A system is described for maintaining synchrony of operations among a plurality of devices having independent clocking arrangements. A task distribution device is to distribute tasks to a synchrony group comprising a plurality of devices to perform tasks distributed by the task distribution device in synchrony. The task distribution device distributes each task to synchrony group members over a network. Each task is associated with a time stamp that indicates a time, relative to a clock maintained by the task distribution device, at which synchrony group members are to execute the task. Each synchrony group member periodically obtains from the task distribution device an indication of current time indicated by its clock, determines a time differential between the task distribution device's clock and its respective clock and determines therefrom a time at which, according to its respective clock, the time stamp indicates that it is to execute the task.

System and method for synchronizing operations among a plurality of independently clocked digital data processing devices

Carrier Interferometry (CI) provides wideband transmission protocols with frequency-band selectivity to improve interference rejection, reduce multipath fading, and enable operation across non-continuous frequency bands. Direct-sequence protocols, such as DS-CDMA, are provided with CI to greatly improve performance and reduce transceiver complexity. CI introduces families of orthogonal polyphase codes that can be used for channel coding, spreading, and/or multiple access. Unlike conventional DS-CDMA, CI coding is not necessary for energy spreading because a set of CI carriers has an inherently wide aggregate bandwidth. Instead, CI codes are used for channelization, energy smoothing in the frequency domain, and interference suppression. CI-based ultra-wideband protocols are implemented via frequency-domain processing to reduce synchronization problems, transceiver complexity, and poor multipath performance of conventional ultra-wideband systems. CI allows wideband protocols to be implemented with space-frequency processing and other array-processing techniques to provide either or both diversity combining and sub-space processing. CI also enables spatial processing without antenna arrays. Even the bandwidth efficiency of multicarrier protocols is greatly enhanced with CI. CI-based wavelets avoid time and frequency resolution trade-offs associated with conventional wavelet processing. CI-based Fourier transforms eliminate all multiplications, which greatly simplifies multi-frequency processing. The quantum-wave principles of CI improve all types of baseband and radio processing.

Multicarrier sub-layer for direct sequence channel and multiple-access coding

In general, user interfaces for controlling a plurality of multimedia players in groups are disclosed. According to one aspect of the present invention, a user interface is provided to allow a user to group some of the players according to a theme or scene, where each of the players is located in a zone. When the scene is activated, the players in the scene react in a synchronized manner. For example, the players in the scene are all caused to play a multimedia source or music in a playlist, wherein the multimedia source may be located anywhere on a network. The user interface is further configured to illustrate graphically a size of a group, the larger the group appears relatively, the more plays there are in the group.

User Interfaces for Controlling and Manipulating Groupings in a Multi-Zone Media System

Radio-frequency (RF) integrated circuit (RFIC) chip(s) allow for the integration of multiple electronic circuits on a chip to provide distributed antenna system functionalities. RFIC chips are employed in central unit and remote unit components, reducing component cost and size, increasing performance and reliability, while reducing power consumption. The components are also easier to manufacture. The RFIC chip(s) can be employed in distributed antenna systems and components that support RF communications services and/or digital data services.

Radio-frequency integrated circuit (rfic) chip(s) for providing distributed antenna system functionalities, and related components, systems, and methods

The present invention relates to a method for wireless transmission of data between components of a blood glucose system (1, I1) including a master controller (2, 2') having a receiver (10) and a transmitter (9), and at least one slave device (3) having a receiver (19) and a transmitter (18), and to a corresponding blood glucose system (1, I1) • The slave device (3) is normally operated in a power saving mode in which its receiver (19) is only activated intermittently at a receiver activation frequency for a predetermined listening period The controller (2, 21) transmits a communication initiation data frame to the slave device (3) by means of a signal comprising a preamble signal transmitted for a preamble period Upon receipt of the communication initiation data frame, the slave device (3) is switched to a communication mode in which it transmits a response to the controller (2, 21), and the slave device (3) is switched from the communication mode to the power saving mode Initially the receiver activation frequency is set to a first frequency value upon switching from communication mode to power saving mode, and then to a second frequency value smaller than the first frequency value if no communication initiation data frame is received for a predetermined power saving timeout period The communication initiation data frame is transmitted such that the preamble period exceeds the length of the cycle duration corresponding to the first frequency value, and, in case no response is received by the controller during the response period, the communication initiation data frame is adapted and retransmitted such that the preamble period is increased and exceeds the length of the cycle duration corresponding to the second frequency value

Method for transmitting data in a blood glucose system and corresponding blood glucose system

Apparatus, system and method for synchronizing one or more clocks across a communication link. A slave clock may be synchronized to a master clock by means of a synchronization signal sent from the master to the slave clock side of the link. The synchronization signal may be an expected signal pattern sent at intervals expected by the slave side. The slave clock may correlate received signals with a representation of the expected synchronization signal to produce a correlation sample sequence at a first sample rate which is related as n times the slave clock rate. The synchronization signal receipt time indicated by the correlation sample sequence may be refined by interpolating the correlation sample sequence around a best correlation sample to locate a best interpolation at an interpolation resolution smaller than the sample resolution. The best interpolation may in turn be further refined by estimating between interpolator outputs adjacent to the best interpolation output. The synchronization signal receipt time thus determined is compared to the expected time based upon the slave clock, which is adjusted until the times match. After initialization, all slave clock errors are preferably accumulated to prevent long-term slip between the slave and master clocks. Formerly independent master and slave clocks synchronized across the communication link constitute a noncommon clock which may be compared on each side of the link to secondary independent clocks, and the secondary independent clocks may then be separately synchronized by adjusting one to have the same difference from its local noncommon clock as the secondary clock on the other side of the link has from its local noncommon clock.

Synchronizing clocks across a communication link

A method of simplifying the encoding of a predetermined number of bits of data into frames including adding error coding bits so that a ratio of the frame length times the baud rate of the frame times he bit packing ratio of the data divided the total bits of data is always an integer. The method may also convolutionally encode the bits of data so that the same equation is also always an integer.

Frame structure for an adaptive modulation wireless communication system

A system and method for enhancing the performance of an equalizer in a modem. Multiple techniques are disclosed which improve the modem performance. A first technique uses stored parameters for each burst from each remote site to demodulate a received data stream. A second technique compensates for the gain droop caused by storing parameters across each burst. A third technique minimizes errors caused by adapting the equalizer coefficients for each data burst by analyzing the SN ratio and error rate of the received burst. A fourth technique improves the convergence of the equalizer by using a two-part preamble, whereby both parts are transmitted using different modulation techniques. A fifth technique is provided which performs a soft reset of the modem without performing a complete reset of the modem. A sixth technique determines a modem adaptation factor based on the expected modulation type of an incoming burst transmission. A seventh technique calculates a phase correction value for the stored tap values and applies the value to the incoming signal.

Equalizer performance enhancements for broadband wireless applications

A method of assigning downlink time slots to receive units where the units may generate data using different modulation schemes. The method preferably assigns the downlink time slots as a function of the complexity of modulation schemes employed by the units. Further, the method preferably assigns the time slots from the least complex modulation scheme to the most complex scheme. The method may further assign uplink time slots to transmit units where the transmit units may generate data using different modulation schemes. The method preferably assigns the uplink time slots as a function of the complexity of modulation schemes employed by the uplink units. Further, the method preferably assigns the uplink time slots from the least complex modulation scheme to the most complex scheme. In other embodiments, the downlink time slots are assigned as a function of the bit per symbol rate employed by the receive units, preferably from the lowest bit per symbol rate to the highest bit per symbol rate. Further, the uplink time slots are assigned as a function of the bit per symbol rate employed by the transmit units, preferably from the lowest bit per symbol rate to the highest bit per symbol rate. The present invention is also a method of simplifying the encoding of a predetermined number of bits of data into frames. The method adds error coding bits so that a ratio of the frame length times the baud rate of the frame times the bit packing ratio of the data divided the total bits of data is always an integer. The method may also convolutionally encode the bits of data so that the same equation is also always an integer. The present invention is also a method of updating the weights of a FIR filter where the filter processes symbols having variable modulation rates. When the modulation rate of the incoming symbols changes, the weights corresponding to the first symbol having the new modulation rate are changed based as the symbol propagates through the filter.

Improved frame structure for an adaptive modulation wireless communication system

The present invention relates to a method of updating the weights of a FIR filter where the filter processes symbols having variable modulation rates. When the modulation rate of the incoming symbols changes, the weights corresponding to the first symbol having the new modulation rate are changed based as the symbol propagates through the filter.

Frederick W. Price

Papers

Synchronizing clocks across a communication link

Frame structure for an adaptive modulation wireless communication system

Equalizer performance enhancements for broadband wireless applications

Improved frame structure for an adaptive modulation wireless communication system

Finite impulse response filtering for an adaptive modulation wireless communication system