Abstract: A method for automatic initialization of an optical network is provided. A network management system (NMS) performs remote determination of span losses and sets the operating points of network components. The initialization method comprises remotely and automatically setting target gains of optical amplifiers and signal power levels at transmitters and receivers to required operating values. The methods for initialization of the optical network of the embodiments include gain excursion minimization (GEM) for individual channels passing through amplifiers and/or pre-emphasis of the optical link, where channel powers at the transmitters are biased to compensate for the effects of optical amplifiers gain ripple.

Abstract: A method includes taking backscattering light of a first wavelength in a first direction of a first transmission line and coupling the same so that the light may travel in a second direction of a second transmission line; taking a second wavelength in the first direction of the first transmission line and coupling the same so that the second wavelength may travel in the first direction of the second transmission line; taking backscattering light of the first wavelength in the second direction of the second transmission line and coupling the same so that the backscattering light may travel in the first direction of the first transmission line; taking the second wavelength in the second direction of the second transmission line and coupling the same so that the second wavelength may travel in the second direction of the first transmission line.

Abstract: Methods and apparatus for halting the data strobes transmitted over a source synchronous link to enable the data stored in the data capture flip-flops in a source synchronous receiver to be scanned out for subsequent analysis. This allows for the evaluation of the captured data without placing additional components in the functional data path and, therefore, without increasing the latency of the transmission. To provide optimal timing margins the data and data strobe paths are logically and electrically matched. This includes routing the data and data strobe signals in close proximity from the transmitter to the receiver, and through the same logical and physical elements in the transmitter and receiver. This insures that any injected link noise is experienced common-mode. In addition, the data strobe signal is preferably driven at one-half of the period of the data signal so that the data strobe and data signals experience logical state transitions at the same time and at the same frequency.

Abstract: In each node of an optical transmission system: an optical preamplifier has an ALC function for maintaining an optical output level constant and an AGC function for maintaining the gain constant; the operational mode of the optical preamplifier is changed from an ALC mode to an AGC mode after the gain is set in the ALC mode; an optical postamplifier has an AGC function; an optical switch unit performs an optical crossconnect operation; and a thru-light-shutoff control unit makes a switch setting so as to shut off pass-through light in the optical switch unit and stop transmission of an optical signal having an unstable level to a next stage when the optical preamplifier operates in the ALC mode, and clears the switch setting when the operational mode of the optical preamplifier is changed to the AGC mode.

Abstract: A system for generating (PN) spread signals is provided. The system includes a first clock synchronized with a second clock and at least three first pseudo-noise (PN) component code generators coupled to the first clock. A logic combiner is coupled to the PN component code generators and is adapted to generate a composite PN code. Both clocks are coupled to respective N-bit and M-bit counters.

Abstract: A light demultiplexer in which a signal and a noise in each channel may be distinctly separated is provided. The light demultiplexer comprises a light-receiving element array for receiving light beams demultiplexed every wavelength from a wavelength multiplexed light beam and arranged in a straight line. The light-receiving element array includes a plurality of light-receiving elements for monitoring signals, and a plurality of light-receiving elements for monitoring noises. The light-receiving elements for monitoring signals and the light-receiving elements for monitoring noise are alternately arrayed in a straight line the direction thereof is the same as that of the arrangement of the demultiplexed light beams.

Abstract: The invention relates to a method for communicating multimedia data between electronic devices by means of IR ray, which comprises the steps of converting data to be transmitted into a document by a document processing program installed in an electronic device for transmission, appending a filename extension thereto for classifying the document, transmitting the document through an IR transceiving control signal by an IR transceiver of the said electronic device, receiving the control signal as an indicative of the transmitted document by another electronic device for receiving, and identifying and processing the received document based on the filename extension thereof so as to create an identifiable data.

Abstract: The invention relates to a method of setting up a call between a central module (33) and a remote module (37) of the type comprising at least one first transmission channel and one second transmission channel according to distinct primary and secondary bit rates respectively. According to the invention, the method comprises the steps setting up a call by default on the first channel; listening and searching for a signal indicating a secondary bit-rate requirement, assuming a detection of the signal indicating a secondary bit-rate requirement, a phase for the switching of a bit rate from the first primary bit-rate transmission channel to the secondary bit-rate transmission channel, associated with a step for the masking, during a predetermined masking period, of an acknowledgement signal sent during the default setting-up phase. The invention also concerns a corresponding switching method, transmission network section and transmission network.

Abstract: This invention relates to parallel architecture digital filter and signal receiver with spectrum spreading using such a filter, the filter may have p shift registers (Rp, Ri) with means for calculating a weighted sum of stored samples in the registers, p weighted sums (Skp, Ski) may be obtained and recombined with number p being, for example, equal to 2.

Abstract: A blind adaptive filtering method for receivers of communication systems without need of training sequences, and whose performance is close to that of the non-blind linear minimum mean square error (LMMSE) receivers with training sequences required in practical environments of finite signal-to-noise (SNR) and data length. This algorithm is an iterative batch processing algorithm using cumulant based inverse filter criteria with super-exponential convergence rate and low computational load. The receivers to which the presented algorithm can be applied are (but not limited to) equalizers of conventional time division multiple access (TDMA) digital communication systems, and smart antennas based on space-time processing for wireless communication systems.

Abstract: A system for decoding an electrical input signal includes a filter that impresses a variable gain on the portion of input signal to deemphasize a spectral region of the input signal. The variable gain is set as a function of a variable gain control signal. A frequency detector generates the variable gain control signal in accordance with a frequency value wherein approximately one-half of the energy of the input signal is below the frequency value.

Abstract: An optical communication system using a high altitude tethered balloon 10 that operates above most clouds and atmospheric turbulence. An optical communication system includes a balloon 10 with an optical communication payload 30, a fiber optic cable attached to the tether 12, an automated winch system 14, and a ground station 28. The balloon 10 is designed for sustained flight at, and recovery from, high altitude using the automated winch system 14. An acquisition, tracking and pointing (ATP) system 22 enables a balloon-based optical transceiver 24 to maintain line-of-sight optical communications with an overhead satellite 34. The optical link between the satellite 34 and the balloon 10 is an open channel. Data is transmitted to the ground station 28 from the balloon 10 through the secure fiber optic closed channel attached to the tether 12.

Abstract: Circuitry for transmitting signals through a transformer has an output transistor and circuitry which provides a controlled current to and from the output transistor's gate, so as to charge and discharge the gate's parasitic capacitance and increase and decrease the transistor's output current in a controlled manner. Feedback can be used to sense an output signal created by the transistor and turn off current to or from the transistor's gate when the output signal has reached a desired level. The output signal can be the voltage differential produced across an output transformer, and, where the output transformer is center-tapped, it can be the voltage differential across both halves of the center tapped winding.

Abstract: The present invention is a system, mobile device and process. In a system, including a plurality of transmitters which transmit from at least one of the transmitters first and second complex sequences respectively from two spatially diverse antennas of the at least one transmitter to a mobile device, a method at the mobile device in accordance with the invention includes demodulating the first and second complex sequences to produce demodulated complex first and second sequences; detecting the demodulated first and second complex sequences to produce detected complex first and second sequences by multiplying respectively the demodulated first and second complex sequences with complex conjugates thereof; averaging a function of the complex detected first and second sequences to produce an averaged function; and processing the averaged function to detect a time, relative to a system time reference, of at least one peak therein resultant from the transmission of the first and second complex sequences.

Abstract: A phase detection apparatus is described for use in a phase lock loop (PLL). The apparatus has a first input for a reference signal, a second input for a loop feedback signal and an output for the phase difference signal. Two D-type flips flops are provided, the first being clocked with the reference signal and the second with the loop feedback signal. The output of the second flip-flop is delayed relative to the first flip-flop, thereby effecting minimal overlap, when using the phase detection apparatus in a fractional- N phase lock loop, of the interpolator activity with that of the charge pump.

Abstract: Methods of and apparatus for digitally controlling, with sub-sample resolution, the relative timing of the magnitude and phase paths in a polar modulator. The timing resolution is limited by the dynamic range of the system as opposed to the sample rate. The methods and apparatus of the invention use a digital filter to approximate a sub-sample time delay. Various techniques for approximating a sub-sample time delay using digital signal processing may be used to achieve the approximation. Ideally, the filter will have an all-pass magnitude response and a linear phase response. In practice, the magnitude may be low-pass and the phase may not be perfectly linear. Such deviation from the ideal response will introduce some distortion. However, this distortion may be acceptably small depending on the particular signal being processed.

Abstract: A system and method for transmitting data over a channel, in which the data are categorized in at least two different categories. For example, the data are categorized according to the effect on perceived degradation on the data when error mitigation is performed on the data. Corrupted data of the first category are replaced using a first replacement method, such as retransmission and forward error correction. The corrupted data of the second category are replaced using a second replacement method different from the first replacement method, e.g., error mitigation or interpolation.

Abstract: A network-based system and method for providing anonymous voice communications using the telephone network and data communications links under the direction of a Call Broker and associated network elements. A user (the call initiator) present in a text chat room session establishes a data connection to Call Broker and, after qualifying for access (e.g., using credit card information) and providing a callback number, receives voice session information and participant access codes for each desired participant in a voice call. The initiator causes session information and participant codes to be passed to one or more selected chat participants in the current text chat room. When a selected participant uses the received session information, and enters the received participant code and a callback number, the Call Broker in cooperation with a Network Adjunct Processor (NAP) completes voice links to the initiator and the selected participant(s).

Abstract: A communication system (20) uses TDMA techniques to distinguish intended recipients of a communication signal (26) from one another, and direct sequence spread spectrum (DSSS) techniques to encode and distinguish diverse parallel substreams (70, 74) of each user's data stream. Parallel unspread substreams (70) are spread using cyclic variations of a common spreading code (38). In one embodiment, the common spreading code (38) is chosen for low aperiodic autocorrelation sidelobes and a substantially flat spectral analysis. In another embodiment the common spreading code (38) is chosen for low periodic autocorrelation sidelobes and a substantially flat spectral analysis. In one embodiment, the use of cyclic variations of the spreading code (38) along with a cyclic prefix (114) enables the mathematical communicative matrix multiplication property, thereby permitting equalization for multipath to occur following or in conjunction with despreading.

Abstract: An optical packet node for receiving and transmitting optical packets is disclosed. A multiwavelength band splitting device splits received optical packets transmitted via multiwavelength bands into at least three groups, each group including one multiwavelength band. A multiwavelength band combining device combine the three groups of multiwavelength bands. At least two optical packet add drop multiplexers are placed between the multiwavelength band splitting device and the multiwavelength band combining device. Each optical packet add drop multiplexer adds and drops at least one individual wavelength to a respective multiwavelength band group. A load balancing stage is connected to the optical packet add drop multiplexers to provide an interconnection between at least two wavelength bands.