摘要:
An optical spectral coding scheme for fiber-optic code-division multiple-access (FO-CDMA) networks. The spectral coding is based on the pseudo-orthogonality of FO-CDMA codes properly written in the fiber Bragg grating (FBG) devices. For an incoming broadband optical signal, the designed Bragg wavelengths of the FBG will be reflected and spectrally coded with the written FO-CDMA address codes. Maximal-length sequence codes (M-sequence codes) are chosen as the signature or address codes to exemplify the coding and correlation processes in the FO-CDMA system. By assigning the N cyclic shifts of an M-sequence code vector to N users, the invention achieves an FO-CDMA network that can support N simultaneous users. The FO-CDMA encoding/decoding devices consist of a series of FBGs. To overcome the impact of multiple-access interference (MAI) on the performance of the FO-CDMA system, the FBG decoder is configured on the basis of orthogonal correlation functions of the nearly orthogonal M-sequence codes.
摘要:
A method to detect and remove noise in image reconstruction. The method includes integration of filters and phase unwrapping algorithms for removing speckle noise, residual noise and noise at the lateral surface of height discontinuities. The method is used for generating a noise-free unwrapped phase map and hence, a successful image reconstruction of an object image.
摘要:
An optical parameter measuring apparatus for measuring optical parameters of an object includes a light source, a polarizing module, a Stokes polarimeter and a calculating module. The light source emits a light which is polarized by the polarizing module and received by the Stokes polarimeter. According to the light information generated by the Stokes polarimeter, Mueller matrixes of linear birefringence, circular birefringence, linear dichroism, circular dichroism and linear/circular depolarization of the object, and Stokes vector established according to the Mueller matrixes, the calculating module calculates the optical parameters.
摘要:
A dynamic floating input D flip-flop (DFIDFF) is provided. The DFIDFF includes a floating input stage, a first string of transistors, and a second string of transistors. At a pre-charge period, the floating input stage transmits the input data to the first string of transistors; the first string of transistors stores the logic status of the input data, and pre-charges its output node to a first level. At an evaluation period, the first string of transistors decides its output node level in accordance with data logic status stored in the first string of transistors; and the second string of transistors decides output level of the D flip-flop in accordance with logic status of the output node of the first string of transistors.
摘要:
A voltage comparator includes an input portion, an output portion, and a diverting portion. The input portion accepts a first voltage and a second voltage and then outputs a first current based on the first voltage and outputs a second current based on the second voltage. The output portion outputs a result signal based on a difference between the first current and the second current. The diverting portion is electrically connected to the input portion and diverts a portion of the higher current amongst the first current and the second current.
摘要:
A divider is provided. The divider includes a first flip-flop, a flip-flop array, a first NOT gate, a second NOT gate, and a circuit. The first flip-flop can be triggered by a frequency signal. The first NOT gate is coupled between a positive output terminal of the last second flip-flop and the first flip-flop. The second NOT gate is coupled between the positive output terminal of the last second flip-flop and the circuit. The first NOT gate and the second NOT gate are controlled by the mode control signal for enabling. If N is an odd number, the circuit includes a wire, and if N is an even number, the circuit includes a third NOT gate.
摘要:
This invention revealed and demonstrated a method of measuring and deriving a Jones Matrix of a fiber or fiber component, and to compensate the fiber or fiber component such that the fiber or fiber component plus the compensated optical circuit act as if an Unitary Matrix free space condition. In this way, all compensated fibers or fiber components act the same no matter what their original conditions are. It greatly enhances the fiber or fiber component repeatability and stability throughout the fiber or fiber component production line. The compensated circuit for Unitary Matrix can be applied externally or internally.
摘要:
This invention revealed and demonstrated a method of measuring and deriving a Jones Matrix of a fiber or fiber component, and to compensate the fiber or fiber component such that the fiber or fiber component plus the compensated optical circuit act as if an Unitary Matrix free space condition. In this way, all compensated fibers or fiber components act the same no matter what their original conditions are. It greatly enhances the fiber or fiber component repeatability and stability throughout the fiber or fiber component production line. The compensated circuit for Unitary Matrix can be applied externally or internally.For the external approach, for example, compensators such as variable retarder and half-wave plate may be added, or equivalently polarization controllers may be employed. For the internal approach, no component is added, and the compensation is realized through fiber bending, twisting or other means at either or both ends of a fiber or fiber component.The disclosed free space single-mode fiber invention not only greatly enhances repeatability in the fiber and fiber component production line, it also can be employed to accelerate the design simulation for optical circuit optimization of optical fiber sensors employed fiber and fiber coil such as fiber optic gyros.
摘要:
A driving circuit applied in an electronic display apparatus is provided. The driving circuit includes a first exchange circuit and a first buffer. The first buffer includes first and second input stages, a second exchange circuit and first and second output stages. The first exchange circuit selectively couples a first input signal and a first output signal outputted from the first output stage to one of the first and the second input stages; and selectively couples a second input signal and a second output signal outputted from the second output stage to the other of the first and the second input stages. The second exchange circuit selectively couples the first input stage to one of the first and the second output stages and selectively couples the second input stage to the other of the first and the second output stages.
摘要:
A dynamic floating input D flip-flop (DFIDFF) is provided. The DFIDFF includes a floating input stage, a first string of transistors, and a second string of transistors. At a pre-charge period, the floating input stage transmits the input data to the first string of transistors; the first string of transistors stores the logic status of the input data, and pre-charges its output node to a first level. At an evaluation period, the first string of transistors decides its output node level in accordance with data logic status stored in the first string of transistors; and the second string of transistors decides output level of the D flip-flop in accordance with logic status of the output node of the first string of transistors.