Abstract: A PAM receiver for reproducing a baseband signal that symbol codes digital data is combined with an decision-feedback equalizer (DFE) incorporating first adaptive digital filtering as a feed-forward element and second adaptive digital filtering as a feedback element. The DFE response is supplied to symbol decoding circuitry for reproducing the digital data. A de-rotator re-samples the first adaptive digital filtering response before it is combined with the second adaptive digital filtering response to generate an equalizer response. The resulting baud-rate equalizer response is sampled at baud rate and quantized to generate baud-rate decisions that applied to the second adaptive digital filtering as input signal, for completing the decision-feedback loop. The re-sampling of the first adaptive digital filtering response by the de-rotator is controlled, so as to provide a phase-tracker that reduces phase noise and intersymbol interference, prior to the making of decisions for decision feedback.

Abstract: This paper introduces a simple and hardware efficient clock recovery method for high speed serial links and compares its performance with conventional techniques. Conventional methods are conceptually complex and difficult to realize since they rely on data transitions to recover the clock by oversampling the received signal. In contrast, the new method monitors one or more signal levels and aligns the clock sampling phase with the maximum vertical data eye opening by using the minimum mean squared error algorithm. Besides being easily implementable in a standard CMOS technology, this new method requires only baud rate sampling and is independent of the data transition density. Behavioral simulations predict superior performance of this method compared to a conventional bang bang phase detector based architecture.

Abstract: A diversity receiver is coupled to a composite antenna having first and second antennas physically configured to provide one or more forms of diversity reception. The multiple channel diversity receiver includes first and second RF channels with joint signal processing. First and second RF signals are processed jointly in the multiple channel diversity receiver with respect to tuning, automatic gain control (AGC), baud clock recovery, RF carrier recovery and forward equalization. The multiple channels of the diversity receiver are linked or cross coupled to each other through respective joint processing circuitry. In particular, first and second RF tuners share a common local oscillator and a common AGC feedback loop. First and second front ends share a common baud timing loop and a common pilot carrier recovery loop. Finally, first and second diversity receiver channels share a common sparse equalization filter. By processing first and second signals jointly in the diversity receiver, the receiver provides equal or superior performance to a single receiver processing only the best signal.

Abstract: A system and method for optimizing dispersion in an optical transmission line is provided. The system and method comprise measuring the amplitude of a d.c. voltage component of a synchronously demodulated data signal of at least one wavelength channel by an in-phase carrier at the baud frequency of the wavelength channel. In an alternative embodiment, the system and method comprise measuring the IF amplitude of the resulting a.c. signal of a data signal of the at least one wavelength channel comprising a received RZ signal mixed with a local oscillator, whose frequency differs from the wavelength channel baud by a relatively small amount, somewhere on the order of about 100 kHz.

Abstract: The present invention provides an electronic device consisting of a Universal Asynchronous Receiver Transmitter (UART) having its transmit data output connected to a triggered timer and a computing means that computes the transmitted baud rate from the time measured by the timer for transmitting the known data byte.

Abstract: A system and method for minimizing the frequency error of satellite modem signals at a satellite gateway. The gateway downstream baud (symbol) clock and the elements that control the upstream frequency (i.e., local oscillators in the conversion chain, A/D sample clocks) are locked to a common frequency reference. The gateway sends upstream satellite frequency offset information, such as satellite ephemeris data from which to calculate Doppler offset, to the satellite modem. The satellite modem locks the frequency of the satellite modems master oscillator to the recovered baud rate using a frequency locked loop. The satellite modem uses its master oscillator as the carrier reference for the upstream frequency up conversion. The satellite modem uses or calculates the upstream satellite frequency offset and compensates for this offset by shifting its center frequency.

Abstract: A diversity receiver is coupled to a composite antenna having first and second antennas physically configured to provide one or more forms of diversity reception. The multiple channel diversity receiver includes first and second RF channels with joint signal processing. First and second RF signals are processed jointly in the multiple channel diversity receiver with respect to tuning, automatic gain control (AGC), baud clock recovery, RF carrier recovery and forward equalization. The multiple channels of the diversity receiver are linked or cross coupled to each other through respective joint processing circuitry. In particular, first and second RF tuners share a common local oscillator and a common AGC feedback loop. First and second front ends share a common baud timing loop and a common pilot carrier recovery loop. Finally, first and second diversity receiver channels share a common sparse equalization filter. By processing first and second signals jointly in the diversity receiver, the receiver provides equal or superior performance to a single receiver processing only the best signal.

Abstract: The present invention generally relates to encoding/decoding method and device used for remote controller, which utilizes baud rate to encrypt data for transmission. The encoding device of the present invention comprises an encoder for encoding an identification code into an encrypted code; an interpreter for interpreting the un-encoded portion of the identification code and the encrypted code into a transmission signal. Wherein, when the encrypted code is in a first base, the plain code corresponding to the encrypted code will be transmitted with a first baud rate; and when the encrypted code is in a second base, the plain code corresponding to the encrypted code will be transmitted with a second baud rate. The decoding device according to the present invention comprises a receiver for receiving the transmission signal; a interpreter connected to the receiver for interpreting the transmission signal into a received signal; a encoder for utilizing the same encoding algorithm as in the transmitter to generate a comparison code; and a processor for comparing the received signal and the comparison code and for the process control.

Abstract: In an auto baud system and method, the baud rates between two communicating devices are synchronized by timing the transmission of a plurality of bits by counting the cycles of a reference clock. The number of cycles counted is then divided by the number of bits counted over and any remaining cycles are distributed evenly across the data being transmitted or received. The interface of the circuit is preferably implemented as a single pin, open drain interface which can be connected to an RS-232 communications link using external hardware.

Abstract: A diversity receiver is coupled to a composite antenna having first and second antennas physically configured to provide one or more forms of diversity reception. The multiple channel diversity receiver includes first and second RF channels with joint signal processing. First and second RF signals are processed jointly in the multiple channel diversity receiver with respect to tuning, automatic gain control (AGC), baud clock recovery, RF carrier recovery and forward equalization. The multiple channels of the diversity receiver are linked or cross coupled to each other through respective joint processing circuitry. In particular, first and second RF tuners share a common local oscillator and a common AGC feedback loop. First and second front ends share a common baud timing loop and a common pilot carrier recovery loop. Finally, first and second diversity receiver channels share a common sparse equalization filter. By processing first and second signals jointly in the diversity receiver, the receiver provides equal or superior performance to a single receiver processing only the best signal.

Abstract: A microcontroller with embedded software for automatically detecting a baud rate of an asynchronous serial bit stream during an initial set up phase of a microcontroller. The microcontroller is configured to receive a data set from a transmitter and includes a transition detector for identifying bit transitions in the data set. The microcontroller includes a timer triggered by the transition detector that is measures the time interval between two predefined bit transitions, a storage element for registering the measured time interval, and a look up table that provides defines baud rates relative to various time intervals that can be accessed to determine a nearest baud rate value corresponding to the registered time interval.

Abstract: Disclosed is a system and method for providing backward compatible transmitter diversity in an orthogonal frequency division modulated (OFDM) communication system. According to one aspect of the invention, a method for providing backward compatible transmitter diversity includes the steps of: receiving an input data bit stream; transforming it into an OFDM symbol stream comprised of even and odd symbols; dividing the OFDM symbol stream into a first symbol sub-stream and a second symbol sub-stream; processing the first symbol sub-stream by a first processing block to output a first processed symbol sub-stream; processing the second symbol sub-stream by a second processing block to output a second processed symbol sub-stream; transmitting the first processed symbol sub-stream from a first diversity antenna; and transmitting the second processed symbol sub-stream from a second diversity antenna and both are transmitted over non-overlapping frequencies.

Abstract: With the rising number of modulation types used in multiuser communication systems, we need to find efficient methods to discriminate them. Indeed, modulation recognition has become important in wireless communications for both civilian and military applications. Traditionally, to classify modulation types, most studies assume abundant a priori knowledge about modulated signals such as binary data rate, baud rate or carrier frequency. However, new transmission receiver systems need to classify automatically digital modulations without specific information. In the course of making decision on modulation type, these parameters may have to be estimated in order to perform efficient demodulation. This paper proposes a new way of estimating baud rate of digital modulated signals. This approach is based on abrupt changes detection in time-frequency plane and on abrupt change periodicity analysis using Kalman filtering.

Abstract: The Controller Area Network (CAN) is a protocol designed to manage multiplexed communications between multiple CPUs. The baud rate is up to 1Mbit/s. CAN Calibration Protocol (CCP) is a masterslave type communication protocol for online or offline calibration and monitoring. The success in development of communication module based on CCP provides the real and accurate data transmission for the electronically controlled engine calibration system.

Abstract: The MCP2150 has two independent baud rates. One of the baud rates is for communication with the Primary device (PDA). The Primary device negotiates this baud rate with the MCP2150, as defined in the IrDA standard. The second baud rate is set with the two hardware pins, BAUD1 and BAUD0. This second baud rate is for communication with the host controller. The IrDA standard is a network protocol and follows a layered approach in its definition. A model of the IrDA protocol stack is shown in Figure 2. These protocols deal with a manageable set of responsibilities and also supply needed capabilities to the layers above and below. The MCP2150 is an IrDA standard Protocol Stack Controller, which provides support for the IrDA standard protocol “stack” plus bit encoding/decoding.

Abstract: Since in a demodulated base band signal in an FSK receiver, etc. usually a DC offset is produced due to a frequency difference between a transmitter and a receiver, etc., which lowers demodulation margin, a circuit is constructed for detecting an error in a center level thereof to correct same in a simple manner. In this circuit, a bit synchronizing signal, which is at a beginning of a the base band signal EB is sampled twice with an interval of 1/(baud rate) sec and an average of two sampled values is obtained by applying sampled output pulses thus obtained to a holding capacitor in a hold circuit. In this way the error in the center level is detected and the center level is corrected by subtracting it from the base band signal in a subtracter.

Abstract: A method and apparatus to improve modulation efficiency. A symbol is created in which the relative position of a second pulse is a symbol period encode at least one bit. The symbol is transmitted across a communication channel. The one or more bits modulated by the position of the second pulse are recovered such that high bit rate communication may occur without channel compensation.

Abstract: PROBLEM TO BE SOLVED: To measure jitter by maintaining a jitter value represented by a unit interval(UI) even though the frequency of a serial data stream at a high baud rate is lowered. SOLUTION: A down-mixing stage 10 by frequency mixing down-converts a serial data stream at a high baud rate into a serial stream at a low rate without changing jitter in the UI. The serial stream is supplied to a clock recovery stage 20, an AM(amplitude modulation) removal stage 40 or an A/D converter 50. A jitter measurement stage 30 measures jitter with an output signal of the stage 20 or 40. Otherwise, a DSP(digital signal processor) 60 directly measures the jitter from an output signal of the A/D converter 50.

Abstract: Symbol by symbol variable code rate capable communication device. A communication device is operable to perform processing of a variable code rate signal whose code rate varies on a symbol by symbol basis. This may involve performing encoding of input to generate the variable code rate signal; alternatively, this may involve performing decoding of a variable code rate signal. In doing so, this approach may involve using a single encoder and/or decoder (depending on the application). In some instances, a single device is operable to encode a first variable code rate signal (for transmission to another device) and to decode a second variable code rate signal (that has been received from another device). In addition, a method of coding (including one or both of encoding and decoding) may also operate of a variable code rate signal whose code rate varies on a symbol by symbol basis.

Abstract: The design of a new multiuser line-coding scheme based on ideas from collaborative coding multiple access (CCMA) is presented. The new scheme yields good throughput in terms of user information bits per time slot (baud). Separate user data streams (or a single data stream demultiplexed into multiple separate streams) are combined in a binary adder channel. Trade-offs among the number of users, number of time slots per user symbol, and number of user information bits per user symbol are developed, and possible codes are tabulated. A maximum rate of 4.4 bits/baud can be achieved by using five time slots, with two symbols/user and 22 users.

Abstract: The performance of an optical fiber channel is degraded by some limiting factors including chromatic dispersion (CD), polarization mode dispersion (PMD), and bandwidth limitations of the receiver. Inter-symbol interference (ISI) due to the dispersion can be compensated by various methods among which using an adaptive decision feedback equalizer (DFE) provides a low power solution. In this paper we examine the optimization of the parameters in the design space of this compensation technique for directly detected fiber optical signals. In particular, we discuss the adaptive equalizer coefficients, baud rate sampling time, and slicer threshold estimation methods in order to have a fully automated DFE.

Abstract: PROBLEM TO BE SOLVED: To provide receiving processing and baud rate converting processing capable of receiving the data of all baud rates and dealing with any head character of data to be received. SOLUTION: In this apparatus, a switch is set according to the contents of head data of data to be received, a baud rate is judged on the basis of a time from the first fall to the next rise in the head data of the received data and the number of bits determined from the setting status of the switch, and this judged baud rate is set to receive the data. COPYRIGHT: (C)2005,JPO&NCIPI

Abstract: In the asynchronous serial data transmission and/or reception conducted by an asynchronous serial data communication device, an asynchronous serial data receiving device as an asynchronous serial data receiver section inputs a count correction signal (15) from a count correction circuit (2), and a control signal generating circuit (1) that generates a data shift signal (120) controls the timing for outputting the data shift signal (120) in accordance with the count value correction signal (15). The time intervals during which a serial-to-parallel conversion circuit (3) samples a communication data (4) is changed as to each data bit in accordance with this data shift signal, so that the sampling interval can be set more precisely than just a multiple of integer of the operation clock (110), thereby to improve the baud.

Abstract: A prototype of a cockpit video system for the transmission of video from an aircraft cockpit to a ground facility using a very low bandwidth satellite communications system is described. The aircraft is equipped with a satellite telephone capable of voice and 4800-9600 baud data/facsimile transmissions, using the Canadian MSAT geostationary mobile communications satellite. Consideration is also being given to utilizing the Globalstar satellite communications system, which operates at 9600 baud. In order to transmit video at these low bit rates, compression is essential. The initial prototype uses a simple motion video approach using the SPIHT wavelet compression algorithm on a frame by frame basis. The objective of this work is transmission of reasonable quality video with frame rates on the order of 0.5 Hz. A rate of 0.37 Hz has been demonstrated in initial testing.

Abstract: Publisher Summary This chapter discusses distributed systems. Cabling is one of the most costly parts of any control scheme. For a serial communication system to work, there needs to be a consistency between the transmitter and the receiver. The theoretically simplest way to achieve synchronization is to have a common clock for both the transmitter and the receiver, as the two can never, in theory, get out of alignment. Many types of character code have evolved over the years, but now the almost universal standard is the ASCII code (American Standard Code for Information Interchange, also known as ISO 646). The advantages of serial transmission arise from cost and flexibility. For a true distributed control system, one needs a method whereby several PLCs or computers can be linked together to allow communication to freely take place between any members of the system. The interconnection between different machines can bring even more problems than linking two “RS232-compatible devices”. Common problems are different baud rates, flow control, routing, and protocols. The bit corresponding to “motor run” that is set inside PLCB will not be cleared by link failure and PLCA will be unable to stop the motor. Data at the transmitter is converted into light pulses that are conveyed down the fiber optic cable and detected by a photosensor at the receiver. Fiber optic cable should always be well protected with conduit or robust trunking to minimize damage. Most fiber optic links use high-power optical sources, sometimes lasers.

Abstract: In this artical, a new method of serial communication using special purpose level conversion chip MAX232 between PC and MCS 51 single chip microcontroller is introduced. The selection of the communication mode, setting of the baud rate of the 89C51 and its setting of communication are stated in detail. Through the analysis of the hardware and software design of the interface circuit, its practicability is presented.

Abstract: This paper presents and compares several techniques that detect the symbol rate of unknown received signal. Symbol rate is detected from the power spectral density of the circuits such as the delay and multiplier circuit, the square law circuit, and analytic signal, etc. As a result of discrete Fourier transform of the output signals of these circuits, a lot of spectral lines and some peaks appear in frequency domain and the position of first peak is corresponding to the symbol rate. If a spectral line on the frequency that is not located in symbol rate is larger than the first peak, the symbol rate is erroneously detected. Thus, the ratio between the value of first peak and the highest side spectral line is used for the measure of the performance of symbol rate detector. For the MPSK modulation, the analytic signal method shows better performance than the delay and multiplier and square law circuits when the received signal power is lager than -20dB. It is also noted that the delay and multiplier circuit is not able to detect the symbol rate for the QAM modulation.