Abstract: We experimentally demonstrate a coherent transmission system with a high symbol rate using up to 110-GBaud PDM-QPSK signals. Super-Nyquist-filtering technology is used to narrow down the bandwidth of a single channel on a 100-GHz grid. The performance of the high baud rate electronic time division multiplexed-based super-Nyquist-filtered signal is also studied under the aggressive optical filtering elements in multiple reconfigurable optical add-drop multiplexers (ROADMs) nodes during transmission. We successfully transmit 100-GHz-grid, 20 channel single-carrier 440-Gb/s super-Nyquist 9-QAM-like signal over 3600-km ultralarge effective-area fiber (ULAF) at a high net SE of 4 b/s/Hz (after excluding the 7% hard-decision FEC overhead). The highly filtering tolerant performance of the 9-QAM liked super-Nyquist signal is also experimentally demonstrated. Using this scheme, we then successfully transmit ten channel 440-Gb/s signal over 3000-km ULAF and ten cascaded 100-GHz-grid ROADMs based on the 110-GBaud QPSK. Such signal is coherently detected and processed after a real-time oscilloscope at 160-GSa/s sampling rate with 65-GHz bandwidth.

Abstract: Systems, devices and techniques for processing received QPSK modulated optical signals include sampling the received signal at twice the baud rate, thereby producing samples that are then processed as 9-QAM symbols using a decision directed least squares optimization method. A third stage of channel equalization is filtering performs channel equalization to mitigate linear filtering effects along the transmission link. Data bits are then recovered from the resulting symbol estimates. The received optical signal may also include dual polarized signals for increased bandwidth capacity.

Abstract: We experimentally demonstrate long-haul WDM transmission of 36GBaud four-subcarrier Terabit PM-16QAM super-channel. Digital pre-distortion enables ~50% reach improvement for both LAPSCF and SSMF fiber-types, with maximum recorded reach of 2272km and 949km, respectively. Introduction Next generation optical networks are expected to evolve from fixed channel-grid to a flexible channel-grid, capable of supporting variable data rates and modulation formats. Consequently, ~30% improvement in spectral efficiency (SE) is expected: sufficient to satisfy the forecasts of traffic growth in medium term. The flex-grid networks allow for increase in SE by packing different channels closely together forming a super-channel structure. Increase in SE can also be achieved by using both high-order modulation formats and high baud-rate (>25GBd), leading to reduced system costs. In order to support such network upgrades, next generation optical systems will rely on digital pulse shaping and digital to analog converters (DACs) IQ-modulator drive signals. Polarization multiplexed (PM) 16QAM based transmission of baud-rates above conventional 30GBd (net baud-rate) is severely limited by the finite RF bandwidth and effective number of bits (ENOB) of DAC, and nonlinearities of MachZehnderModulator (MZM) based IQ-modulators and driver amplifiers. It is thus critical to pre-compensate these effects at the transmitter, in order to realize feasible higher baud rate transmission. Recently, high baud rate transmission experiments have been reported using electronic time division multiplexing, wide bandwidth photodiodes, etc.. In this paper, we employ pre-distortion of an integrated commercial DAC (3-dB bandwidth of ~16GHz), and an IQ-modulator, using 1.67samples/symbol. We report WDM transmission of 36GBd four-subcarrier 1.152Tb/s super-channel over standard single mode fiber (SSMF) and large area pure silica core fiber (LAPSCF), enabling transmission reach of 949km and 2272km, respectively. DAC and Driver Amplifier Transfer Function The overall transfer function of the DAC and driver was determined by generating sinusoids of varying frequency, and measuring the root mean square voltage at the output of the driver amplifer. The relative RF output power of the amplifier versus frequency for all of the four DAC ports are plotted in the Fig. 1. It can be seen that the combined 3-dB bandwidth of DAC and driver is ~16 GHz for all four channels. Fig. 1: Transfer function of DAC and driver. In addition to the DAC induced performance degradations, IQ-modulator also has a frequency dependent response which is reduced to half at the frequency of ~15GHz compared to DC which further deteriorates the performance. Terabit Super-channel: Digital Pre-distortion and Generation A pseudo-random-bit-sequence (PRBS) of order 13 was chosen as transmit data. The transmit data was first mapped to 16-QAM symbols followed by upsampling and rootraised-cosine (RRC) filtering with a roll-off factor (RO) of 0.2 to limit bandwidth and minimize inter-subcarrier crosstalk. Using the experimentally measured joint transfer function of the DAC and driver, we applied pre-distortion of low pass filtering effects in frequency domain. In addition to the DAC and driver pre-distortion, additional correction for the IQ-modulator’s effects also in frequency domain was employed. Using only 1.67samples/symbol, pre-distortion was applied through Eq. 1: similar to zeroforcing equalizer. 0 4 8 12 16 20 24 28 32 -18 -15 -12 -9 -6 -3 0 Frequency [GHz] N o rm al iz ed p o w er [d B ] HI

Abstract: The invention discloses a baud rate adaptive method for a universal asynchronous receiver/transmitter (UART), a device and the UART. The method comprises a step of measuring the width of the initial bit pulse of a received asynchronous serial signal with a preset clock cycle as a unit and obtaining the number of preset clock cycles in the initial bit pulse, wherein the preset clock frequency is N times of the least common multiple of all optional baud rates of a sending party, and N is a positive integer; a step of dividing the preset clock frequency by the number to obtain the transmission baud rate of the received asynchronous serial signal, a step of taking the transmission baud rate as the baud rate of the received asynchronous serial signal to receive the asynchronous serial signal. According to method, the device and the UART, the width of the initial bit pulse is measured through the preset clock cycle, the duration of the initial bit pulse is obtained, thus the baud rate of the asynchronous serial signal sent by the sending party can be obtained, and the asynchronous serial signal can be correctly received through an asynchronous receiving and sending transmitter with the transmission baud rate.

Abstract: Exchange of information has always been important. Without this it is impossible to express one's thoughts and ideas. A study in the various modes of communication has bridged this gap enabling an easy and free flow of information among the people. There has always been an effort to develop various ways and methods to make the transfer of information and data, even more efficient. One such study is in the transfer of serial data over a limited distance i.e., within a particular range. To meet the present day technology needs, data transfer at higher speeds is to be achieved which is possible by RF Communication. This project uses an RF Module to transfer serial data in a better way reducing the cost overhead and limiting the drastic effects of noise. In this project we have two sections, one is transmitter section and the other is receiver section. The transmitter section mainly consists of ATMEL8 and an RF Transmitter. The same is also used in the receiver section. It also involves a wireless LCD Display to display the information transferred. Arduino is used as an ISP (In-System-Programmer). This allows us to use the board to burn the boot loader onto an ATMEL. An antenna is also used at both the transmitter and receiver sections. In this method of serial communication, the maximum baud rate is 8000 bits per second. It can be used within a range of 150metre radius (with obstacles). It also has an error checking feature by which the noise is reduced. For the transfer of information within a short range, this method can be employed as it is more efficient when compared to the prevalent methods of data transfer.

Abstract: Disclosed is a baud-rate automatic matching method for a controller and a CAN bus, that is, a plurality of kinds of standby standard baud rates are stored in the controller and the controller is connected to the CAN bus; the default baud rate of the controller is set; the controller receives a message sent by the CAN bus; whether baud-rate matching is successful is judged according to whether the message sent by the CAN bus and received by the controller is correct; if the message sent by the CAN bus and received by the controller is incorrect, values in a built-in error count accumulator of the controller are accumulated; and whether to execute resetting of the baud rate of the controller is determined according to whether the value of the error count accumulator reaches a preset value. The method realizes baud-rate automatic matching between the controller and the CAN so that the controller is applicable to CAN buses of different fixed baud rates and universality and transportability of the controller are improved.

Abstract: Data Acquisition (DAQ) and Telemetry are part of the winning formula of any race team or vehicle manufacturer. It is vital to the development phase of a vehicle, so that designs can be validated and tunable parameters adjusted to increase performance and efficiency. Existing DAQ systems fail as they are of universal application type and turn out to be extremely costly and power hungry. Also, the lack of filtering stages is an issue for sensor data coming from a moving vehicle. The system discussed in this paper was designed specifically for automotive application, taking into account the size, cost and performance, while also taking care of the noise factor by including digital filters. The system was found to be 2.2 times more cost effective than current modules, with a data rate of 9600Hz and 10 bit resolution for DAQ and the telemetry system working at a serial data baud rate of 9600 transmitted wirelessly through a ZigBee network.

Abstract: A technique for frame synchronization in a communication system includes performing symbol correlation on received signal samples. A determination is made as to whether a magnitude of the symbol correlation is greater than a first threshold. In response to the magnitude of the symbol correlation being greater than the first threshold, an indication is provided that the received symbol is a valid symbol (e.g., a SYNCP symbol or SYNCM symbol). In response to the magnitude of the symbol correlation being less than the first threshold, an indication is provided that the received symbol is an indeterminate symbol (e.g., an invalid symbol or a SYNCM/2 symbol).

Abstract: We experimentally demonstrate a multidimensional global optical spectral shaping optimization based on genetic algorithm for fiber nonlinearities mitigation in a 56-GBd PDM-QPSK transmission system. The proposed method increased maximum reach by 24%, reducing transmission penalties by up to 1.8 dB.

Abstract: A method and apparatus for controlling a vehicle based transmitter/receiver system including transmitting a first signal portion at a first baud rate and second signal portion at a second baud rate where the first baud rate is faster than the second baud rate, the first signal portion including a wake-up portion, and controlling the receiver to periodically wake up to receive the first signal portion and stay awake to receive the second signal portion only if the wake-up portion of the received signal is valid.

Abstract: On-chip at-speed eye measurements of digitized signals in data and timing recovery circuits are disclosed. Eye diagrams and jitter measurements are used to evaluate signal quality and bath-tub Bit Error Rate characteristics in baseband communication systems. This disclosure describes a method and apparatus for digitally sampling a received signal at speed to produce an eye diagram of the received signal. This involves adding a small amount of circuitry to the existing prior art systems that use an interpolator for timing recovery and data recovery. In the present disclosure a temporary offset is applied to the interpolation index of the interpolator to obtain interpolated samples between the baud center and baud edge. The eye diagram can be produced from the received digitized and interpolated signal before equalization, or alternatively from the equalized signal.

Abstract: The invention relates to a controller area network (CAN) bus Baud rate self-adapting method. The CAN bus Baud rate self-adapting method includes the steps of (1) performing measurement to obtain a Baud rate measurement value; (2) calculating values which are 1 to 5 times the Baud rate measurement value and converting the values into proximate values in a stand Baud rate table to obtain A values in a measurement Baud rate table; (3) setting a Baud rate of a main controller according to the values in the measurement Baud rate table, wherein Baud rate matching is successful if a received message is correct, the message is received again if the received message is erroneous and error count does not reach a threshold value X, and other values in the measurement Baud rate table are used for replacement if the error count reaches the X until all A values are tried; (4) if the A values in the measurement Baud rate table are tried in failure, using a dichotomy to poll the next Baud rate value in the standard Baud rate table with the Baud rate measurement value as the center, and performing resetting unit the received message is correct. Compared with normal Baud rate polling methods, the CAN bus Baud rate self-adapting method is capable of rapidly positioning actual Baud rates, saving self-adapting time and improving efficiency.

Abstract: A method of encoding a first bit and a second bit for transmission on a transmission band is provided. The method includes: mapping, via a mapping component, the first bit and the second bit into a first symbol; mapping, via the mapping component, the first bit and the second bit into a second symbol; dividing, via a dividing component, the transmission band into subcarriers; allocating, via an allocating component, the first symbol to a first subcarrier of the subcarriers; allocating, via the allocating component, the second symbol to a second subcarrier of the subcarriers; and differentially encoding, via a differential encoder, the first symbol and the second symbol.

Abstract: Described is an apparatus which comprises: a Decision Feedback Equalizer (DFE); and a phase detector, operationally coupled to the DFE, to set a sampling phase based on a first post-cursor value of a composite pulse response being substantially equal to zero when the phase detector collects data bits having current bit and next bit such that value of the current bit is unequal to a value of the next bit.

Abstract: Wireless power transmission (WPT) via electromagnetic resonance has been focused on by researchers in related fields. Also, a multi-hop wireless power transmission system successfully extends power transmission distance by using multiple resonators. Sending data along with electrical power is one of the most important but missing pieces for the realization of the multi-hop WPT system. Different from radiative approach based on antennas, switching speed of waveform on the resonators is significantly slower because of resonance. Therefore it is very difficult to increase symbol rate of communication. To overcome this problem, we exploit the fact that signal-to-noise ratio (SNR) is higher in WPT because input power level is typically high. In this paper we adopt Multilevel Amplitude-Shift Keying (Mary ASK) to increase bit per symbol rather than symbol rate, aiming to improve the bit rate. We evaluate the communication performance of a multi-hop WPT system and focus on M-ary ASK for high communication speed. We conduct the experiment using M-ary ASK modulation and show the system throughput via the symbol rate and optimized bit per symbol (Log 2 M) for M-ary ASK.

Abstract: The invention provides a method and apparatus for baud rate self adaption, and equipment. According to the invention, a first device receives an input signal from a second device; the pulse width of the input signal is detected and thus a baud rate of the second device is determined; and according to the baud rate, a frequency division signal is calculated, so that the first device can adjust the baud rate that can match the baud rate used by the second device. According to the scheme in the invention, baud rate self adaption can be realized, thereby bringing convenience for data transmission between devices.

Abstract: Transmission of a single-carrier 448 Gb/s dual-polarization 16-QAM signal is demonstrated using fixed look-up table based maximum-a-posteriori detection at the receiver to mitigate pattern-dependent distortion in the transmitted signal arising from the high baud rate.

Abstract: The invention discloses an RS485 communication interface automatic baud rate and communication address detection method. The method includes the steps that when a mainframe is connected with a single slave, the mainframe sends a fixed handshake protocol in a broadcast mode at one baud rate each time till the slave resounds so as to set up communication connection; when the mainframe is connected with multiple slaves, the mainframe sends a handshake protocol to each slave address, when the slave conducts decoding and determines that the handshake protocol is sent to the slave, the salve responds to a station number given by the mainframe, and when the slave conducts decoding and determines that the handshake protocol is not sent to the slave, the slave does not respond; when the mainframe receives the response from the slave, decoding is conducted, communication connection is set up, the baud rate and the station number which are in communication with the slave are recorded, and next circulation is started if no response is received. According to the method, the automatic baud rate and the communication address of an RS485 port can be accurately detected, communication connection between the mainframe and the slaves can be conveniently achieved, extra expenses of hardware are omitted, and errors caused by interference during communication are avoided as well.

Abstract: The invention discloses an automatic MODBUS-RTU communication baud rate matching method. The method is achieved through the steps of firstly, setting the baud rate of a serial port as the default baud rate when a slave station is powered on, waiting for receiving a serial port message on a bus, resetting the baud rate of the serial port as the agreed next baud rate of a master station and the slave station if the messages unceasingly received five times are wrong messages till a correct serial port message is received, and achieving communication with the master station with the baud rate; secondly, changing the baud rate of the master station under the normal communication condition, detecting whether the received message on the bus is correct or not in real time through the slave station, repeatedly executing the baud rate matching process if the wrong messages are unceasingly received five times till the correct message is received, judging the data format based on a MODBUS communication protocol according to whether the message received by the slave station is correct or not, and conducting verification, wherein a CRC verification code and the length of the whole message are mainly verified. By means of the method, the baud rate of the master station and the baud rate of the slave station can be automatically matched without changing bus communication or all devices arranged on the bus.

Abstract: The invention discloses an automatic Baud rate detection method. According to the method, a Baud rate counter counts continuously from a start moment to a first moment, from the first moment to a second moment and from the second moment to a third moment to obtain a first Baud rate value, a second Baud rate value and a third Baud rate value respectively; a Baud rate generator of an asynchronous receiving transmitter uses the first Baud rate value, the second Baud rate value and the third Baud rate value as the Baud rate to generate a first Baud rate synchronous signal, a second Baud rate synchronous signal and a third Baud rate synchronous signal; received data which are received with the Baud rate synchronous signals as sampling points and appointed data are compared, and the automatic Baud rate detection is completed if the received data and the appointed data are identical. According to the automatic Baud rate detection method, start bit time detection and semi-bit detection are further included. The invention further discloses an automatic Baud rate detection module which comprises a precision Baud rate detection unit, a start moment detection unit, a semi-bit detection unit and a data frame matching detection unit. According to the automatic Baud rate detection method and the automatic Baud rate detection module, more precise and faster automatic Baud rate detection can be provided compared with the prior art.

Abstract: The invention discloses a timer waveform recording based serial communication method, and mainly solves the problems of dependence of Baud rate stability and poor anti-jamming capability during analog serial communication in the prior art. The implementation procedures include a receiving procedure and a sending procedure. The receiving procedure includes: capturing occurrence time for a rising edge and a falling edge for receiving data by using a capture function of an MCU (microprogrammed control unit) timer to achieve the purpose of recording data waveforms, and then calculating occurrence time of captured waveforms to obtain received data. The sending procedure includes setting timer cycles according to the analog serial Baud rate, starting the timer, setting a state of an analog serial sending data pin according to data bits of data needing to be sent in each cycle, and stopping the timer after data of one byte are sent. The method has good fault tolerance under the circumstance that the Baud rate has deviation, can effectively remove false triggering signals, and can be applied to an MCU with few hardware serial resources to realize serial communication.

Abstract: We experimentally demonstrate 16.77-Tb/s multichannel Nyquist WDM using multiple subchannels per modulator to allow optimization of baud rate and nonlinear performance. After 400-km transmission, the 257 65.3-Gb/s bands had an average BER of 2.3 10-3.

Abstract: Disclosed are a wireless communication method of improving frequency efficiency based on a channel function in a wireless communication system and an apparatus thereof. The wireless communication system using a digital modulation scheme, includes: a transmitting apparatus which modulates a data signal to generate a modulation symbol, generates a channel symbol function corresponding to the modulation symbol, combines the modulation symbol with the channel symbol function to generate a transmission symbol to transmit the generated transmission symbol through a transmission antenna; and a receiving apparatus which receives the transmission symbol through a reception antenna, estimates a channel symbol function included in the transmission symbol, and extracts the data signal based on the modulation symbol included in the transmission symbol.

Abstract: The invention provides an audio communication self-adaption baud rate method and device and a USB key. The audio communication self-adaption baud rate method and device and the USB key are suitable for the technical field of audio communication. The method includes the steps that data streams sent by a mobile terminal are received, wherein the data streams include different-frequency audio analog signals; the first-frequency audio frequency analog signal of two continuous audio analog signals is sampled to obtain a first sampling value, and the second-frequency audio frequency analog signal of the two continuous audio analog signals is sampled to obtain a second sampling value; the first sampling value and the second sampling value are converted to binary numbers according to a preset conversion mode; whether the synchronous code of the binary number is a preset synchronous code or a preset synchronous code obtained after bitwise not treatment is identified, and the conversion mode of the first sampling value and the second sampling value is configured according to the recognition result of the synchronous code; communication between the device and the mobile terminal is carried out according to the configured conversion mode. In addition, according to the preset conversion mode, the first sampling value is converted to the binary number 0, and the second sampling value is converted to the binary number 1.

Abstract: The invention relates to a fire alarm controller loop unit and a control method thereof. The fire alarm controller loop unit is characterized in that a central controller is used for sending an address pulse signal and a command pulse signal and receiving a feedback digital signal; a switching circuit is used for sending an address pulse signal to field equipment on two buses, and providing a working power supply; a pulse modulation circuit is used for sending a command pulse signal to the field equipment on the two buses; a return code current circuit comprises a high-end current mapping circuit, a low-end sampling circuit and an amplifying circuit, and the high-end current mapping circuit is connected with the amplifying circuit after connected with the low-end sampling circuit; and the amplifying circuit is connected with the central controller through an analog-digital converter. According to the control method of the loop unit, on the premise that a baud rate is not increased, fire alarm information can be simultaneously reported in 2.1 seconds even though hundreds of detection points upload fire alarm information in the same polling period, so that the response time of fire alarm is shortened greatly.

Abstract: The utility model discloses an automatic baud rate detection module which includes an accurate baud rate detection unit, a start bit time detection unit, a half bit detection unit, a data frame matching detection unit and an OR gate. The OR gate has three input terminals and one output terminal; the accurate baud rate detection unit includes a baud rate counter, the input of the accurate baud rate detection unit is received data, and the output of the accurate baud rate detection unit is selected baud rate; the input of the data frame matching detection unit is the received data and a baud rate synchronous signal, and the output of the data frame matching detection unit is connected with a first input of the OR gate; the input of the start bit time detection unit is the received data, and the output of the start bit time detection unit is connected with a second input of the OR gate; the input of the half bit detection unit is the received data and the baud rate synchronous signal, and the output of the half bit detection unit is connected with a third input of the OR gate; and the output of the OR gate is baud rate detection error indication. The automatic baud rate detection module of the utility model can realize automatic baud rate detection which is more accurate and faster compared with the prior art.

Abstract: The invention belongs to the technical field of serial communication, and particularly relates to an implementation method for achieving self-adaption of the baud rate The method includes the following steps of setting the format of a serial communication data package, detecting the baud rate and automatically adjusting the baud rate The method solves the technical problem that an existing technology can meet different design requirements for the baud rate unless external equipment is provided and cannot achieve self-adaption of the baud rate The method has the advantages that when the method is utilized to carry out serial communication with other subsystems, labor hardware jumper arrangement or program selection is needless, and plug and play performance is achieved; the baud rate used at present can be automatically analyzed according to the serial communication data package, the baud rate of a system is automatically adjusted to be baud rate used at present, and thus the system is universally used for different baud rate systems