A signal transmission method includes receiving, by a controller, a request signal sent by a first transmitter. The method includes establishing, by the controller according to the request signal, a second optical path that connects the first transmitter to the second receiver in the optical switching network (OSN). The method includes sending, by the controller, to the second receiver according to the request signal, a reset signal used to instruct the second receiver to be reset to an initial state. The method includes sending, by the controller, an acknowledgement signal to the first transmitter, by using the second optical path, an optical signal to the second receiver.

The invention provides an optical interconnect system and method for a data center. A nonlinear differential precoding module performs nonlinear differential precoding on an inputted original signal, to obtain a precoded signal with an increased quantity of levels. A generalized Tomlinson-Harashima precoding (GTHP) module pre-equalizes the precoded signal, to obtain a pre-equalized signal with scattered distribution. A faster than Nyquist (FTN) module performs high-frequency truncation filtering on the pre-equalized signal, to obtain a discrete signal. A signal transmission module transmits the discrete signal from a transmitting end to a receiving end. A feed-forward equalizer (FFE) performs strong equalization on the discrete signal to obtain a level slice signal, and decodes the level slice signal according to a GTHP decoding table, to obtain a decoded signal. A simplified 2D constellation distortion module processes the decoded signal to reshape a constellation, and obtains a restored signal according to a time interleaving method.

A receiver device includes circuitry to measure an error vector of a pulse amplitude modulation (PAM) sequence in a signal received from a transmitter and control logic coupled to the circuitry. The control logic removes estimated linear components from the measured error vector to generate a non-linear error vector. The control logic further determines, with reference to a set of lookup table (LUT) values, one or more tuning parameters for the PAM sequence based on the non-linear error vector and modifies the set of LUT values according to the one or more tuning parameters. The control logic further provides the modified set of LUT values to the transmitter, which when used by the transmitter to add digital pre-distortion to the PAM sequence, causes the non-linear error to be at least partially removed from the signal.

The present disclosure relates to a superposed signal sampling apparatus, including: a signal receiving module, a signal extracting module, and a signal output module. The signal receiving module is used to receive a superposed signal. The signal extracting module is used to determine whether the received superposed signal is within a preset threshold range of a direct current signal; if the received superposed signal is within the threshold range, extract a previously received signal as a direct current signal to be output; and if the received superposed signal is beyond the threshold range, extract a currently received signal as a direct current signal to be output. The signal output module is used to integrate the direct current signal extracted by the signal extracting module, and then output the direct current signal. The present disclosure further relates to a superposed signal sampling method.

Noise caused by and leaking from a transmit signal into a radio-frequency (RF) receive path signal is reduced by forwarding the transmit signal to a first filter or a digital processor and DAC, scaling the transmit signal and approximating the noise, subtracting first and second corrective signals from the RF receive path signal, down-converting a resulting corrected RF receive path signal, filtering the down-converted corrected signal in a second filter, up-converting the filtered corrected signal to create the first corrective signal, and up-converting the filter or DAC output signal to create the second corrective signal. The transmit signal may come from an output of an RF power amplifier, and may be down-converted prior to filtering in the first filter or processing in the digital processor. The second filter may be a series filter or a shunt filter. A radio includes the circuits to perform the above method.

A feed-forward equalizer includes a shift register, a look-up table circuit, a selection circuit and an output terminal. The shift register temporarily stores and shifts input data based on a clock signal to obtain multiple shifted input data. The look-up table circuit has multiple processed signals. The processed signals are obtained by logical operation of multiple coefficients. An input terminal of the selection circuit is coupled to the look-up table circuit. A control terminal of the selection circuit receives the shifted input data. The selection circuit selects at least one of the processed signals of the look-up table circuit as a selected signal based on the shifted input data. The output terminal provides an output signal according to the selected signal.

A receiver device includes circuitry to measure an error vector of a pulse amplitude modulation (PAM) sequence in a signal received from a transmitter and control logic coupled to the circuitry. The control logic removes estimated linear components from the measured error vector to generate a non-linear error vector. The control logic further determines, with reference to a set of lookup table (LUT) values, one or more tuning parameters for the PAM sequence based on the non-linear error vector and modifies the set of LUT values according to the one or more tuning parameters. The control logic further provides the modified set of LUT values to the transmitter, which when used by the transmitter to add digital pre-distortion to the PAM sequence, causes the non-linear error to be at least partially removed from the signal.

A feed-forward equalizer includes a shift register, a look-up table circuit, a selection circuit and an output terminal. The shift register temporarily stores and shifts input data based on a clock signal to obtain multiple shifted input data. The look-up table circuit has multiple processed signals. The processed signals are obtained by logical operation of multiple coefficients. An input terminal of the selection circuit is coupled to the look-up table circuit. A control terminal of the selection circuit receives the shifted input data. The selection circuit selects at least one of the processed signals of the look-up table circuit as a selected signal based on the shifted input data. The output terminal provides an output signal according to the selected signal.

A receiver for receiving a data signal, comprising, an analog-to-digital converter configured to convert the data signal into digital data, a first-in-first-out buffer configured to determine a frame boundary of the digital data by referring to a comma index to output the digital data in units of data frames according to the determined frame boundary, a decision feedback equalizer configured to process a data frame output from the first-in-first-out buffer through a decision feedback equalization operation, wherein feedback data used in the decision feedback equalization operation of the data frame uses a predetermined fixed pattern, and a comma detector configured to generate the comma index by comparing a determined value of the data frame with the predetermined fixed pattern. The data frame may include a preceding data field in which a message is stored and a subsequent comma field having the same bit value as the fixed pattern.

A receiver includes: a frequency-characteristic-changing-circuit to change a frequency characteristic of an input signal in which N-level data value is pulse-amplitude-modulated, to generate a frequency-characteristic-changed-signal; a controller to control the frequency-characteristic-changing-circuit to obtain a desired ratio between a amplitude component of a target data value corresponding to the frequency-characteristic-changed-signal at a first timing and a second amplitude component thereof at a second timing which is later than the first timing; and a decision-feedback-equalization-circuit to which the frequency-characteristic-changed-signal is input, wherein the decision-feedback-equalization-circuit includes: a comparison-circuit to include comparators each to output a comparison result obtained from comparing the target data value and a threshold value, and N1 selection circuits each to select one of comparison results output from the comparators at the second timing, based on the comparison results, and wherein at least one of the comparators outputs the comparison results to two of the N1 selection circuits.