Abstract: An optical communication system is configured to transmit and receive at least four multiplexed, differently-polarized, optically-transmitted signals. Each signal is associated with a predefined state of polarization. An optical transmitter is configured to transmit multiplexed, differently polarized, optically transmitted signals. An optical receiver is configured to receive the optically transmitted signals. The system includes a multi-polarization analyzer circuit configured to obtain an analyzed signal for each of the polarized signals in Stokes space. The analyzer circuit is configured to determine if the multiplexed signal has been transformed by extreme polarization-dependent loss (PDL), the receiver correcting for the extreme polarization-dependent loss.

Abstract: A silt fence patch for repairing damage to silt fence is disclosed. A silt fence patch may comprise geotextile fabric, an adhesive layer, and a backing. The backing may include indicia of patches, such as patch weave direction, user instructions, or logos. A silt fence patch sheet may comprise multiple silt fence patches. The sheet may include a backing with indicia of each patch, or indicia of the patches may be printed directly on the sheet fabric. A method of repairing damage to silt fence may comprise identifying damage to the silt fence. A damage boundary may surround the damage. The method may further comprise identifying a patch size to cover the damage boundary. The method may further comprise selecting a patch having the identified patch size. Additionally, the method may comprise applying the selected patch to the damage boundary and smoothing the patch over the damage boundary.

Abstract: A silt fence patch for repairing damage to silt fence is disclosed. A silt fence patch may comprise geotextile fabric, an adhesive layer, and a backing. The backing may include indicia of patches, such as patch weave direction, user instructions, or logos. A silt fence patch sheet may comprise multiple silt fence patches. The sheet may include a backing with indicia of each patch, or indicia of the patches may be printed directly on the sheet fabric. A method of repairing damage to silt fence may comprise identifying damage to the silt fence. A damage boundary may surround the damage. The method may further comprise identifying a patch size to cover the damage boundary. The method may further comprise selecting a patch having the identified patch size. Additionally, the method may comprise applying the selected patch to the damage boundary and smoothing the patch over the damage boundary.

Abstract: Control system for electromechanical arrangements having open-loop instability. The system includes a control unit that processes sensing signals and provides control signals to maintain a movable member, such as a rotor or shaft, in the desired position. The control unit according to the invention includes a unifying plant compensation filter, which isolates the open-loop instability characteristics so that the shaft is treated as a mass having substantially no open-loop structural properties. In magnetic bearings, the open-loop instability is manifested as negative stiffness. The invention isolates the negative stiffness thus providing for better positive stiffness and improved bandwidth. Various filters, summers, and other operators required to carry out the invention are preferably implemented on a programmed processing platform such as a digital signal processor (DSP) or an arrangement of multiple digital signal processors.

Abstract: Control system for electromechanical arrangements having open-loop instability. The system is built around a control unit that processes sensing signals and provides control signals to maintain a movable member, such as a rotor or shaft, in the desired position. The control unit according to the invention includes a specially designed compensation filter, which isolates the open-loop instability so that the shaft is treated as a pure mass. In magnetic bearings, the open-loop instability is manifested as negative stiffness. The invention isolates the negative stiffness thus providing for better positive stiffness and improved bandwidth. Various filters, summers, and other operators required to carry out the invention are preferably implemented on a programmed processing platform such as a digital signal processor (DSP) or an arrangement of multiple digital signal processors.

Abstract: Control system for electromechanical arrangements having open-loop instability. The system is built around a control unit that processes sensing signals and provides control signals to maintain a movable member, such as a rotor or shaft, in the desired position. The control unit according to the invention includes a specially designed compensation filter, which isolates the open-loop instability so that the shaft is treated as a pure mass. In magnetic bearings, the open-loop instability is manifested as negative stiffness. The invention isolates the negative stiffness thus providing for better positive stiffness and improved bandwidth. Various filters, summers, and other operators required to carry out the invention are preferably implemented on a programmed processing platform such as a digital signal processor (DSP) or an arrangement of multiple digital signal processors.