Abstract: The singularity problem of the constant modulus algorithm (CMA) equalizer may be overcome by implementing the CMA equalizer as a two-stage equalizer, with the first stage being a modified version of a CMA equalizer and the second stage being a conventional CMA equalizer. The first stage may be made up of four sub-equalizers, of which only two of the sub-equalizers are independent, i.e., uncorrelated to each other. This first stage equalizer may compensate for PMD. The second stage equalizer is a conventional CMA equalizer made up of four sub-equalizers that are adjusted independently. This second stage equalizer may compensate for polarization-dependent loss (PDL) and any residual CD that is not fully compensated for by a CD compensator before the two-stage equalizer. Advantageously, as the determinant of the first stage never approaches zero, the singularity problem of a conventional CMA single-stage-only equalizer is avoided by the two-stage equalizer.

Abstract: Use of a training sequence having terms that are orthogonal to each other are employed to considerably speed up execution of the LMS algorithm. Such orthogonal sequences are developed for a channel that is described as a finite impulse response (FIR) filter having a length Mnew from the already existing orthogonal training sequences for at least two channels that have respective lengths Mold1 and Mold2 each that is less than Mnew such that the product of Mold1 and Mold2 is equal to Mnew when Mold1 and Mo1d2 have no common prime number factor. More specifically, a set of initial existing orthogonal training sequences is found, e.g., using those that were known in the prior art or by performing a computer search over known symbol constellations given a channel of length M.

Abstract: Digital compensation of the polarization-mode dispersion (PMD) effects experienced by an optical signal in a transmission link is achieved. A digital representation of the optical fields of two orthogonal polarization components of an optical signal, defined by a polarization beam splitter (PBS), is first obtained. The fiber transmission link is treated as a concatenation of multiple virtual PMD segments, each having two specific principle-state-of-polarization (PSP) axes and causing a differential group-delay (DGD) and a phase delay between two signal components that are polarized along the two PSP axes. The best guesses of the parameters of the PMD segments and the relative orientation between the PSP axes of the last PMD segment and the characteristic polarization axes of the PBS are dynamically obtained. The digital representation of at least one generic component of the field of the optical signal is then computed through matrix operations by using the best guesses.

Abstract: A device employing at least one wavelength sieve/combiner that operates on discrete wavelength units and is optically interposed between an array of fibers and an array of micro mirrors which may be configured to act as in a multiplexing mode, a demultiplexing mode, a broadcast mode, and combinations of such modes. Each wavelength sieve/combiner can split a wavelength division multiplexed (WDM) beam into various discrete wavelength unit beams, combine various discrete wavelength unit beams into a WDM beam, or cause multiple copies of part or all of the wavelengths to be supplied as outputs. Typically, each fiber is associated with one wavelength sieve/combiner. Preferably, the beams between a wavelength sieve/combiner and the micro mirror array should be converging to the plane of the micro mirror array.

Abstract: Data to be impressed upon the average value of a chrominance portion of a block, is replicated at least once. The original and each replica is impressed on blocks in the same block position of separate frames. The frames that have like-positioned blocks that are carrying the same data are considered to be a group. Specific blocks of the frame may be embedded with a particular known data sequence rather than user data. Each group may employ a different known sequence. Instead of simply repeating the data for each like-positioned block of a group, the amount added to the average value for each such block may be changed slightly from frame to frame in group, even when the complexity of the blocks is the same. At a receiver, the multiple instances of the same data bit are extracted and combined to form a single received bit.

Abstract: Determining a chrominance portion to be watermarked employs a perception-based table that indicates for various pixel values which of the chrominance portions, if any, should be selected for watermarking. Only the Y, U, and V values of a pixel are needed to access the table and determine which chrominance portion should be selected. However, the table may be represented such that it may be accessed using only R, G, and B values. The table may be modified so that it may indicate which of U or V should be selected, or that neither should be selected, indicating that this pixel should not be watermarked at all. Advantageously, the table may be simplified by employing some processing, because a large section of the table may be replaced by a simple test on the pixel values, e.g., U<128, to determine the selected chrominance portion.

Abstract: A method is provided of detecting one of a set of preamble sequences in a spread signal. The method includes: (a) correlating the received spread signal with sequences of a first orthogonal Gold code (OGC) set in accordance with a first fast transform to provide a preamble signal; (b) correlating the preamble signal with the set of preamble sequences in accordance with a second fast transform to generate a set of index values; (c) forming a decision statistic based on the set of index values: and (d) selecting, as the detected one of the set of preamble sequences, a preamble sequence corresponding to the decision statistic.

Abstract: An active inductor with a smaller voltage drop with respect to the power supply voltage of an integrated circuit can be realized by an active inductor which is biased from a voltage higher than the power supply voltage, the higher voltage being generatable on the integrated circuit. Advantageously, more headroom is left for the amplifying circuit coupled to the active inductor to operate properly than with prior art active inductors. Furthermore, by not simply operating the entire active inductor from a higher voltage, the power dissipation remains the same as if the active inductor were connected as in the prior art only to the power supply voltage, and the task of generating the voltage higher than the power supply voltage is simplified, because only leakage current, e.g., nanoamps, is required.

Abstract: An optical MEMS devices is imaged to a different location at which a second optical MEMS device is located in a manner that effectively combines the tilt angles of at least one micro mirror of each of the first and second optical devices. The imaging system may reproduce the angle of reflection of the light from the first micro mirror. This may be achieved using a telecentric system, also known as a 4 f system, as the imaging system. The physical size of the arrangement may be reduced by compacting the optical path, e.g., using appropriate conventional mirrors, and/or employing folded arrangements, i.e., arrangements in which there is only one MEMS device stage that does double duty for both input and output through the use of at least one conventional mirror.

Abstract: The bit rate at which a digital wireless communications system communicates data in scattering environments may be significantly increased by using multiple antennas at both the transmitter and receiver and by decomposing the channel into m subchannels. In the same frequency band, m one dimensional signals are transmitted into a scattering environment which makes these transmitted signals appear spatially independent at the receiver antenna array. The high bit rate is enabled by special receiver processing to maximize the minimum signal-to-noise ratio of the receiver detection process.

Abstract: A graphic program configuration system is described that allows a user to create complete computer programs. In particular, the present invention improves on the prior art by providing a system and process that permits a subprogram to have an arbitrary number of outlets that may be defined at program configuration time by stimulating the subprogram to create new outlets that facilitate connecting the subprogram to other subprograms. In particular embodiments of the invention the names for the new outlets may either a) be obtained by virtue of the attempted connection of a subprogram to other subprograms or b) be provided direct entry of the outlet name by a user of the program configuration system, e.g., by typing the outlet names on the keyboard. Additionally, in accordance with an aspect of the invention, outlets can be augmented to have one or more constraining parameters that can be used to ensure that only appropriate relationships are established by connections.

Abstract: Calls to geographically limited toll-free telephone numbers, when originated from outside the predefined geographic region, are completed, but not at the called party's expense, by a) indicating to the caller that the telephone call, which otherwise will be blocked, will be completed on his behalf if the caller provides for payment of the cost of the call and b) completing the call if a signal is received from the caller indicating that the caller agrees to pay the cost of the call. Advantageously, the caller is not automatically charged for what he believed would be a free telephone call. The caller may pay for the call by charging it to any conventionally available account for charging telephone calls to which the caller is authorized to charge charges. If the account associated with the caller's telephone is selected by the caller for charging the call, a further test is made to determine if the ability to charge the cost of such geographically-limited toll-free calls to the account has been blocked.

Abstract: At least one new video signal is created by using portions taken from each signal of a plurality of original video signals to create at least one new video signal, with the sequencing of the assignments of the particular portions from any of the original video signals to any particular ones of the new video signals, or the positions therein, being the output of a cryptographic function. A cryptographic function is a function that employs a cryptographic algorithm to supply as an output an enciphered version of the values of at least one of its inputs. Because the portion assignment sequence is the output of a cryptographic function, the resulting arrangements of the portions from the original video signals within the new video signals appear random to a viewer of the new video signals. Thus, the information content of the original video signals is not intelligible when viewing the new video signals, either individually or in any combination.

Abstract: The invention relates to developing a signal to represent each block of an image contained in a frame being interpolated in a motion interpolated system such that the error between the frame being interpolated and the reference frames is minimized without placing any predetermined limitation on the values of either the weights or the displacements employed as motion vectors. The weights and displacements required to achieve the minimization of the interpolation error are jointly determined on a block by block basis. A set of groups having a candidate displacement from each reference frame and, in accordance with an aspect of the invention, their corresponding best weights are determined. An error signal which would result if each member of the set of groups of candidate displacements from each reference frame and their corresponding best weights were employed to represent the block is evaluated.