A conformance testing method including: obtaining a testing symbol pattern in an optical signal; performing equalization compensation on the testing symbol pattern; generating a testing eye pattern; calculating a value of a first parameter based on the testing eye pattern and a noise enhancement coefficient, where the first parameter is used to determine a transmitter dispersion eye pattern closure degree of the optical transmitter; and when the value of the first parameter is less than or equal to a preset threshold, determining that conformance testing on the optical signal succeeds.

A method and system for providing sub-band whitening are herein provided. According to one embodiment, a method estimating an interference whitening (IW) factor based on a legacy-long training field (LLTF) signal, updating the estimated IW factor during transmission of a data symbol, and scaling the data symbol based on the updated IW factor and the estimated IW factor.

A method for comparing communication links in a communication network includes (a) obtaining first raw equalizer coefficients in a frequency domain, the first raw equalizer coefficients corresponding to a first communication link, (b) obtaining second raw equalizer coefficients in the frequency domain, the second raw equalizer coefficients corresponding to a second communication link, (c) removing time delay from the first raw equalizer coefficients to generate first corrected equalizer coefficients, (d) removing time delay from the second raw equalizer coefficients to generate second corrected equalizer coefficients, and (e) comparing the first corrected equalizer coefficients to the second corrected equalizer coefficients to determine a relationship between the first and second communication links.

A wireless communication system and a precoder device for use in such system. The precoder device includes a delay element arranged to introduce a delay to a plurality of sub-channels of a signal at a transmitter end of the communication system; wherein the delay in a plurality of sub-channels are associated with a process time of a receiver component at a receiver end of the communication system.

This application provides a symbol processing method and apparatus. The method includes obtaining, based on a plurality of complex-valued symbols, a first set corresponding to a first transmitted symbol and a second set corresponding to a second transmitted symbol, performing a copy operation on the first set and the second set so both the first set and the second set have first complex-valued symbols, and a first subset start location including the first complex-valued symbols in the first set is the same as a second subset start location including the first complex-valued symbols in the second set; and performing signal processing including a cyclic shift or frequency domain weighting on the first set and the second set. The start location and an end location of the first subset respectively correspond to locations preceding and following a first reference point of the first transmitted symbol.

A conformance testing method including: obtaining a testing symbol pattern in an optical signal; performing equalization compensation on the testing symbol pattern; generating a testing eye pattern; calculating a value of a first parameter based on the testing eye pattern and a noise enhancement coefficient, where the first parameter is used to determine a transmitter dispersion eye pattern closure degree of the optical transmitter; and when the value of the first parameter is less than or equal to a preset threshold, determining that conformance testing on the optical signal succeeds.

A method and an apparatus for self-interference cancellation in a communication device. The communication device includes an antenna configured to transmit a transmit signal and receive a receive signal through a duplexer in FDD communications, a first analog to digital converter (ADC) configured to convert the receive signal from analog to digital, a coupler configured to couple a sample of the transmit signal to a second ADC, which is configured to convert the sample of the transmit signal from analog to digital, and self-interference cancellation circuitry configured to process the digital sample of the transmit signal to generate a self-interference cancellation signal and apply the self-interference cancellation signal to the digital receive signal to cancel an amount of interference induced in the receive signal by the transmit signal. The SIC process provides additional isolation between TX signal and RX signal. The additional isolation could be utilized to relief the isolation requirement for the duplexer, reducing the cost and form factor of the duplexer.

The present invention is to generate a spatially phase modulated electron wave. A laser radiating apparatus, a spatial light phase modulator, and a photocathode are provided. The photocathode has a semiconductor film having an NEA film formed on a surface thereof, and a thickness of the semiconductor film is smaller than a value obtained by multiplying a coherent relaxation time of electrons in the semiconductor film by a moving speed of the electrons in the semiconductor film. According to the configuration, a spatial distribution of phase and a spatial distribution of intensity of spatial phase modulated light are transferred to an electron wave, and the electron wave emitted from an NEA film is modulated into the spatial distribution of phase and the spatial distribution of intensity of the light. Since the spatial distribution of phase of the light can be modulated as intended by a spatial phase modulation technique for light, it is possible to generate an electron wave having a spatial distribution of phase modulated as intended.

A example receiver includes analog circuitry configured to equalize and amplify an input signal and provide an analog signal as output; clock data recovery (CDR) circuitry configured to recover data clocks and edge clocks from the analog signal; a plurality of eye height optimization circuits, each of the plurality of eye height optimization circuits configured to, based on a respective data pattern of a plurality of data patterns, sample the analog signal based on the data clocks and the edge clocks, feed back first information to the analog circuitry for adjusting the eye amplitude, and feed back second information to the CDR circuitry for adjusting the data clocks; and an eye width optimization circuit configured to receive data and edge samples from the plurality of eye height optimization circuits, feed back third information to the CDR circuitry to adjust the edge clocks, and feed back fourth information to the analog circuitry to adjust the equalization.

Example operations may include obtaining a first received signal of a first wireless transmission by a transmitting device of a wireless signal received at a receiving device. The operations may also include obtaining a second received signal of a second wireless transmission by the transmitting device that is a retransmission of the wireless signal also received at the receiving device. The operations may further include determining, based on the first received signal and the second received signal, an equalization of distortion of propagation of the wireless signal between the transmitting device and the receiving device. In addition, the operations may include generating an equalized signal based on the determined signal equalization, wherein the equalized signal is an estimate of the wireless signal as transmitted by the transmitting device.