu Li

Henk Visser

Tianbao Liang

Pengyi Hong

Shuchen Xie

A method and apparatus for activity tracking based on time domain and frequency domain processing are disclosed. Embodiments according to the present invention are used to improve the accuracy of activity detection and step counting. The activity tracking starts from sample collection to generate 3-D accelerometer data. By pre-processing, the 3-D accelerometer data is calibrated and filtered. Then, the dominant component is calculated and statistical attributes or features used for activity detection are extracted. The statistical attributes are derived from time domain sensor data, frequency domain transformed data, or both. A classifier is developed using representative training data set. The activity detector determines the current activity status based on the statistical attributes and the classifier. To further refine the activity, post-processing is performed on the activity status.

Time and frequency domain based activity tracking system

A system for counting steps comprising a 3-D accelerometer is disclosed. The system also includes a pre-processor module coupled to the 3-D accelerometer and a dominant component computation unit coupled to the pre-processor module. The dominant component computation unit is configured to identify a dominant component in an output of the 3-D accelerometer. The system further includes a step counter for counting a number of steps using the output of the dominant component computation unit. The step counter includes a Fast Fourier Transform (FFT) module and a direct current (DC) remover module to remove a static component from the output of the FFT module. The step counter also includes a derivative filter and a zero crossing detector.

Time and frequency domain based step counter

Embodiments of a method for communicating in a wireless mesh network, a method for communicating in a Bluetooth Low Energy (BLE) mesh network, and a wireless communications device are described. In one embodiment, a method for communicating in a wireless mesh network involves at a first wireless communications device, scanning the wireless mesh network for a unit time period to discover a first transmission time slot within the unit time period that is used by a second wireless communications device in the wireless mesh network, at the first wireless communications device, choosing a second transmission time slot within the unit time period for the first wireless communications device, where the second transmission time slot is different from the first transmission time slot, and from the first wireless communications device, broadcasting data in the wireless mesh network in the second transmission time slot within a subsequent unit time period.

Method and system for communicating in a wireless mesh network

FM radio transmitter is being widely used in portable devices as a convenient way to output audio contents to ubiquitously available FM radio receivers in cars or homes. However, the signal from the FM radio transmitter may be interfering with the signal being broadcast by an FM radio station. A scan system is incorporated into the FM radio transmitter to quickly and reliably identify a vacant channel for the FM radio transmitter to use. The scan system measures on-channel and out-of-channel signal quality and selects a best channel for transmission based on the measured on-channel and out-of-channel signal quality. The scan system is also incorporated into an FM radio receiver to quickly and reliably tune to a valid channel. The scan system selects the valid channel based on the measured on-channel and out-of-channel signal quality.

Radio transmitter and radio receiver with channel condition assessment

A method of the present invention includes coordinating tuning to the same channel of a radio band wherein the following steps are performed: tuning to a channel, within a radio band, that uses a side band; receiving control information in the side band of the channel; and processing the received audio information in the channel using the control information.

Channel coordination between a wireless earphone and a transmitter

In an embodiment of the present invention, a clock generator circuit is disclosed to include a phase locked loop (PLL) that is responsive to a reference frequency and operative to generate a single clock frequency and a clock signal quadrature output frequency and a clock signal in-phase output with the frequency of the clock signal quadrature output frequency and the clock signal in-phase output frequency being a fraction of the frequency of the single clock frequency. The PLL includes a single voltage controlled oscillator (VCO) that generates the single clock frequency. A plurality of dividers is included in the clock generator circuit and is responsive to the clock signal quadrature output frequency and the clock signal in-phase output frequency and generates multiple clock frequencies, each clock frequency being a unique frequency, each of the plurality of dividers generating an output, the final output of the plurality of dividers being synchronized to the reference frequency.

Single-clock-based multiple-clock frequency generator

A scan system receives signals within a band from an antenna and divides the band into sub-bands and scans the channels of each sub-band to determine a candidate channel based on the lowest figure of merit (FOM) and includes an on-channel selection block responsive to a received digital signal and operative to select only the on-channel frequencies and to substantially disregard the out-of-channel frequencies from the digital signal. The scan system generates a FOM on-channel signal representing a measurement of the signal quality of the on-channel signal and includes an out-of-channel selection block responsive to the digital signal and operative to select only the out-of-channel frequencies and to substantially disregard the on-channel frequencies from the digital signal and operative to generate a FOM out-of-channel signal representing a measurement of the signal quality of the out-of-channel signal.

Frequency modulation (FM) clear channel scanning system and method of using same

A device and method of duplex audio communication over a broadcast channel are disclosed. Low-power transmission over a broadcast channel is permissible for personal use as long as the transmitted power level is below a level allowed by respective regulatory. For example, low-power FM transmitter can be used to provide a wireless audio link between two audio devices. One such application scenario is a wireless speakerphone used as an audio extension from a cellphone for group conference purposes. Such applications face issues of potential interference from other users of the same channel and the need of manually selecting and tuning a pair of channels. The device and method disclosed in the present invention use the clear channel technique to automatically select an un-occupied channel for the transmit side and utilizes an identification embedded in a sub-channel to allow the receiver to automatically tune to the channel used by the transmitter. The clear channels may be determined by respective transceivers or determined by a master transceiver.

System and method of duplex wireless audio link over broadcast channels

Systems of clock generation for integrated radio frequency receiver. In an integrated radio frequency receiver, a mixer is often used to down convert the incoming radio frequency signal. The down converted signal is then digitized and digital signal processing circuitry is used for efficient and flexible implementation of various functions to receive the underlying audio and/or data information. The mixer requires clock generation circuitry to provide a proper local oscillator signal for a selected channel. On the other hand, the digital signal processing circuitry requires its separate digital clock for proper operations. The clock generation system utilizes single local oscillator generation circuitry to provide the local oscillator signals required by the mixer and the digital clock signals required by the digital signal processing circuitry. In order to maintain a fixed frequency for the digital clock signal regardless channel selection, a fractional divider coupled with sigma-delta circuitry is used to derive the digital clock signal.

Clock generation for integrated radio frequency receivers

Systems and methods of clock generation for radio frequency receiver. In radio frequency receiver, the system requires accurate local oscillating (LO) signal and system clocks for proper operation and to ensure high quality performance. In order to achieve accurate LO frequency and system clock, a crystal or and accurate reference clock is provide to the clock generation circuit. How a low-cost receiver, it is desirable to eliminate the requirement for a crystal or an accurate reference clock. The present invention discloses systems and methods to utilize a pilot signal embedded in the transmitted signal. The pilot signal usually has very accurate frequency which is particular true for broadcast system such as FM broadcast. In various embodiments of the present invention, the systems and methods measure the relation between the frequency of the pilot signal and the current clock generated. The measured result is compared with a know relation corresponding to the frequency of the pilot signal and the target clock signal and the result is used to adjust the clock generation circuit.

Crystal-less clock generation for radio frequency receivers

Systems and methods according to the present invention provide channel estimation methods, systems and devices which determine a coarse channel estimate () and a fine channel estimate (). The coarse channel () estimate can be determined based on the channel estimation sequence transmitted to the receiver and then used to detect header symbols. The header symbols can be used to calculate additional channel estimates which can then be combined with the coarse channel estimate () to determine a fine channel estimate ().

Methods and apparatus for channel estimation for wideband OFDM communication systems

Clear channel assessment (CCA) is a very important issue in Ultra-Wideband (UWB) systems. An effective CCA mechanism will have a large impact on the overall throughput of the communications system. It is disclosed methods and circuits to carry out CCA determinations exploiting the structure of the pulse signal either by using a moving average or by performing a cross-correlation with a locally generated signal.

Clear channel assessment (CCA) for UWB communications system

A transmitter and/or receiver includes a single crystal clock oscillator circuit and a sample rate converter (SRC) that selectively generates samples at an alternative frequency for subsequent transmission or decoding. A 40 MHz crystal provides the clock signal for the digital-to-analog and analog-to-digital converters that are used to convert the samples to and from analog form. In an IEEE 802.11-compatible embodiment, the 802.11a compatible 20 MHz OFDM samples are converted to and from analog form directly, whereas a sample rate converter converts the 802.11b compatible 22 MHz DSSS samples to and from 40 MHz samples to provide compatibility with the 40 MHz analog conversions.

Single oscillator DSSS and OFDM radio receiver

A quadrature transmitter and receiver have configurable I and Q channel paths that facilitate the application of selected test signals to determine gain and phase imbalances introduced by the transmitter and receiver. In a first 'normal' configuration, the I and Q channels are independently tested by applying an I-only test signal, followed by a Q-only test signal. In a second 'switched transmitter' configuration, the Q-only test signal is again applied. In a third &#x2018;switched receiver&#x2019; configuration, the I-only test signal is again applied. By combining the results, gain and phase imbalances of the transmitter and the receiver can be determined. In a preferred embodiment, these configurations and test signals are applied within a single transceiver that has the output of its transmitter closed-loop coupled to the input of its receiver.

Growing community of inventors

San Jose, CA, United States of America

Yifeng Zhang