A system may include a first module at a far end, and an optical fiber coupled to the first module. The system may also include a second module at a near end that is configured to generate and transmit instructions to the first module to control operation of the first module.

A transimpedance amplifier converts an input current to a differential signal and outputs the differential signal. The transimpedance amplifier includes a single-ended amplifier configured to convert a current signal to a voltage signal, a first feedback circuit configured to generate a bypass current, a differential amplifier circuit configured to generate the differential signal in accordance with the difference between the voltage signal and a reference voltage signal, and a detector circuit configured to detect a start and an end of a burst optical signal. The detector circuit detects the end of the burst optical signal based on a peak value of the positive-phase component and a peak value of the negative-phase component and switches the time constant of the first feedback circuit from a first time constant to a second time constant smaller than the first time constant in response to detecting the end of the burst optical signal.

An optical receiver includes photodetectors each provided on a corresponding channel of multiple channels and configured to detect an optical signal at the corresponding channel, a delay adjuster circuit provided before the photodetectors and configured to adjust a delay time of an optical waveform of an incoming signal on at least one channel, and a processor that controls the delay time such that a change point of a first optical waveform of a first channel is away from a data decision timing of a second optical waveform of a second channel, using information acquired from an electrical signal produced after photo-detection.

Disclosed in various embodiments of the present invention are a method and a device, the device comprising: an antenna module configured to form a plurality of beams having different directions; and a processor operatively connected to the antenna module, wherein the processor is configured to select a partial reception beam from among a plurality of reception beams, measure the reception power of the selected reception beam, determine a transmission condition through an artificial neural network on the basis of the measured reception power, and determine a reception beam for a communication connection by using the artificial neural network corresponding to the transmission condition. Various embodiments are possible.

Disclosed is a baud rate tracking and compensation apparatus comprising: a clock generating component generating a clock; a sampling circuit sampling a reception signal according to the clock and thereby generating a sampled result, and the sampling circuit generating a transition notification signal when the sampled result indicates a transition of the reception signal; a clock counting circuit counting cycles of the clock between a first transition of the reception signal and a second transition of the reception signal according to the clock and the transition notification signal; a bit counting circuit counting bit(s) between the first transition and the second transition according to the clock and a bit cycle; and a calculation circuit dividing the number of the cycles by the number of the bit(s) to obtain a calculation value, and then updating the bit cycle according to the calculation value.

System and method of adapting thresholds for constellation selection based on statistic distributions of received data symbols. To determine an adapted threshold, an expected ratio of received symbols with values in a certain range is preset based on an expected statistic distribution of data symbols across the multiple constellations. A first and a second ratios are defined based on the expected ratio, the first ratio being the expected ratio minus an error ratio and the second ratio being the expected ratio plus the error ratio. A first value is determined which makes the received symbols in a firs range to constitute the first ratio of a set of slicer inputs. A second value is determined which makes the received symbols in the second range to constitute the second ratio of a set of slicer outputs. The adapted threshold is then obtained based on the first and the second value.

A PAM reception circuit includes a first comparison circuit that outputs a first bit value in two-bit values based on a result of a comparison between a reception signal of pulse amplitude modulation 4 in which the two-bit values are associated with four potential levels divided by three threshold values by gray codes and a first threshold value which is a center of the three threshold values, an absolute value circuit that outputs an absolute value of a difference between the reception signal and the first threshold value or a negative value obtained by inverting a sign of the absolute value from a positive sign to a negative sign, and a second comparison circuit that outputs a second bit value in the two-bit values based on a result of a comparison between a second threshold value which is larger than the first threshold value in the three threshold values.

An example of an isolation sensor package is disclosed to include a first Integrated Circuit (IC) chip and a second IC chip. The first IC chip may include an input interface circuit that receives an input signal from a first input signal terminal and a second input signal terminal, where the input signal ranges between a first positive voltage and a first negative voltage. The first IC chip may further include a negative voltage generator that generates a second negative voltage, a level shifter that receives an output of the input interface circuit and generates a modified signal having a voltage level between a ground voltage provided to the ground terminal and a second positive voltage that is present at a voltage supply terminal. The first IC chip may further produce a signal based on the modified signal generated by the level shifter.

An optical data circuit includes threshold adjustment circuits to perform threshold adjustment compensation of asymmetrical optical noise. The optical data circuit includes an optical-to-electrical conversion circuit configured to produce first and second differential electrical data signals, at respective first and second electrical nodes, in response to an optical data signal. First and second digital-to-analog converter (DAC) circuits are each respectively coupled to the first and second electrical nodes and configured to respectively generate first and second adjustment signals. The first and second DAC circuits are configured to adjust the first and second differential electrical data signals such that a zero-crossing point of positive data is pulled up in response to the first adjustment signal and a zero-crossing point of negative data is pulled down in response to the second adjustment signal.

An optical transmission method (10) comprising steps of receiving (12) a communication signal comprising symbols for transmission. The method comprises performing (16) linear amplitude modulation of an optical carrier with the communication signal to generate an amplitude modulated optical carrier. The method comprises performing low-pass filtering (14) to reduce a bandwidth of the symbols to less than a Nyquist bandwidth of the symbols. The method comprises transmitting (18) the amplitude modulated optical carrier. The method further comprises receiving (20) the amplitude modulated optical carrier following transmission and performing direct detection of the received amplitude modulated optical carrier to generate a received electrical signal; and determining (22) received symbols from the received electrical signal using an indication of a nonlinear impulse response of the direct detection.