Abstract: A Viterbi trellis processing technique in which soft decisions and hard decisions are derived from a received signal and the soft decisions are enhanced by being modified using the hard decisions. A log likelihood ratio for a bit of the received signal can be derived by grouping candidate metrics associated with the decision that the bit has a first state, grouping candidate metrics associated with the decision that the bit has a second state, applying respective functions to the groups and calculating the difference of the function values.

Abstract: A wireless receiver uses a joint detection Viterbi (JDV) algorithm to demodulate a signal that has a desired signal component and an interference signal component. The desired signal component includes a training sequence and at least one data field. The training sequence and a corresponding portion of the interference signal component is demodulated using the JDV algorithm to evaluate possible transmitted training sequences and interference signal sequences, and channel estimations for the desired signal component and the interference signal component are generated. The at least one data field is demodulated according to the JDV algorithm using the channel estimations as initial channel estimates for the JDV algorithm.

Abstract: A communications signal is received through a propagation channel, down-converted in frequency and then converted into a digital signal. The samples of the digital signal are processed to estimate the information conveyed by the communications signal. The estimated information is then used with knowledge about the propagation channel to model the samples of the digital signal. The modeled samples are compared with actual samples of the digital signal to deduce phase errors in the digital signal. The phase errors are then used to deduce a frequency error in the digital signal that can be used to correct the samples of the digital signal and to correct the down-conversion process.

Abstract: A scheme for deducing a DC offset in a received signal burst acquired through a particular channel, wherein the received signal burst corresponds to a transmitted signal burst. An impulse response estimate of the channel is used to model how a known or recovered part of the transmitted burst would have been affected by passage through said channel in place of the corresponding part of the transmitted signal burst. The modelled part of the transmitted burst is then compared with the corresponding part of the received signal burst to deduce a DC offset present in the received signal burst.

Abstract: A telecommunications network participant, comprising means for digitising, as a series of samples, a received signal containing a succession of symbols, means for measuring time misalignment between the symbols and the samples and means for applying a fractional delay to the positions of the samples to reduce the misalignment.

Abstract: A method of forming a multijunction solar cell includes providing a substrate, forming a first subcell by depositing a nucleation layer over the substrate and a buffer layer including gallium arsenide (GaAs) over the nucleation layer, forming a middle second subcell having a heterojunction base and emitter disposed over the first subcell and forming first and second tunnel junction layers between the first and second subcells. The first tunnel junction layer includes GaAs over the first subcell and the second tunnel junction layer includes aluminum gallium arsenide (AlGaAs) over the first tunnel junction layer. The method further includes forming a third subcell having a homojunction base and emitter disposed over the middle subcell.

Abstract: A wireless receiver uses a joint detection Viterbi (JDV) algorithm to demodulate a signal that has a desired signal component and an interference signal component. The desired signal component includes a training sequence and at least one data field. The training sequence and a corresponding portion of the interference signal component is demodulated using the JDV algorithm to evaluate possible transmitted training sequences and interference signal sequences, and channel estimations for the desired signal component and the interference signal component are generated. The at least one data field is demodulated according to the JDV algorithm using the channel estimations as initial channel estimates for the JDV algorithm.

Abstract: A receiver adaptively selects between a joint detection Viterbi demodulator and a second Viterbi demodulator to demodulate a received signal based on at least one characteristic of the received signal. The joint detection Viterbi demodulator jointly demodulates a desired signal component and an interference signal component of the received signal, and the second Viterbi demodulator demodulates the desired signal component without demodulating the interference signal component.

Abstract: A method and a multijunction solar device having a high band gap heterojunction middle solar cell are disclosed. In one embodiment, a triple-junction solar device includes bottom, middle, and top cells. The bottom cell has a germanium (Ge) substrate and a buffer layer, wherein the buffer layer is disposed over the Ge substrate. The middle cell contains a heterojunction structure, which further includes an emitter layer and a base layer that are disposed over the bottom cell. The top cell contains an emitter layer and a base layer disposed over the middle cell.

Abstract: A Viterbi trellis processing technique in which soft decisions and hard decisions are derived from a received signal and the soft decisions are enhanced by being modified using the hard decisions. A log likelihood ratio for a bit of the received signal can be derived by grouping candidate metrics associated with the decision that the bit has a first state, grouping candidate metrics associated with the decision that the bit has a second state, applying respective functions to the groups and calculating the difference of the function values.

Abstract: A scheme for deducing a DC offset in a received signal burst acquired through a particular channel, wherein the received signal burst corresponds to a transmitted signal burst. An impulse response estimate of the channel is used to model how a known or recovered part of the transmitted burst would have been affected by passage through said channel in place of the corresponding part of the transmitted signal burst. The modeled part of the transmitted burst is then compared with the corresponding part of the received signal burst to deduce a DC offset present in the received signal burst.

Abstract: A communications signal is received through a propagation channel, down-converted in frequency and then converted into a digital signal. The samples of the digital signal are processed to estimate the information conveyed by the communications signal. The estimated information is then used with knowledge about the propagation channel to model the samples of the digital signal. The modeled samples are compared with actual samples of the digital signal to deduce phase errors in the digital signal. The phase errors are then used to deduce a frequency error in the digital signal that can be used to correct the samples of the digital signal and to correct the down-conversion process.

Abstract: A telecommunications network participant, comprising means for digitising, as a series of samples, a received signal containing a succession of symbols, means for measuring time misalignment between the symbols and the samples and means for applying a fractional delay to the positions of the samples to reduce the misalignment.

Abstract: A method and a multijunction solar device having a high band gap heterojunction middle solar cell are disclosed. In one embodiment, a triple-junction solar device includes bottom, middle, and top cells. The bottom cell has a germanium (Ge) substrate and a buffer layer, wherein the buffer layer is disposed over the Ge substrate. The middle cell contains a heterojunction structure, which further includes an emitter layer and a base layer that are disposed over the bottom cell. The top cell contains an emitter layer and a base layer disposed over the middle cell.

Abstract: In a preferred embodiment, an indium gallium phosphide (InGaP) nucleation layer is disposed between the germanium (Ge) substrate and the overlying dual-junction epilayers for controlling the diffusion depth of the n-doping in the germanium junction. Specifically, by acting as a diffusion barrier to arsenic (As) contained in the overlying epilayers and as a source of n-type dopant for forming the germanium junction, the nucleation layer enables the growth time and temperature in the epilayer device process to be minimized without compromising the integrity of the dual-junction epilayer structure. This in turn allows the arsenic diffusion into the germanium substrate to be optimally controlled by varying the thickness of the nucleation layer. An active germanium junction formed in accordance with the present invention has a typical diffused junction depth that is ? to ½ of that achievable in prior art devices.

Abstract: A method and a multijunction solar device having a high band gap heterojunction middle solar cell are disclosed. In one embodiment, a triple-junction solar device includes bottom, middle, and top cells. The bottom cell has a germanium (Ge) substrate and a buffer layer, wherein the buffer layer is disposed over the Ge substrate. The middle cell contains a heterojunction structure, which further includes an emitter layer and a base layer that are disposed over the bottom cell. The top cell contains an emitter layer and a base layer disposed over the middle cell.

Abstract: A method and a multijunction solar device having a high band gap heterojunction middle solar cell are disclosed. In one embodiment, a triple-junction solar device includes bottom, middle, and top cells. The bottom cell has a germanium (Ge) substrate and a buffer layer, wherein the buffer layer is disposed over the Ge substrate. The middle cell contains a heterojunction structure, which further includes an emitter layer and a base layer that are disposed over the bottom cell. The top cell contains an emitter layer and a base layer disposed over the middle cell.