Abstract: The present application relates to a method for performing optical time domain reflectometry (OTDR) on an optical fibre. The method comprises: a) setting (1010) a decision threshold of a photodetector; b) transmitting (1020) a first signal into an optical fibre, wherein the first signal comprises a sequence of optical radiation pulses based on a coded sequence; c) detecting (1030) optical radiation backscattered and/or reflected from the optical fibre using the photodetector; d) obtaining (1040) a measurement signal comprising bit sequences based on the detected optical radiation and the decision threshold of the photodetector; e) comparing (1050) the measurement signal with the first signal to obtain a correlation signal; f) adjusting (1060) the decision threshold of the photodetector; g) repeating (1070) steps (b)-(f) to obtain a plurality of correlation signals; and e) combining (1080) the plurality of correlation signals to obtain an OTDR trace of the optical fibre.

Abstract: Signal quality monitoring methods and systems. A signal quality monitoring method includes receiving, at a termination point of an optical link, an incoming transmission including one or more optical signals. The method further includes filtering a portion of the incoming transmission to select an optical signal from the one or more optical signals. The method also includes segmenting the optical signal by time to obtain a plurality of optical signal time segments, and generating a signal analysis plot using the plurality of optical time signal segments.

Abstract: The present application relates to a method for performing optical time domain reflectometry (OTDR) on an optical fibre. The method comprises transmitting a first signal into an optical fibre, wherein the first signal comprises a sequence of optical radiation pulses based on a coded sequence, wherein each of the sequence of optical radiation pulses are separated by a fill pattern controlled by a binary sequence of high and low values.

Abstract: Embodiments described herein provide methods and apparatuses for providing automatic configuration of ports of a first transport equipment. A method is provided in a first transport equipment for an optical network for communicating with a second transport equipment in an optical network to transmit traffic between a local terminal device and a remote terminal device. The method comprises receiving traffic from a local terminal device intended for a remote terminal device; attempting to decode the traffic according to a first coding type to generate decoded traffic; determining an alignment status of the decoded traffic; and responsive to an alignment status of the decoded traffic indicating a loss of frame, attempting to decode the traffic according to a second coding type.

Abstract: Methods and apparatus for emulating optical modules. A method includes receiving, from an optical module emulator, a first serial data stream having the plurality of upstream signals multiplexed into a plurality of bits; wherein the first data stream includes a plurality of frames, each frame having a multi-frame alignment bit; and de-multiplexing the plurality of upstream signals based on each multi-frame alignment bit within each respective frame. A method includes receiving, from an emulator controller, a second serial data stream having a plurality of downstream signals multiplexed into a plurality of bits; wherein the second serial data stream includes a plurality of frames, each frame having a multi-frame alignment bit; and de-multiplexing the plurality of downstream signals based on each multi-frame alignment bit within each respective frame.

Abstract: Methods and apparatus for emulating optical modules. A method includes receiving, from an optical module emulator, a first serial data stream having the plurality of upstream signals multiplexed into a plurality of bits; wherein the first data stream includes a plurality of frames, each frame having a multi-frame alignment bit; and de-multiplexing the plurality of upstream signals based on each multi-frame alignment bit within each respective frame. A method includes receiving, from an emulator controller, a second serial data stream having a plurality of downstream signals multiplexed into a plurality of bits; wherein the second serial data stream includes a plurality of frames, each frame having a multi-frame alignment bit; and de-multiplexing the plurality of downstream signals based on each multi-frame alignment bit within each respective frame.

Abstract: A method of frame synchronization comprises receiving a stream of bits, the stream comprising a sequence of frames, wherein each frame comprises a frame counter value representing the number of the frame in the sequence, and frame check bits for checking the validity of the frame counter value. The method comprises decoding a first section of bits, and trailing a first portion of the first section of bits as a trial counter value, and a second portion of the first section of bits as trial check bits. The method comprises checking if the trial counter value corresponds to a valid frame counter value using the trial check bits, and synchronizing based on whether the trial counter value is determined to correspond to a valid frame counter value.

Abstract: A method of frame synchronization comprises receiving a stream of bits, the stream comprising a sequence of frames, wherein each frame comprises a frame counter value representing the number of the frame in the sequence, and frame check bits for checking the validity of the frame counter value. The method comprises decoding a first section of bits, and trailing a first portion of the first section of bits as a trial counter value, and a second portion of the first section of bits as trial check bits. The method comprises checking if the trial counter value corresponds to a valid frame counter value using the trial check bits, and synchronizing based on whether the trial counter value is determined to correspond to a valid frame counter value.

Abstract: Processes for treating aqueous solutions to remove dissolved selenium species, for example in the presence of an excess of sulphate anions, which include the use of strongly basic anion exchange resins, or co-precipitation and adsorption of the selenate (and selenite) with mixed ferrous and ferric iron, or combinations thereof. Co-precipitation and adsorption of selenate may take place in an electrolytic cell in the presence of ferrous and/or ferric iron.

Abstract: Processes for treating aqueous solutions to remove dissolved selenium species, for example in the presence of an excess of sulphate anions, which include the use of strongly basic anion exchange resins, or co-precipitation and adsorption of the selenate (and selenite) with mixed ferrous and ferric iron, or combinations thereof. Co-precipitation and adsorption of selenate may take place in an electrolytic cell in the presence of ferrous and/or ferric iron.

Abstract: A decoding method for a Huffman code includes receiving a continuous stream of coded data each including a variable number of bits at least equal to a minimum number, and obtaining from each item of coded data a corresponding item of source data. The method includes providing a decoding memory structure comprising, for each value of an initial group of bits including a number not greater than the minimum number and for each value of each further bit, a record formed by a flag having an end-of-decoding value or a not end-of-decoding value and a field indicating the source data or the records associated with the values of an immediately following bit depending on whether the flag has, respectively, the end value or the not end value. The record corresponding to the value of the initial group is accessed.

Abstract: The ratio y(n) of two digital values, respectively a(n) and b(n), representing the n.sup.th elements of two respective sequences of digital input data representing two quantities slowly varying in time, is obtained by computingy(n)=y(n-1)+g*[a(n)-b(n)*y(n-1)]wherein g represents a multiplying factor. Within the domain of the z transform, the expression becomes:Y(z)=z.sup.-1 *Y(z)+g[A(z)-B(z)conv Y(z)*z.sup.-1where conv indicates an operation of convolution and which, for input sequences corresponding to signals filtered through a lowpass filter with a time constant greater than or equal to 3 msec is simplified to: ##EQU1## The approximation is exceptionally good and computation thereof may be achieved by the use of relatively simple hardware, without severely burdening the workload of a microprocessor.