418 results about "Signal band" patented technology

Apparatus, method, logic arrangement and storage medium are provided for increasing the sensitivity in the detection of optical coherence tomography and low coherence interferometry (“LCI”) signals by detecting a parallel set of spectral bands, each band being a unique combination of optical frequencies. The LCI broad bandwidth source can be split into N spectral bands. The N spectral bands can be individually detected and processed to provide an increase in the signal-to-noise ratio by a factor of N. Each spectral band may be detected by a separate photo detector and amplified. For each spectral band, the signal can be band p3 filtered around the signal band by analog electronics and digitized, or, alternatively, the signal may be digitized and band pass filtered in software. As a consequence, the shot noise contribution to the signal is likely reduced by a factor equal to the number of spectral bands, while the signal amplitude can remain the same. The reduction of the shot noise increases the dynamic range and sensitivity of the system.

Apparatus and method for increasing the sensitivity in the detection of optical coherence tomography and low coherence interferometry (“LCI”) signals by detecting a parallel set of spectral bands, each band being a unique combination of optical frequencies. The LCI broad bandwidth source is split into N spectral bands. The N spectral bands are individually detected and processed to provide an increase in the signal-to-noise ratio by a factor of N. Each spectral band is detected by a separate photo detector and amplified. For each spectral band the signal is band pass filtered around the signal band by analog electronics and digitized, or, alternatively, the signal may be digitized and band pass filtered in software. As a consequence, the shot noise contribution to the signal is reduced by a factor equal to the number of spectral bands. The signal remains the same. The reduction of the shot noise increases the dynamic range and sensitivity of the system.

An analog-to-digital converter system [50D] processing an input signal, g, which can be either a discrete-time or a continuous-time signal. A first quantizer [154] generates a first digital signal, d0(k), representing the sum of the input signal, g, and a dithering signal, y0. A digital-to-analog converter [156] generates an analog feedback signal, alpha, representing accurately the first digital signal, d0(k). The DAC [156] may be linearized by the use of mismatch-shaping techniques. A filter [158] generates the dithering signal, y0, by selectively amplifying in the signal band the residue signal, r0, defined as the difference of the input signal, g, and the analog feedback signal, alpha. Optional signal paths [166][168] are used to minimize the closed-loop signal transfer function from g to y0, which ideally will be zero. An analog compensation signal, m0, which is described by a well-controlled relationship to the residue signal, r0, is extracted from the filter [158]. Ideally, the closed-loop signal transfer function from g to m0 will be zero, or at least small in the signal band. A second quantizer [160] converts the analog compensation signal, m0, into a second digital signal, dm0(k). The two digital signals, d0(k) and dm0(k), are filtered individually and then added to form the overall output signal, dg(k). The second digital filter [164] has a low signal-band gain, which implies that the sensitivity to signal-band errors caused by the second quantizer [160] will be low. The output signal, dg(k), is a highly-accurate high-resolution representation of the input signal, g. Circuit imperfections, such as mismatch, gain errors, and nonlinearities, will cause only noise-like errors having a very low spectral power density in the signal band.The invention facilitates the implementation of uncalibrated highly-linear high-resolution wide-bandwidth A/D converters [50D], e.g., for use in digital communication systems, such as xDSL modems and other demanding consumer-market products for which low cost is of the essence.

A conventional power amplifying device has a problem that when a signal band is widened, sampling frequency for distortion detection is increased and an FFT calculation amount of a distortion compensation unit is increased, which increase a circuit size and power consumption. The present invention provides a non-linear distortion detection method and a distortion compensation amplifying device capable of suppressing increase of the circuit size and the power consumption even if the signal band is widened. A signal obtained by feeding back an output of a power amplifier is sampled by an A/D converter. An equalizer of a distortion detection unit uses an input signal d(n) of a predistorter as a reference symbol to detect an equalization error e(n) of the orthogonal demodulation signal u(n). An absolute value averaging unit outputs an absolute value of the equalization error e(n) which has been temporally averaged to E(n) as a distortion value to a control unit. According to the distortion value, the control unit adaptively controls the predistorter to perform distortion compensation.

A compact via transmission line for a printed circuit board having preferred characteristic impedance and capable of miniaturizing the printed circuit board including a multilayer printed circuit board, and extending the frequency range of a via transmission line mounted on the printed circuit board, and a design method of the same. The transmission line has a central conductor forming an inner conductor layer boundary make up a signal via hole, a plurality of via holes arranged around the central conductor form an outer conductor layer boundary, and a plurality of conductor plates formed of a printed circuit board conductor layer, is further provided with a constitutive parameter adjustment clearance hole between the inner and outer conductor layer boundaries of the compact via transmission line, and electrically isolates to prevent cross-talk of a signal propagating through a signal via hole with other signals in a high-frequency signal band.

An integrated patch antenna is disclosed. The integrated patch antenna receives at least a first and second band of signals. The integrated patch antenna includes a bottom metallization and first and second upper metallizations disposed about a dielectric material to receive the first and second signal bands. The first and second signal bands may be, for example, a satellite digital audio radio systems (SDARS) band and a global positioning system (GPS) band.

There is disclosed an encoding device capable of appropriately adjusting the dynamic range of spectrum inserted according to the technique for replacing a spectrum of a certain band with a spectrum of another band. The device includes a spectrum modification unit (112) which modifies a first spectrum S1(k) of the band 0≦k<FL in various ways to change the dynamic range so that a way of modification for obtaining an appropriate dynamic range is checked. The information concerning the modification is encoded and given to a multiplexing unit (115). By using a second spectrum S2(k) having a valid signal band 0≦k.

An optic Distributed Antenna System includes a Head End (HE) configured to adjust a first signal for a first carrier at a first band to a first level, to adjust a second signal having at least a carrier different from the first carrier or a band different from the first band to a second level, to combine the first and second signals, to perform Electronic/Optic conversion on the combined signal, and to optic-distribute and send the combined optic signal, and a plurality of Remote Units (RUs) each connected to the HE over a corresponding single optic line, wherein each of the RUs is configured to perform Optic/Electronic conversion on the combined optic signal, to adjust the converted signal for each signal band, to perform high-power amplification on the adjusted signals, to multiplex the amplified signals, and to transmit the multiplexed signal to a Mobile station via at least one antenna.

A radio-frequency (RF) apparatus includes front-end circuitry. The front-end circuitry includes a filter circuitry and an impedance matching circuitry. The filter circuitry has a differential output that has an output impedance. The filter circuitry filters signals outside a signal band of interest. The impedance matching network has a differential input coupled to the output of the filter circuitry. The impedance matching network also has a differential output coupled to a signal processing circuitry. The signal processing circuitry has an input impedance. The impedance matching network matches the input impedance of the signal processing circuitry to the output impedance of the filter circuitry.

Disclosed is an electronic device including a first antenna element configured selectively to receive signals of a first frequency band and a second frequency band or of the first frequency band and a third frequency band, a second antenna element configured to receive a signal of the third frequency band, a transceiver configured to be electrically connected with the first antenna element and the second antenna element, and a processor configured to be electrically connected with the transceiver. The electronic device performs carrier aggregation using the second frequency band and the third frequency band.

A system and method for post filtering signal peak reduction adapted for use in a communication system incorporating a source of a communication signal band limited in a manner corresponding to a spectral band to which the communication system is limited. A first signal path receives as an input the band limited communication signal. A second parallel signal path includes a peak reduction calculation unit for calculating a peak reduction correction signal and a filter providing a filtering operation on the peak reduction correction signal corresponding to the spectral band to which the communication system is limited. The filtered peak reduction correction signal and delayed input signal are combined to provide peak adjusted output signals without violating the band limits of the communication signal or the modulation scheme of the communication signal.

A surface emitting semiconductor laser (10) is shown having a semiconductor lasing structure having an active layer (22), opposed cladding layers contiguous to said active layer, a substrate (17), and electrodes (12,14) by which current can be injected into the semiconductor lasing structure. Also included is a second or higher order distributed diffraction grating (24) having periodically alternating elements, each of the elements being characterized as being either a high gain element (26) or a low gain element (28). Each of the elements has a length, the length of the high gain element and the length of the low gain element together defining a grating period, where the grating period is in the range required to produce an optical signal in the optical telecommunications signal band. The total length of the high gain elements is no more than the total the lengths of the low gain elements. A single laser structure may be provided or an array of side by side laser structures on a common substrate is also provided. In a further aspect a method of testing laser structures on wafer is provided.

A tuner and demodulator performing image rejection in an analog cable television system. Various embodiments disclose a tuner including an analog RF section to generate a complex intermediate frequency digital signal, an image rejection module configured to perform image rejection on the complex intermediate frequency digital signal to generate an enhanced image rejection signal, a signal channel select filter configured to perform digital on-chip filtering on the enhanced image rejection signal to generate a filtered signal, and a demodulator configured to demodulate the filtered signal to generate digital output signals. In some embodiments, the tuner is substantially or fully monolithic. In some embodiments, the tuner performs image rejection by applying an algorithm to estimate a signal correlation between the signal band and the image band of the complex intermediate frequency digital signal, and providing adaptive filtering to reduce signal leakage and image leakage.

A communication system comprising a network having a legacy band and an extendable frequency band, a head end, and a user end, wherein said head end processes and splits source data into multiple signals and transmits said multiple signals over multiple physical channels over said extendable frequency band, and wherein said user end containing multiple receivers and a data reconstructor receives said multiple signals and recovers said source data. Another embodiment includes a communication system comprising a network having a legacy band and an extendable frequency band, a head end; and a user end, wherein said user end processes and splits source data into multiple signals and transmits said multiple signals over multiple physical channels over said extendable frequency band and wherein said head end receives said multiple signals and recovers said source data. Other embodiments include methods of communication over a network having a legacy band and an extendable frequency band.

A bandpass filter bandpass-filters an inputted signal X to pass therethrough a partial band of a band of the inputted signal X, and a level correlated white noise generator circuit generates a white noise signal having a level changing according to a level of the inputted signal and correlated to the inputted signal. A signal processing circuit executes a signal processing that includes a predetermined bandpass filtering processing, an echo adding processing, and a level adjustment processing, and that multiplies the inputted white, noise signal by a predetermined transfer function, and outputs a processed white noise signal to an adder. The adder adds up the white noise signal from the signal processing circuit and the inputted signal X, and outputs a band-extended signal having an addition result, as an outputted signal.