1147 results about "Non coherent" patented technology

Methods and apparatus for efficient two-stage paging wireless communications systems are described. Wireless terminals are assigned to paging groups. A few first paging message information bits are modulated (using non-coherent modulation) into a first paging signal and communicated from a base station to wireless terminals. WTs wake-up, receive the first paging signal and quickly ascertain whether its paging group should expect a second paging signal, if so, the WT is operated to receive the second paging signal; otherwise, the WT goes back to sleep conserving power. The base station modulates (using coherent modulation) a number of second message information bits into a second paging signal and transmits the signal to WTs. From the information in first and second paging signals, a WT can determine that it is the paged WT and process the paging instructions. The intended paged WT can transmit an acknowledgement signal on a dedicated uplink resource.

A high power light source is provided. The light source includes one or more diodes that may produce relatively coherent light of a desired intensity. The diodes may be pulsed to provide light as desired. The light projected by the diodes passes through a combiner, which combines the light from the different diodes and passes the combined light to an incoherence apparatus. The incoherence apparatus may include a rotating surface relief phase device such as an optical hologram, a computer generated hologram, or a diffractive optical element with random phase modulation. The incoherence apparatus may include a rotating fiber conduit comprising a plurality of multifiber cores. The incoherence apparatus renders the combined light incoherent and passes it to an illuminator apparatus that focuses the incoherent combined light onto an image plane.

The present invention discloses a low-cost light source for optical transmission systems and optical networks based on wavelength-division multiplexing (WDM) technology. A light source in accordance with the present invention is implemented by externally injecting a narrow-band incoherent light into a Fabry-Perot laser diode (F-P LD). After injection of narrow-band incoherent light, the output of F-P LD becomes wavelength-selective rather than multi-mode and the output wavelength of F-P LD coincide with the peak wavelength of the injected incoherent light. Multi-channel WDM light sources according to the present invention can be implemented using a single broadband incoherent light source and plurality of F-P LDs. An optical transmission system for upstream signal transmission in an passive optical network using the light source according the present invention is also disclosed.

The present invention centers upon uplink communication protocols for use primarily with orthogonal frequency division multiple access (OFDMA) communication systems. Aspects of the invention relate to narrow band frequency division multiplexed (NBFDM) modulation protocols primarily for uplink usage in asymmetric OFDMA communication systems. In particular, NBFDM uplinks that use quadrature multiplexed continuous phase modulation are detailed and noncoherent detection schemes are developed to process the uplink channel signals without the need to transmit uplink phase reference signals. Other aspects of the invention relate to burst mode uplink communications in OFDMA systems such as those involving opportunistic beamforming.

The invention relates notably to a method for modulating information symbols to be transmitted in a CDMA communication network by using a non-orthogonal modulation code comprising M spreading sequences (s_m 1≦m≦M), each comprising in N chips (s_m,n 1≦n≦N), the M spreading sequences having the same energy.

According to the invention, the amplitude of the chips take a plurality of values the number M of spreading sequences is higher than the number of chips N per spreading sequence.

The present invention provides a fluorescence detection and photodynamic therapy apparatus including: a combined light source unit 10 including a plurality of coherent and non-coherent light sources 11, 12 and 13 configured to irradiate light onto a to-be-observed object while performing continuous illumination; an optical imaging unit 20 configured to form an image of the to-be-observed object 70 and project the image to an image processing/controlling system 34; a multispectral imaging unit 30 including a one-chip multispectral sensor and the image processing/controlling system 34; a blocking filter 40 installed between the to-be-observed object 70 and the one-chip multispectral sensor 32, the blocking filter being configured to block some light reflected off from the to-be-observed object 70 while allowing some light and fluorescent light to pass therethrough; a computer system 50 configured to process, analyze, reproduce and store the image acquired from the multispectral imaging unit 30, and transfer the image to a display device 60 and control the overall operation of all the related elements; and the display device 60 configured to display a processing result of the image by the computer system 50.

A real-time radar surveillance system comprises at least one land-based non-coherent radar sensor apparatus adapted for detecting maneuvering targets and targets of small or low radar cross-section. The radar sensor apparatus includes a marine radar device, a digitizer connected to the marine radar device for receiving therefrom samples of radar video echo signals, and computer programmed to implement a software-configurable radar processor generating target data including detection data and track data, the computer being connectable to a computer network including a database. The processor is figured to transmit at least a portion of the target data over the network to the database, the database being accessible via the network by at least one user application that receives target data from the database, the user application providing a user interface for at least one user of the system.

Quick frequency tracking (QFT), quick time tracking (QTT), and non-causal pilot filtering (NCP) are used to detect sporadically transmitted signaling, e.g., paging indicators. For QFT, multiple hypothesized frequency errors are applied to an input signal to obtain multiple rotated signals. The energies of the rotated signals are computed. The hypothesized frequency error with the largest energy is provided as a frequency error estimate. For QTT, coherent accumulation is performed on the input signal for a first set of time offsets, e.g., early, on-time, and late. Interpolation, energy computation, and non-coherent accumulation are then performed to obtain a timing error estimate with higher time resolution. For NCP, pilot symbols are filtered with a non-causal filter to obtain pilot estimates for one antenna for non-STTD and for two antennas for STTD. The frequency and timing error estimates and the pilot estimates are used to detect the signaling.

A system for increasing the depth of field and decreasing the wavelength sensitivity of an incoherent optical system incorporates a special purpose optical mask into the incoherent system. The optical mask has been designed to cause the optical transfer function to remain essentially constant within some range from the in-focus position. Signal processing of the resulting intermediate image undoes the optical transfer modifying effects of the mask, resulting in an in-focus image over an increased depth of field. Generally the mask is placed at or near an aperture stop or image of the aperture stop of the optical system. Preferably, the mask modifies only phase and not amplitude of light, though amplitude may be changed by associated filters or the like. The mask may be used to increase the useful range of passive ranging systems.

The present invention is a method and apparatus for compressing and decompressing data. In particular, the present invention provides for (de-)compressing naturalistic color-image and moving-image data, including high-precision and high-definition formats, with zero information loss, one-sample latency and in faster than real time on common computing platforms, resulting in doubled transmission, storage, and playback speed and doubled transmission bandwidth and storage capacity, and hence in doubled throughput for non-CPU-bound image-editing tasks in comparison with uncompressed formats. The present invention uses a nearly symmetrical compression-decompression scheme that provides temporal, spatial, and spectral compression, using a reversible condensing/decondensing filter, context reducer, and encoder/decoder. In the preferred embodiment of the invention, the compression filter is implemented as a cascade of quasilinear feedforward filters, with temporal, multidimensional spatial, and spectral stages, where appropriate, in that order, whose support consists of adjacent causal samples of the respective image. The decompressor cascades quasilinear feedback inverse filters in the reverse order. The filters can be implemented with mere integer addition, subtraction, and either one-dimensional table lookup or constant multiplication and binary shifting, depending on the computing environment Tables permit the data precision to be constrained throughout to that of the image samples. The encoder uses a table of prefix codes roughly inversely proportional in length to their probability, while the decoder uses chunked decode tables for accelerated lookup. In the fastest and simplest mode, the code tables are context-independent. For greater power, at the cost of a reduction in speed, the code tables are based on the temporal, multidimensional spatial, and spectral adjacent causal residue samples, where contexts with similar probability distributions are incoherently collapsed by a context reducer using one-dimensional lookup tables followed by implicitly multidimensional lookup tables, to minimize the overall table size. The invention's minimal resource requirements makes it ideal for implementation in either hardware or software.

An autocorrelator apparatus and method for economically measuring physical properties of an object where the measurement path is at least semi-translucent to light, such as thicknesses in multilayered optical structures, group index of refraction, and distance to a surface. The apparatus includes a non-coherent light fiber interferometer and an optional coherent light fiber interferometer in association so as to share PZT fiber modulators. Thickness and boundary extent measurements can be made, for example, of solids, liquids, liquids moving along a horizontal plane, or liquids flowing down a plane.

The present application discloses an apparatus and a method for synchronizing the activation of a light source with the position of a hand piece on a surface and for providing a substantially homogenous exposure of a surface to light irradiation. The apparatus includes a light source, a handpiece for delivering light pulses to the irradiated surface, and a beam delivery system for delivering light from the light source to the handpiece. The handpiece, which is moved along the surface by an operator, includes a sensor for sensing the distance traversed by the handpiece on the surface. The sensor sends signals to a signal processing unit which calculates the distance traversed by the handpiece on the surface and controls the activation of the light source either by automatically activating the light source or by providing the operator with a signal indicating that the light source should be pulsed. The handpiece can also include a device for cooling the irradiated surface and for marking the irradiated part of the surface with a visible marker. The handpiece may be constructed to be movable along a surface in a predetermined orientation relative to the handpiece. Alternatively, the handpiece may be freely movable along the surface in any desired orientation. The light source can be a pulsed laser, a continuous wave laser or a non-coherent light source.

Embodiments comprise a device that can efficiently produce a highly resolved intensity profile that can be easily switched to various specific configurations with binary word strings defining output intensities that after summation will be combined to form a single colors intensity depth. Arraying these devices allows an image line of single color pixels to be efficiently produced without gross scintillation effects. The non-coherent output is desirable in this application as it reduces scintillation effects on the screen or final image.

Method for setup of parameter values in a RF power amplifier circuit arrangement (200), wherein the amplifier circuit arrangement (200) comprises a first (210) and a second (220) amplification branch and is operated in an out-phasing configuration for amplification of RF input signals with modulated amplitude and modulated phase and respective circuit arrangements are disclosed. According to a first aspect a re-optimization of the dead-time or conversely the duty-cycle, respectively, the phase of the output signal after the combiner can be kept linear with respect to the out-phasing angle. Further, according to a second aspect, additionally to introduction of an optimally chosen dead-time, a non-coherent combiner (Lx, Lx*) can reduce crowbar current and switching losses due the output capacitance (Cds). Furthermore, according to a third aspect the reactive compensation can, additionally or alternatively, be controlled by operating both amplification branches at different duty-cycles.

Disclosed herein is a computer-readable medium having stored thereon computer-executable instructions for providing phase-range data associated with a return pulse of a radar device and second phase-range data associated with a successive return pulse of the radar device. The computer-executable instructions are preferably also for comparing the phase-range data and the second phase-range data to obtain a difference, and for differentiating the difference. In some embodiments of the invention, the computer-executable instructions are preferably also for discriminating a target from clutter by using the differentiated difference to identify coordinates satisfying a velocity threshold associated with the clutter. Embodiments of the invention preferably enable phase-coherent operation of a non-coherent radar device by processing backscattered clutter return, and in some aspects, do so using clutter distributed in range as a reference. Related systems, methods, devices, and other embodiments are also disclosed herein.

A multiple integration hypothesis C/A code acquisition system resolves bit boundaries using parallel correlators providing magnitude hypotheses during acquisition to reduce losses over the 20 ms integration period to improve the performance and sensitivity of C/A code receivers to achieve low C/No performance using inexpensive, imprecise oscillators and long noncoherent dwell periods, well suited for in-building, multipath, and foliage attenuated GPS signaling applicable to E911 communications with several dB of additional improvement in receiver sensitivity due to the ability to detect bit synchronization during acquisition.

A method and an apparatus relating to an OFDM data communications system where the sub-carriers are modulated using differential quadrature phase-shift keying (DQPSK). The multi-carrier transmitted signal is directly generated by means of summation of pre-computed sample points. As part of the multi-carrier signal generation, a signal for the guard interval is established. In an acoustic application of this approach, direct radiation of the sub-carrier approach is facilitated. Symbol synchronization in the receiver is based on signal correlation with the missed sub-carrier. Separation of the sub-carriers in the receiver by means of correlation of the received signal and reference signals that are derived from a table of pre-computed values. Optimal non-coherent processing of the sub-carriers without any phase tracking procedures is achieved.

The invention relates to a method and an apparatus for agile RF spectrum monitoring in a radio system with dynamic frequency access. It provides a spectrum monitor based on non-coherent heterodyne detection that utilizes a DDS signal generator to digitally generate a reference signal at a variable reference frequency for mixing with an input RF signal received from an RF antenna, a pass-band filter and a log amplifier for obtaining energy estimates at a monitored transmission frequency corresponding to the reference frequency. A processor is provided for adaptively selecting sets of monitored transmission frequencies, for controlling the DDS signal generator, and for processing obtained spectral energy estimates to assess spectral usage data.