Binary Shift Research Articles

Chaotic Binary Modulation Excitation Sequences for Multichannel Ultrasonic Ranging System

A crosstalk elimination method by using the optimal binary excitation sequences modulated with chaotic codes, which includes chaotic binary amplitude shift keying (c-BASK), chaotic binary phase shift keying (c-BPSK) and chaotic binary frequency shift keying (c-BFSK), is proposed in this paper. The selection of the optimal chaotic initial values with the best echo correlation characteristics is realized by adopting a genetic algorithm. A square wave is used as the carrier of the chaotic binary modulation methods in order to reduce hardware cost. However, it could suffer from the decreased energy efficiency caused by mismatching spectrum with ultrasonic ranging system. The parameters of the chaotic binary modulation methods are configured to make their central frequency and bandwidth matched with that of the ultrasonic ranging system very well. Experiments have been conducted using an ultrasonic ranging system that consists of eight-channel SensComp 600 series instrument-grade electrostatic sensors excited with chaotic binary sequences. Experimental results show that the c-BFSK outperforms the c-BASK and c-BPSK in terms of the energy efficiency, e.g., 0.3508 vs. 0.3365 and 0.3279 , respectively. And the optimized c-BFSK sequence also has the best echo correlation characteristics among the chaotic binary modulation sequences. http://dx.doi.org/10.11591/telkomnika.v12i12.4640

A Composite Shadowed Fading Model Based on the McKay Distribution and Meijer G Functions

The McKay density function has been cited in the study of wireless channels in connection with the analysis of diversity. It is also a forerunner of the $$\upeta $$?-$$\upmu $$μ and $$\upeta $$?-$$\uplambda $$?-$$\upmu $$μ distributions in wireless channels. Starting with a physical description of fading in terms of clustering and using the existing results from the original work of Nakagami, the probability density function of the signal-to-noise ratio has been shown to match the three parameter McKay distribution. It is demonstrated that the McKay density also allows for the modeling of wireless channels exhibiting fading levels far worse than what is seen in Nakagami channels, allowing the amount of fading to vary from 0 to $$\infty $$?. The shadowing in wireless channels is then incorporated in the model using the cascading concept to describe the shadowing. The error rates in such a McKay---Meijer G model are studied using the example of a coherent binary shift keying modem. With the availability of closed form expressions for the density, cumulative distribution function, error rates and outage probabilities, the McKay---Meijer G model offers a very flexible means to study the performance of modems in composite shadowed fading channels.

Method and software for using m-sequences to characterize parallel components of higher-order visual tracking behavior in Drosophila.

A moving visual figure may contain first-order signals defined by variation in mean luminance, as well as second-order signals defined by constant mean luminance and variation in luminance envelope, or higher-order signals that cannot be estimated by taking higher moments of the luminance distribution. Separating these properties of a moving figure to experimentally probe the visual subsystems that encode them is technically challenging and has resulted in debated mechanisms of visual object detection by flies. Our prior work took a white noise systems identification approach using a commercially available electronic display system to characterize the spatial variation in the temporal dynamics of two distinct subsystems for first- and higher-order components of visual figure tracking. The method relied on the use of single pixel displacements of two visual stimuli according to two binary maximum length shift register sequences (m-sequences) and cross-correlation of each m-sequence with time-varying flight steering measurements. The resultant spatio-temporal action fields represent temporal impulse responses parameterized by the azimuthal location of the visual figure, one STAF for first-order and another for higher-order components of compound stimuli. Here we review m-sequence and reverse correlation procedures, then describe our application in detail, provide Matlab code, validate the STAFs, and demonstrate the utility and robustness of STAFs by predicting the results of other published experimental procedures. This method has demonstrated how two relatively modest innovations on classical white noise analysis—the inclusion of space as a way to organize response kernels and the use of linear decoupling to measure the response to two channels of visual information simultaneously—could substantially improve our basic understanding of visual processing in the fly.

Performance analysis of free-space optical systems employing binary polarization shift keying signaling over gamma-gamma channel with pointing errors

Free-space optics (FSO) has become one of the prominent solutions to the bandwidth limitation of radio frequency links. But, the FSO system performance is purely dependent on atmospheric conditions. Atmospheric turbulence, scintillation, and pointing errors are the major deteriorations in FSO communications. Multiple input multiple output (MIMO) or spatial diversity structure can improve the performance of the FSO system. The bit error rate (BER) performance of the MIMO FSO system employing binary polarization shift keying using optimal combining is analyzed. We have derived a closed form expression for the BER of the system, and the results are compared against the single input single output system.

Spin nano-oscillator-based wireless communication.

Spin–torque nano–oscillators (STNOs) have outstanding advantages of a high degree of compactness, high–frequency tunability, and good compatibility with the standard complementary metal–oxide–semiconductor process, which offer prospects for future wireless communication. There have as yet been no reports on wireless communication using STNOs, since the STNOs also have notable disadvantages such as lower output power and poorer spectral purity in comparison with those of LC voltage–controlled oscillators. Here we show that wireless communication is achieved by a proper choice of modulation scheme despite these drawbacks of STNOs. By adopting direct binary amplitude shift keying modulation and non–coherent demodulation, we demonstrate STNO–based wireless communication with 200–kbps data rate at a distance of 1 m between transmitter and receiver. It is shown, from the analysis of STNO noise, that the maximum data rate can be extended up to 1.48 Gbps with 1–ns turn–on time. For the fabricated STNO, the maximum data rate is 5 Mbps which is limited by the rise time measured in the total system. The result will provide a viable route to real microwave application of STNOs.

Analysis and Design of Network-Based Control Systems with Binary Modulation

Network-based control systems have been emerging technologies in control and computer communication fields over the past decade. This paper focuses on the analysis and design of network-based control systems with binary modulation. First, it is shown that different modulations can result in different delays which are inevitable in network-based control systems. The delay can be seen as constant delay when the transmission time is the main consideration. Second, channel noise can result in bit error while bit error is seen as active packet loss in this paper, in this context, the conditions of signal-to-noise ratio (SNR) for binary modulation that can guarantee the stability of systems are obtained according to the proposed algorithm. Third, the system with delay and noisy communication can be modeled as an asynchronous dynamic system (ADS); in addition, the stability is analyzed and controller is designed in terms of Lyapunov function and linear matrix inequality (LMI) scheme. Finally, without loss of generality, numerical simulation demonstrates the effectiveness of the proposed scheme and designed controller based on binary amplitude shift keying (2ASK) modulation.

Electromagnetic wave propagation of wireless capsule endoscopy in human body

Wireless capsule endoscopy (WCE) is a promising technique which has overcome some limitations of traditional diagnosing tools, such as the comfortlessness of the cables and the inability of examining small intestine section. However, this technique is still far from mature and asks for the feasible improvements. For example, the relatively low transmission data rate and the absence of the real-time localization information of the capsule are all important issues. The studies of them rely on the understanding of the electromagnetic wave propagation in human body. Investigation of performance of WCE communication system was carried out by studying electromagnetic (EM) wave propagation of the wireless capsule endoscopy transmission channel. Starting with a pair of antennas working in a human body mimic environment, the signal transmissions and attenuations were examined. The relationship between the signal attenuation and the capsule (transmitter) position, and direction was also evaluated. These results provide important information for real-time localization of the capsule. Moreover, the pair of antennas and the human body were treated as a transmission channel, on which the binary amplitude shift keying (BASK) modulation scheme was used. The relationship between the modulation scheme, data rate and bit error rate was also determined in the case of BASK. With the obtained studies, it make possible to provide valuable information for further studies on the selection of the modulation scheme and the real-time localization of the capsules.

Coherent Polarization Modulated Transmission through MIMO Atmospheric Optical Turbulence Channel

An optical signal suffers from irradiance and phase fluctuations when propagating through the free space optical (FSO) turbulence channel, thus resulting in the degradation of the bit error rate (BER) performance. The BER performance can be improved by adopting the multiple-input multiple-output (MIMO) scheme. In this paper, we propose a coherent binary polarization shift keying (BPOLSK) modulation scheme with MIMO employing maximum ratio combining and equal gain combining diversity techniques to mitigate the turbulence effect. The gamma-gamma statistical channel model is adopted for all the turbulence regimes. The BER performance for the proposed BPOLSK-MIMO FSO link is compared with the single-input single-output and ON-OFF-keying systems by means of computer simulation. The optical power gain is investigated and demonstrated under different turbulence regimes for a number of transmitters/receivers.

Binary amplitude shift keying based signal processing for brillouin optical correlation domain analysis

We propose and experimentally demonstrate a novel binary amplitude shift keying (BASK) based signal processing for Brillouin optical correlation domain analysis with better noise performance. To subtract the background noise substructure from the conventional, broadened Brillouin signal, this method utilizes the presence of two sidebands, leading to a fourfold improvement of the spatial resolution compared to that of an ordinary BOCDA system with the same modulation parameters.

Faster than expected escape for a class of fully chaotic maps

We investigate the dependence of the escape rate on the position of a hole placed in uniformly hyperbolic systems admitting a finite Markov partition. We derive an exact periodic orbit formula for finite size Markov holes which differs from other periodic expansions in the literature and can account for additional distortion to maps with piecewise constant expansion rate. Using asymptotic expansions in powers of hole size we show that for systems conjugate to the binary shift, the average escape rate is always larger than the expectation based on the hole size. Moreover, we show that in the small hole limit the difference between the two decays like a known constant times the square of the hole size. Finally, we relate this problem to the random choice of hole positions and we discuss possible extensions of our results to non-Markov holes as well as applications to leaky dynamical networks.

Diversity in cascaded N*Nakagami channels

Short term fading conditions that are worse than those existing in typical Nakagami channels can be modeled using the cascaded approach where the received signal-to-noise ratio is treated as the product of N identical or nonidentical random variables that are either dependent or independent. Cascaded channels also permit the modeling of fading seen in amplify and forward relaying channels as well as keyhole channels. The simplest of these models, referred to as the N*Nakagami model, assumes that the received signal to noise ratio is the product of N independent and identically distributed gamma variables. The fading mitigation achieved in such cascaded channels through diversity is studied in this work. Through analytical approach and simulation, the performance of wireless channels is examined for the selection combining, equal gain combining, generalized selection combining, and maximal ratio combining algorithms. Results demonstrate the existence of severe degradations in cascaded fading channels and the comparative usefulness of the various algorithms in improving the data transmission capabilities. Even though the analysis was undertaken for the case of a coherent binary shift keying modem, results can easily be extended to other modems.

Experimental investigation of polarisation modulated free space optical communication with direct detection in a turbulence channel

Binary polarisation shift keying (BPOLSK) has been proposed to mitigate the atmospheric turbulence-induced fading in free space optical (FSO) communication systems. In this study, the Q-factors obtained for the BPOLSK-FSO system are verified in conjunction with theoretical results to confirm the validity of the proposed scheme. The analytical bit error rate (BER) for the BPOLSK and non-return-to-zero on–off keying (NRZ-OOK) schemes are presented. The authors show that the BPOLSK scheme with direct detection offers improved BER performances compared to NRZ-OOK in the presence of weak turbulence, which is inferred from the experimental Q-factor and theoretical BER. For a turbulence variance σ21 of 0.003 and the transmitted optical power of −16.8 dBm, values for Q-factor are ∼11 and ∼8.5 for BPOLSK and NRZ-OOK schemes, respectively. The authors show that the predicted signal-to-noise ratio (SNR) for BPOLSK and NRZ-OOK schemes are ∼13.5 and ∼15 dB, respectively, for a BER of 10−6 and σ21 of 0.01. When σ21 increases to 0.1, ∼8 dB lower values of SNR is required for BPOLSK compared with NRZ-OOK.

FT-IR study on interactions between medroxyprogesterone acetate and solvent in CHCl3/cyclo-C6H12 and CCl4/cyclo-C6H12 binary solvent systems

The intermolecular interactions between medroxyprogesterone acetate (MPA) and CHCl3 and CCl4 solvent in CHCl3/cyclo-C6H12 and CCl4/cyclo-C6H12 binary solvent systems have been studied by Fourier transform infrared spectroscopy (FT-IR). The experimental results showed that there are hydrogen bonding interactions between oxygen atoms of all carbonyl groups in MPA and hydrogen atom of CHCl3 so as to form 1:3 complex of MPA with CHCl3 and produce three new absorption bands at 1728.9–1736.1, 1712.7–1717.4 and 1661.9–1673.8cm−1, respectively. And, 1:1 complex of MPA with CCl4 is formed in CCl4/cyclo-C6H12 binary solvent as a result of hydrogen bonding interaction between C3 carbonyl group and empty d-orbital in chlorine atom of CCl4 leading to producing new absorption band at 1673.2–1674.2cm−1. However, all free carbonyl and associated carbonyl stretching vibrations of MPA in CHCl3/cyclo-C6H12 and CCl4/cyclo-C6H12 binary solvent systems shift to lower wavenumbers with the increasing of volume fraction of CHCl3 and CCl4 in binary solvent systems owing to the dipole–dipole interaction and the dipole–induced dipole interaction between MPA and solvents.

Quadrature Amplitude Modulated Backscatter in Passive and Semipassive UHF RFID Systems

Passive and semipassive UHF RF identification (RFID) systems have traditionally been designed using scalar-valued differential radar cross section (DRCS) methods to model the backscattered signal from the tag. This paper argues that scalar-valued DRCS analysis is unnecessarily limiting because of the inherent coherence of the backscatter link and the complex-valued nature of load-dependent antenna-mode scattering from an RFID tag. Considering modulated backscatter in terms of complex-valued scattered fields opens the possibility of quadrature modulation of the backscatter channel. When compared with binary amplitude shift keying (ASK) or phase shift keying (PSK) based RFID systems, which transmit 1 bit of data per symbol period, and thus 1 bit per on-chip clock oscillator period, tags employing vector backscatter modulation can transmit more than 1 bit per symbol period. This increases the data rate for a given on-chip symbol clock rate leading to reduced on-chip power consumption and extended read range. Alternatively, tags employing an M-ary modulator can achieve log2 M higher data throughput at essentially the same dc power consumption as a tag employing binary ASK or PSK. In contrast to the binary ASK or PSK backscatter modulation employed by passive and semipassive UHF RFID tags, such as tags compliant with the widely used ISO18000-6c standard, this paper explores a novel CMOS-compatible method for generating M-ary quadrature amplitude modulated (QAM) backscatter modulation. A new method is presented for designing an inductorless M-ary QAM backscatter modulator using only an array of switched resistances and capacitances. Device-level simulation and measurements of a four-state phase shift keying (4-PSK)/four-state quadrature amplitude modulated (4-QAM) modulator are provided for a semipassive (battery-assisted) tag operating in the 850-950-MHz band. This first prototype modulator transmits 4-PSK/4-QAM at a symbol rate of 200 kHz and a bit rate of 400 kb/s at a static power dissipation of only 115 nW.

A study of decimal left shifters for binary numbers

The importance of decimal floating-point (DFP) arithmetic has been growing in the last years, and specifications for it are included in the revised IEEE 754 Standard for Floating-Point Arithmetic (IEEE 754-2008). IEEE 754-2008 specifies a binary encoding for decimal significands, in which the significands of DFP numbers are represented as unsigned binary integers. For this representation, which is commonly referred to as the binary integer decimal (BID) encoding, fast decimal left shifting of a binary number is useful for operand alignment, normalization, overflow avoidance, and quantize operations. A decimal left shift of an unsigned binary integer, I, by S digit positions corresponds to multiplying I by 10S. This paper presents the theory and design of decimal left shifters for binary numbers. The designs perform decimal left shifting using optimized constant multiplications by selected powers of ten. We propose and analyze different combinational and sequential decimal left shifter architectures for binary numbers. The designs are compared to one another in terms of area and delay using both theoretical estimates and synthesis results for 16-digit (54-bit) binary inputs and 4-bit shift amounts. The results indicate that an optimized radix-2 decimal shifter implementing partial shifters in carry-save format has 80% less area and 68% less delay than a lookup table followed by a binary multiplier to compute I×10S, when both designs are optimized for delay. When both designs are optimized for area, the radix-2 decimal shifter has 89% less area and 31% less delay.

Optimized Pseudorandom BASK Emission Sequences for Ultrasonic Multi-Life Location System

This paper addresses the performance of pseudorandom Binary Amplitude Shift Keying (BASK) emission sequences for an ultrasonic multi-life location system in rescue robot. To improve the performance of multi-life location system, the BASK modulation were used to construct the spread spectrum emission sequences for ultrasonic sensors. Correlation technique in the receiving circuit was used to de-spread. Good correlation characteristics, i.e., sharp autocorrelation and flat cross-correlation, can help eliminate crosstalk between multichannel ultrasonic sensors. To improve the echo signal correlation effect, genetic algorithm was applied to optimize pseudorandom m sequences. In simulated post-earthquake environment, experimental verification of ultrasonic multi-life location system consisting of eight-channel SensComp 600 series electrostatic sensors with optimized BASK emission sequences was carried out. The experimental results demonstrate that the ultrasonic multi-life location system with the proposed method can realize multi-life location simultaneously.

Coherent optical binary polarisation shift keying heterodyne system in the free-space optical turbulence channel

In this study, analytical and simulation results for the bit error rate (BER) performance and fading penalty of a coherent optical binary polarisation shift keying (2PolSK) heterodyne system adopted for a free-space optical communication link modelled as the log-normal and the negative exponential atmospheric turbulence channels are presented. The conditional and unconditional BER expressions are derived, demonstrating the comprehensive similarity between the 2PolSK and the binary frequency shift keying schemes with regard to the system sensitivity. The power penalty owing to the non-ideal polarisation beam splitter is also analysed. The receiver sensitivity employing 2PolSK is compared with other modulation schemes in the presence of turbulence and the phase noise. The results show that 2PolSK offers improved signal-to-noise ratio performance compared to the binary amplitude shift keying.

Two results on stable rapidly oscillating periodic solutions of delay differential equations

In 1999 Ivanov and Losson [A.F. Ivanov and J. Losson, Stable rapidly oscillating solutions in delay differential equations with negative feedback, Differ. Int. Eqns 12 (1999), pp. 811–832] presented a computer assisted proof that a particular delay differential equation (with negative feedback) admits a stable rapidly oscillating periodic solution (ROPS). In this article the delay equation of Ivanov and Losson is embedded in a five-parametric class of differential equations. Conditions on the parameters are given such that the delay equation admits a stable ROPS. Moreover, it is shown that for odd n > 1 the delay equation admits a stable ROPS with n humps per unit time if the parameters satisfy some explicitly given conditions. The delay equation of Ivanov and Losson satisfies all conditions on the five parameters. This gives an analytic proof and a considerable generalization of the result of Ivanov and Losson. The conditions on the parameters are believed to be sharp in a certain sense. The second result proves part of a conjecture in Stoffer [D. Stoffer, Delay equations with rapidly oscillating stable periodic solutions, J. Dyn. Differ. Eqns 20(1) (2008), pp. 201–238]. For a class of stiff delay differential equations with piecewise constant nonlinearity (positive or negative feedback) and for every n the following holds: if the stiffness parameter is sufficiently large then there are 2a(n) essentially different stable ROPSs with n humps per time unit. a(n) is the number of essentially different binary n-stage shift register sequences.

Fast algorithm for quadratic aberration model in optical lithography based on cross triple correlation

The quadratic aberration model used in optical lithography is a natural extension of the linear model by taking into account interactions among individual Zernike coefficients. Although the model has been tested and verified in many applications, the effects of Zernike coefficients under partially coherent imaging are usually obtained by extensive experiments due to the complexity of the model expression. In this paper, a generalized cross triple correlation (CTC) is introduced and a fast algorithm to simulate the quadratic aberration model is developed. Simulations were performed by the proposed CTC-based algorithm with different input Zernike aberrations for binary and phase shift masks with multiple pitches and orientations, which demonstrate that the proposed approach is not only accurate but also efficient for revealing the influence of different Zernike orders on aerial image intensity distributions under partially coherent illumination.

A NOVEL DIFFERENTIAL CHAOS SHIFT KEYING MODULATION SCHEME

In binary Differential Chaos Shift Keying (DCSK), the reference and information bearing chaotic wavelets are transmitted in two consecutive time slots. This TDMA approach provides two independent channels for the transmission of reference and information bearing wavelets but requires a delay component both in the modulator and demodulator circuits, furthermore, it halves the data attainable data rate. The wideband Radio Frequency (RF) delay lines at receiver are extremely difficult to implement with CMOS technology, therefore, the DCSK modulation cannot be exploited in many applications, such as ultra-wideband. To avoid the use of wideband RF delay lines at receiver, an alternative solution is proposed here where both the reference and information bearing wavelets are sent in the same time slot. The two wavelets are separated by Walsh codes instead of time delay. The new modulator and demodulator configurations are given, analytical expressions for the Bit Error Rate (BER) are derived and the derived BER expressions are verified by computer simulations over Additive White Gaussian Noise (AWGN) and multipath Rayleigh fading channels.