Methods and devices implementing a combination of multi-dimensional pulse position modulation (PPM) with wavelength division multiplexing (WDM) or wavelength division multiplexing multiple access (WDMA) for long range space communications are disclosed. The described multi-dimensional PPM scheme can use the laser wavelength and/or polarization as the additional dimension(s) to the time dimension. Through examples it is shown that the disclosed teachings result in a higher photon information efficiency. Various exemplary embodiments are also presented to highlight the applications benefiting from the disclosed methods and devices.

A method of calibrating a signal level of a memory device includes performing pull-up code and pull-down code calibrations, using a ZQ calibration for non-return-to-zero (NRZ) signaling, performing a most significant bit (MSB) code calibration, using an MSB additional driver for pulse amplitude modulation level-4 (PAM4) signaling, and performing a least significant bit (LSB) code calibration using an LSB additional driver for the PAM4 signaling.

A memory system including: a memory controller to transmit a command, an address, or data to a first channel based on a data input/output signal having one of N (N is a natural number of three or more) different voltage levels during a first time interval, the memory controller transmitting the command, the address, or the data not transmitted during the first time interval to the first channel based on the data input/output signal having one of two different voltage levels during a second time interval; and a memory device to sample the data input/output signal received via the first channel during the first time interval in a pulse amplitude modulation (PAM)-N mode, the memory device sampling the data input/output signal received via the first channel during the second time interval in a non return to zero (NRZ) mode.

A lidar for generating long PPM waveforms includes: receiving an initial PPM code element and a desired maximum sidelobe height; b) generating a two-column lookup table; c) selecting a candidate modulation level from a pool of available elements; d) identifying the differences between the selected candidate modulation value and each of the code values in the initial PPM code and incrementing corresponding values in the lookup table; e) comparing the values of the lookup table against the desired maximum sidelobe height; f) when a value exceeds the desired maximum sidelobe height, discarding the candidate modulation level, decrementing the corresponding values in the lookup table and repeating steps c to g; g) otherwise, appending the candidate modulation level to the end of the initial PPM code to update the initial code, and repeating steps c to e N times to generate a PPM waveform of length N.

Data bits are encoded in an eleven bit seven pulse amplitude modulated three-level (PAM-3) symbol format on a plurality of data channels and two auxiliary data channels, and one or more of a cyclic redundancy check (CRC) value, a poison value, and a severity value are encoded as PAM-3 symbols on an error correction channel.

A direct radiation wireless digital communication system based on a digital programmable metamaterial, including a transmitting system and a receiving system, where information transmitted by the transmitting system is loaded to a programmable metamaterial, and is directly radiated into free space in a form of an ever-changing far-field pattern under the illumination of a feeding antenna; the receiving system collects electric field values received by receiving antennas located at different positions of a far-field region to obtain a far-field pattern, and recovers the transmitted original information according to a mapping relationship between the far-field pattern and a coding sequence. The system does not require a digital-to-analog conversion module and a frequency mixing module. The system also features an inherent secrete communication in the physical level which protects the transmitted information from being intercepted at a single point or any random points, and has the capabilities of self-adaption and self-perception.

An output power linearization method, suitable for a calibration system, includes the following operations: providing an instruction signal, which corresponding to a currently ideal output power among multiple ideal output powers, to an emission module of the calibration system so that the emission module outputs a radio frequency (RF) signal with a practical output power according to the instruction signal; obtaining a feedback signal, by a feedback circuit of the calibration system, from an output terminal of the emission module, and calculating a feedback output power from the feedback signal; calculating an output difference between the currently ideal output power and the feedback output power; if an absolute value of the output difference is larger than an absolute value of a feedback error of the feedback circuit, adjusting a present gain of the emission module so that the practical output power approaches the currently ideal output power.

An efficient communications apparatus is described for a vector signaling code to transport data and optionally a clocking signal between integrated circuit devices. Methods of designing such apparatus and their associated codes based on a new metric herein called the “ISI Ratio” are described which permit higher communications speed, lower system power consumption, and reduced implementation complexity.

A transceiver device includes a transmitter and a receiver connected to each other through a first line and a second line. The transmitter transmits signals having a first voltage range to the first line and the second line in a first mode, and transmits signals having a second voltage range less than the first voltage range to the first line and the second line in a second mode. The transmitter encodes an original payload to generate a first payload in the second mode, and transmits a clock training pattern and the first payload through the first line and the second line. The receiver decodes the first payload and outputs reception data corresponding to the original payload in the second mode.

A transmitter includes a transmission controller which outputs original data through an original data lane, an encoder which encodes the original data into encoded data and outputs the encoded data through an encoded data lane, and a transmission driver which outputs the encoded data at a speed of M (M is a real number greater than 0) gigabits per second through a transmission and reception interface. The transmission driver provides a first clock signal corresponding to an output speed to the encoder, the encoder provides a second clock signal having a second frequency less than a first frequency of the first clock signal to the transmission controller, the transmission controller outputs the original data based on the second clock signal, and the encoder outputs the encoded data based on the first clock signal.