Abstract: A method (500) and an apparatus (300) are presented for processing a signal in a receiver in accordance with Ultra Wideband (UWB) protocol. The received signal is acquired during a first preamble portion (411) of a data frame associated with the UWB protocol. During acquisition a first Automatic Gain Control (AGC) operation (606) is performed associated with a noise component of the signal. A second AGC operation (608) associated with a pulse component of the signal is performed after the acquiring the signal during a second preamble portion (413).

Abstract: A tracking circuit (100) is provided for controlling a locally-generated clock. A receive channel (110) in the tracking circuit receives an incoming signal and a local clock, generates a local signal based on the local clock, and compares the local signal and the incoming signal to generate a data signal and an unfiltered phase error signal. A loop filter (120) filters the unfiltered phase error signal to provide a filtered phase error signal. A numerically controlled oscillator (140) generates a correction clock based on the filtered phase error signal. And a filter control circuit (160) provides one or more filter control signals to control operational parameters of the loop filter. The correction clock is provided to the receive channel to modify at least one of the phase and frequency of the local clock. In addition, a sample switch (125) may also be provided to sample the unfiltered phase error signal.

Abstract: A method is provided for adjusting timing alignment in which a receiver generates a plurality of imbalanced correction codes (1310), and square waves both having the same frequency. The receiver mixes the imbalanced correction codes with the square waves to create a mixed signal (1320), and integrates the mixed signal over a correction code period to generate a signal power value (1330). The receiver adjusts a phase of the square wave in a first direction when the signal power value satisfies a first criterion (1340, 1350), and in a second direction when the signal power value satisfies a second criterion (1340, 1360). Each imbalanced correction code is symmetrical. And a total integrated value of one of the imbalanced correction codes over the correction code period is either above a first threshold, or below a second threshold, the first threshold being greater than or equal to the second threshold.

Abstract: A method is provided for reducing a DC bias in a receiver. This method includes isolating a second circuit portion from a first circuit portion (535) and determining a second DC bias correction value for the second circuit portion that will eliminate a second DC bias at the isolated second circuit portion (540). The second circuit portion is then connected to the first circuit portion (550) and a bias-maximizing code word is generated at the first circuitry (505). A first DC bias correction value is then determined that will eliminate a first DC bias at the first circuit portion (555). The bias-maximizing code word is formed such that: a first integrated value of a first half of the bias-maximizing code word has a positive value, and a second integrated value of a second half of the bias-maximizing code word over half of the code word length has a negative value.

Abstract: A method and an apparatus are provided for mitigating spectral lines in a wireless signal. First a code word is generated that is made up of a plurality of binary or ternary encoded pulses. Then a plurality of code-word-modulated wavelets are generated in response to the code word. These wavelets can be Gaussian monopulses, repeated cycles of a sine wave, or other shaped impulse signals. The plurality of code-word-modulated wavelets are then modulated with a bit of transmit data to form a plurality of data-modulated wavelets. This modulation serves to whiten the signals since the transmit data is effectively random. Finally, the plurality of data-modulated wavelets are transmitted to a remote device.

Abstract: An equalizer (106, 146) for use in systems such as an asymmetric digital subscriber line (ADSL) transceiver (5) reduces the number of calculations required for updating the equalizer coefficients. The equalizer (106, 146) takes advantage of the substantially symmetrical phase and amplitude distortion of the signal constellation, which causes both the amplitude and the phase relationship of the calculated error term for each constellation point to be equal. Instead of performing a full complex multiplication, the equalizer (106, 146) uses some but not all of the product terms between the real and imaginary components of the calculated error term and the conjugate of the received data estimate in the coefficient update calculation. The result is then scaled to account for the missing terms. The resulting equalizer (106, 146) requires fewer calculations for coefficient updating.

Abstract: A communications system 10 having an Asymmetric Digital Subscriber Line (ADSL) transceiver (24) is provided which may be configured either as a central office or a remote terminal in a system. The transceiver (24) operates in a listen/report idle state to report line activity to a host processor (22) prior to being configured as a central office or remote terminal. The host processor configures the transceiver (24) as a central office, remote terminal, or as otherwise specified based on the line activity.

Abstract: A transceiver (5) for an asymmetric communication system such as asymmetric digital subscriber line (ADSL) includes a configuration register (71) defining operation at either a central office (CO) or a remote terminal (RT). The configuration register (71) includes a control bit (72) for selecting either CO or RT mode. The transceiver (5) includes a signal processing module (70) configured according to the state of the control bit (72). For example, a digital interface (70) converts transmit data into transmit symbols and converts received symbols into receive data. The digital interface (70) uses a large memory (158) as a buffer in the transmit path and a small memory (160) as a buffer in the receive path in CO mode. In RT mode, the digital interface (70) uses the small memory (160) in the transmit path and the large memory (158) in the receive path. The selective configuration allows a single integrated circuit to be used in both CO and RT equipment.

Abstract: A host processor (22) in a communication system (10) identifies a level of program visibility for reporting predetermined activation state changes, and signals a communications transceiver (24) to begin an initialization process. The communications transceiver (24) begins executing a series of states (51-55, 61-64) for initializing the communication system (10). A determination is made by the transceiver (24) whether a state change has occurred. A state change is identified and reported to a host processor (22) based on the program visibility select level.

Abstract: A symbol generator (804) generates a time-domain discrete multi-tone symbol (810). A magnitude comparator (812) compares the magnitude of the time-domain discrete multi-tone symbol (810) with a magnitude threshold. When the magnitude of the time-domain discrete multi-tone symbol (810) compares unfavorably to the magnitude threshold, a magnitude adjusting symbol (816) is added to the time-domain discrete multi-tone symbol (810) such that the magnitude of the time-domain discrete multi-tone symbol (810) is reduced, thereby reducing the peak-to-average requirements (PAR).

Abstract: A flexible asymmetrical digital subscriber line (ADSL) transmitter is able to operate simultaneously with integrated services digital network (ISDN) terminal equipment (TE) using a common telephone line (18). The ADSL transmitter changes the frequency content of a frequency-encoded ADSL signal (104) so that its frequency content does not overlap the frequency content of the ISDN TE signal. A corresponding ADSL receiver located within a central office (CO) adapts to the changed frequency content, allowing the ADSL signal to be transmitted over the telephone line without substantial loss of signal integrity. In one embodiment, an ADSL transmitter (100) converts ADSL symbols making up the frequency-encoded ADSL signal (104) into a corresponding time domain signal. The transmitter (100) then interpolates the time domain signal and high pass filters the interpolated signal. This high pass filtered signal is then converted to analog form, bandpass filtered, and driven onto the telephone line (18).

Abstract: An ADSL receiver (200) receives an upstream modified ADSL signal and an ISDN signal from a remote terminal (32) on a twisted-pair copper wire (18). An ADSL transmitter (100) of the remote terminal (32) transmits the ADSL signal in a frequency range above an ISDN frequency range so that the ADSL signal does not overlap the frequency range of the ISDN signal. In one embodiment, the ADSL receiver (200) includes a band pass filter (201), an analog-to-digital converter (203), a decimator (205), a fast Fourier transform (210), and a digital signal processor (212). The decimator (205) converts the ADSL signal back to base band, thus allowing an ADSL signal source to simultaneously utilize the telephone line with an ISDN signal source, without significantly reducing ADSL throughput.

Abstract: A solar collector includes a collector body having a substantially curved collector surface. A reflective device projects from the collector body and reflects incident solar energy to the collector surface. The collector body is substantially conical and the reflective device is secured to and projects externally from the conical collector body. The reflective device has a curved surface which extends along an arc of a circle and which overlies the collector surface for reflecting incident solar radiation over a portion of the collector surface.

Abstract: A solenoid actuator including a coil of electrically conductive wire having a central opening, a yoke of magnetic material permanently surrounding the coil, and a stationary armature permanently secured to the yoke and projecting from the yoke into the central opening in the coil. A core tube of non-magnetic material is removably retained within the central opening in the coil, the core tube having a closed end engaging the stationary armature and the core tube being separable from the coil-yoke-armature assembly. A movable armature within the core tube is slidable toward and away from the stationary armature. A stationary armature extension of magnetic material surrounds the exterior of the core tube, the extensions being an element independent of the stationary armature. The extension may be an annular element, coaxial with the core tube, which engages the stationary armature. The extension may be a ring having a wall of uniform or non-uniform thickness along its length.

Abstract: A valve including a pilot valve body having an inlet port, an outlet port, and an orifice between the ports surrounded by a valve seat. A valve member is movable into and out of engagement with the valve seat to close and open the valve, respectively. The valve member can be oscillated to permit a reduced rate of flow through the valve. The valve member may be carried by the armature of an electrical solenoid; when the solenoid is energized by full wave AC power, the valve is held open in a stable condition, and when the solenoid is energized by half wave AC power, the valve member oscillates. The valve is used as the pilot valve of a main valve, wherein when the valve member is oscillated to permit reduced rate flow through the pilot valve, the main valve remains closed.