Ultra-wideband Signal Generation Research Articles

A METHOD OF PROTECTING INFORMATION IN CYBER-PHYSICAL SPACE

The subject of the study is the processes of ensuring the reliability and security of information in cyber-physical space. The objective is to develop recommendations for the implementation of a method of information security in cyber-physical space. The development is based on the technology of ultra-wideband signals circulating in wireless communication channels. The task is to ensure the stable and reliable operation of the airborne wireless mobile communication network, which is the main component of cyberspace and its most vulnerable link to destructive influences. Methods used: methods of analytical modelling and time-position pulse coding. The following results were obtained. It is shown that in order to ensure high quality of wireless network operation, it is necessary to expand its bandwidth, which is limited by the physical resource of the radio frequency spectrum. It is proposed to overcome this contradiction by applying the technology of ultra-wideband signals, the base of which is much larger than one. In this case, the information signal is emitted without a carrier frequency simultaneously in the entire frequency band, provided that the signal level is lower than the noise level. The method of positional-time coding is used, in which each information bit is encoded by hundreds of ultra-short chip pulses arriving in a certain sequence. In such wireless communication systems, the use of autocorrelation reception of modulated ultra-wideband signals is proposed. A comparative analysis has shown that the wireless network with the best reliability and noise immunity is the one where the time separation of the reference and information signals is applied. During the first half of the bit interval, the switch closes the transmitter output directly to the ultra-wideband signal generator, forming a reference signal. In the middle of the bit interval, the switcher switches the output to one of two possible positions depending on the signal "zero" or "one", forming the information part of the signal. Conclusions. Systems with autocorrelation reception and separate transmission of reference and information signals provide a high level of structural

Generation of optical UWB signals based on combined bright solitons

We investigate the generation of ultra-wide band (UWB) signal in all optical domain based on combined bright solitons by numerical method. The combined solitons with ultra-wideband characteristics can be obtained by multiple bright solitons. The power spectrum can be modulated by pulse interval, pulse width and phase difference of combined bright solitons to satisfy with the Federal Communications Commission (FCC) spectrum mask. Meanwhile, the transmissions of combined bright solitons in single-mode fibers are discussed. The fiber loss and dispersion effects have the influence on the transmissions of combined bright solitons. In order to eliminate dispersion effects, the stable transmission of signals in dispersion decreasing fibers is proposed.

A Compact, Ultra-Wideband, Transformer-Based Quadrature Signal Generation Network in 45 nm CMOS SOI for 5G Applications

In this article, we present an ultra-wideband, fully-differential quadrature signal generation network for 5G applications. The ultra-wideband network is composed of a passive balun and cascaded transformer-based quadrature hybrid. Passive balun converts a single-ended signal to differential with minimum insertion loss, and transformer-based quadrature hybrids are cascaded to suppress I/Q imbalance over an ultra-wide bandwidth. The coupling coefficient of the transformer-based quadrature hybrid is enhanced by adopting vertically stacked multiturn transformer topology to extend operation bandwidth and reduce passive loss and chip area. A novel layout and signal routings are proposed to reduce passive loss, undesired magnetic coupling and I/Q imbalance, making meander lines for phase matching unnecessary. The proposed ultra-wideband quadrature signal generation network is designed in GlobalFoundries 45 nm CMOS SOI process with a core area of 845 μm × 495 μm. The output I/Q magnitude mismatch is less than 0.5 dB from 16 to 60 GHz, and phase mismatch is less than 2° from 16.5 to 54.7 GHz. The input return loss is lower than −10 dB from 22 to 45 GHz, and signal loss varies from 5.74 to 7.4 dB (including 1:2 power splitting and loss from passive balun). The effective image rejection ratio (IRR) is calculated based on I/Q mismatch and is higher than 40 dB from 21.5 to 53.5 GHz.

Experimental Generation of Reconfigurable Ultra-Wideband Signal Based on the Pulse Difference by Using Optical Polarization Synthesis

A reconfigurable optical ultra-wideband (UWB) pulse generation scheme based on the pulse difference by using polarization synthesis is proposed and demonstrated experimentally. The Gaussian pulses with an appropriate time delay are modulated via the two sub-MZMs of the DPol-MZM, and the optically carried signals are combined via orthogonal polarization multiplexing, avoiding the optical interference. By setting the DC bias voltages of the sub-MZMs and the time delay, a pair of polarity-reversed Gaussian monocycle, doublet, triplet and quadruplet signals are generated with the central frequency of 3.37, 4.79, 4.5, 5.05 GHz and the fractional bandwidths of 166%, 129%, 124%, 89% accordingly. The signals of pulse shape modulation, binary phase shift keying modulation and on-off keying modulation are generated with the experimental system.

Ultra-wideband signal generation and fusion algorithm for high-resolution terahertz FMCW radar imaging.

The terahertz frequency modulated continuous wave (THz FMCW) imaging has proved to be a novel nondestructive testing (NDT) technology for non-metal materials, and the large bandwidth is usually required to meet high range resolution demands in many applications such as multilayer sample under test (SUT). However, broadband THz hardware is difficult to design. In this paper, an ultra-wideband THz FMCW generation method is proposed, which provides frequency modulation bandwidths of up to 386 GHz by time-division multiplexing. Furthermore, an ultra-wideband signal fusion algorithm (USFA) is also proposed and significantly improves the range resolution to 0.46 mm in air. Results from the artificially constructed multilayer structure demonstrate the superiority and effectiveness of our method quantitatively.

Photonic Generation of Highly-Linear Ultra-Wideband Stepped-Frequency Microwave Signals With Up to 6·106 Time-Bandwidth Product

A photonic-based technique for the generation of highly-linear ultra-wideband stepped-frequency microwave signals with large time-bandwidth product is proposed and experimentally demonstrated. The double-gated recirculating frequency-shifting optical fiber loop enables the frequency of the generated microwave signal to hop step-wisely at exact increment. The generation of signals with up to 20 GHz bandwidth and ∼300 μs temporal duration, corresponding to a time-bandwidth product of 6·10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> , is achieved by the proof-of-concept system with electronics of only up to 80 MHz bandwidth. Nonlinearity of less than 10− <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> and high intra- and inter-period coherence are also experimentally validated. This work provides applications such as high resolution radar with a promising low-cost solution for generating large time-bandwidth product waveforms with frequency scalability and extreme linearity.

Broadband random optoelectronic oscillator

Random scattering of light in transmission media has attracted a great deal of attention in the field of photonics over the past few decades. An optoelectronic oscillator (OEO) is a microwave photonic system offering unbeatable features for the generation of microwave oscillations with ultra-low phase noise. Here, we combine the unique features of random scattering and OEO technologies by proposing an OEO structure based on random distributed feedback. Thanks to the random distribution of Rayleigh scattering caused by inhomogeneities within the glass structure of the fiber, we demonstrate the generation of ultra-wideband (up to 40 GHz from DC) random microwave signals in an open cavity OEO. The generated signals enjoy random characteristics, and their frequencies are not limited by a fixed cavity length figure. The proposed device has potential in many fields such as random bit generation, radar systems, electronic interference and countermeasures, and telecommunications.

A full duplex ultrawideband over free‐space optics architecture based on polarization multiplexing and wavelength reuse

AbstractThis article demonstrates the integration of fiber optics with free space optics for the transmission of ultrawideband signals at a data rate of 2 Gbps. The fiber‐based components enable all‐optical generation of ultrawideband signals. The free space optical link allows bandwidth flexibility along with reduced installation costs. The proposed architecture employs polarization multiplexing and carrier reuse in order to make the radio access units simple and cost‐efficient. The free space optical link is modeled using the log‐normal (LN) channel model. Bit‐error‐rate (BER) measurements demonstrate that the proposed link is suitable for the transmission of high throughput ultrawideband signals.

Ultra-wideband doublet signal generation with tunable notch band based on delay-line filter

ABSTRACT A novel and simple scheme to generate Ultra-wideband (UWB) doublet signal with tunable notch band based on a tunable delay-line filter is presented. The first-order differentiation is realized by a dual-drive Mach–Zehnder modulator (DD-MZM), which differentiates the Gaussian pulses to the monocycle pulses. Subsequently, the UWB monocycle pulses are transmitted to an optical delay-line filter implemented by a balanced photo-detector and a tunable delay line for both differentiation and photodetection. Consequently, the desired UWB doublet signal can be obtained with a 10-dB bandwidth of 8.75 GHz. Besides, the polarity reversibility of the generated doublet signal is demonstrated by changing the bias voltage of the DD-MZM. Moreover, the desired notch can be introduced in the generated frequency spectrum to eliminate the interference between the existing narrowband systems and the UWB systems. And the tunability of the band-notched position is implemented by simply adjusting the delay time of the delay-line filter. The feasibility of the presented scheme is investigated by mathematical models and simulations.

UWB quadruplet signal generation based on a DP-QPSK modulator and a delay-line filter.

A photonic ultra-wideband (UWB) quadruplet signal generation based on a dual-polarization quadrature phase shift keying (DP-QPSK) modulator is presented. A Gaussian sequence is split into four parts and input to the four driving ports of the DP-QPSK. Through polarization rotation and polarization combination, a pair of polarization-orthogonal, polarity-reversed doublet signals are generated from the output of the DP-QPSK modulator. Subsequently, they are injected into a balanced photodetector (BPD) for further differentiation. After the heterodyne detection, a UWB quadruplet signal can be obtained. In this system, four electrical amplifiers are incorporated into the four electrical driving paths to adjust the modulation indices of the DP-QPSK. To attain the optimal spectral power efficiency (SPE), a relationship among the SPE, pulse width, delay time, and the two main modulation indices is created. Consequently, the optimal point is found with an SPE of 53.46%. Then, several impairments brought by the nonideal devices are considered in the simulation system. The distortion caused by impairments is compensated by properly adjusting the devices. The generated spectrum has a SPE of 53.38% and efficiently complies with the Federal Communications Commission (FCC) mask without any low-frequency components exceeding the FCC mask. In addition, on-off keying and pulse position modulation are realized in the system.

Photonic microwave generation in the X- and K-band using integrated soliton microcombs

Microwave photonic technologies, which upshift the carrier into the optical domain to facilitate the generation and processing of ultrawide-band electronic signals at vastly reduced fractional bandwidths, have the potential to achieve superior performance compared to conventional electronics for targeted functions. For microwave photonic applications such as filters, coherent radars, subnoise detection, optical communications and low-noise microwave generation, frequency combs are key building blocks. By virtue of soliton microcombs, frequency combs can now be built using CMOS compatible photonic integrated circuits, operated with low power and noise, and have already been employed in system-level demonstrations. Yet, currently developed photonic integrated microcombs all operate with repetition rates significantly beyond those that conventional electronics can detect and process, compounding their use in microwave photonics. Here we demonstrate integrated soliton microcombs operating in two widely employed microwave bands, X- and K-band. These devices can produce more than 300 comb lines within the 3-dB-bandwidth, and generate microwave signals featuring phase noise levels below 105 dBc/Hz (140 dBc/Hz) at 10 kHz (1 MHz) offset frequency, comparable to modern electronic microwave synthesizers. In addition, the soliton pulse stream can be injection-locked to a microwave signal, enabling actuator-free repetition rate stabilization, tuning and microwave spectral purification, at power levels compatible with silicon-based lasers (<150 mW). Our results establish photonic integrated soliton microcombs as viable integrated low-noise microwave synthesizers. Further, the low repetition rates are critical for future dense WDM channel generation schemes, and can significantly reduce the system complexity of photonic integrated frequency synthesizers and atomic clocks.

基于扫频激光器的超宽带线性调频信号产生传输研究

基于扫频激光器的超宽带线性调频信号产生传输研究

A 2.12-V $V_{pp}~11.67$ -pJ/pulse Fully Integrated UWB Pulse Generator in 65-nm CMOS Technology

This paper presents a high-voltage ultra-wideband (UWB) pulse generator. Shifting the UWB signal synthesis to digital domain using two consecutive trapezoidal waves, the design requires only a simple low-loss passive filter to conform to UWB spectrum regulations. A power amplifier stage is added to boost the output voltage above the supply voltage limit. To verify the design concept, the generator is designed in TSMC CMOS 65 nm technology with 1 V supply voltage occupying a die size of 0.34 mm2. The UWB generator achieves an efficiency of 21% while the total energy consumption is 11.67 pJ/pulse. On-chip measurement is in good agreement with the simulation and shows output peak-to-peak amplitude of 2.12 V after adding the cable and probe losses to the measured 1.62 V peak-to-peak voltage. The proposed UWB signal generator achieves the highest peak-to-peak to supply voltage ratio among the UWB signal generators reported to the date.

All-optical generation and transmission of multiple ultrawideband signals over free space optical link

Ultrawideband (UWB) signals have low allowable transmission powers. To enhance the coverage and capacity of UWB signals, a cost-efficient solution for the access network has been proposed and simulated. The access network is based on gamma–gamma free-space optical channel model, which is employed between the central unit and the four different carrier-free radio access units (RAUs). All-optical generation and transmission of UWB signals at a rate of 1.5 Gbps to each RAU are demonstrated. Bit error rate results are obtained to observe the performance of the UWB signals received at the mobile stations. The proposed architecture requires minimum deployment cost and gives acceptable bit error rate results.

All-optical regenerative technique for width-tunable ultra-wideband signal generation

We demonstrate all-optical generation of width-tunable mono-cycle pulses for ultra-wideband communication. It has been shown that the width of the mono-cycle pulses can be tuned dynamically by simply varying the power of the optical signal. We also investigate the regenerative property of the nonlinear medium-based technique for the generation of mono-cycle pulses. For the purpose of comparison, ultra-wideband mono-cycle pulses are also generated through the optical delay line-based technique. It has been demonstrated through numerical simulations that the nonlinear medium-based technique is highly resilient to amplified spontaneous emission noise that is induced over the optical signal. Furthermore, we have shown that the highly nonlinear fiber-based nonlinear medium performs better than the semiconductor optical amplifier-based medium. Bit error rate measurements are taken for different values of optical signal-to-noise ratios in order to elaborate our work.

Photonic generation of millimeter-wave ultra-wideband monocycle signal using up-conversion based on stimulated Brillouin scattering effect

We propose a novel scheme for photonic generation of millimeter-wave (MMW) ultra-wideband monocycle signal free of strong local oscillation (LO) and low-frequency component. A theory and a mathematical model are built to investigate the proposed scheme. Firstly, a differentiator is implemented using a dual-drive Mach–Zehnder modulator to attain monocycle pulses by differentiating a series of Gauss pulses. Subsequently, a dual-parallel Mach–Zehnder modulator and stimulated Brillouin scattering effect are employed to realize single-sideband modulation for up-converting the monocycle pulses to the MMW band. In the calculation, the generated signal is centered at 26 GHz with 10-dB bandwidth of 7 GHz and its power efficiency is about 50.08%. In addition, on–off keying modulation, amplitude modulation (PAM) and pulse position modulation monocycle pulses are generated. The spectrum of the generated signal meets with the FCC mask efficiently, so this technique has a potential application in MMW radar communication systems.

Photonic Generation of Ultra-Wideband Signal by Truncating a Continuous Wave into a Pulse

We propose and demonstrate a background-free millimeter-wave (MMW) ultra-wideband (UWB) signal generator using a dual-polarization dual-parallel Mach–Zehnder modulator. The MMW-UWB signal is generated by truncating a continuous-wave (CW) radio-frequency (RF) signal into an RF pulse. The upper dual-parallel Mach–Zehnder modulator (DPMZM1) is properly set to act as a phase modulator, while the lower DPMZM2 is well biased to generate a carrier-suppressed double-sideband (CS-DSB) modulated signal. By shifting the phase of the optical carrier through DPMZM1, a CW RF signal is truncated into a pulse one in a photodetector (PD). The baseband frequency components and local oscillator signal are well suppressed, since the optical power sent to the PD is constant. Moreover, there is no optical or electrical filters involved, which ensures a broad operation bandwidth and wide tunability. The proposed scheme is theoretically analyzed and experimentally verified. The generated background-free UWB signal at an RF carrier frequency of 26 GHz meets well the Federal Communications Commission spectral mask for outdoor UWB systems.

Photonic millimeter-wave ultrawideband signal generation using frequency upconversion based on the stimulated Brillouin scattering effect

We present a novel and simple scheme for photonic generation of a millimeter-wave ultrawideband (UWB) signal free of low-frequency components that is implemented by using a stimulated Brillouin scattering (SBS)-based frequency-doubling method. A dual-parallel Mach-Zehnder modulator is incorporated to generate appropriate optical sidebands and an optical carrier carrying the UWB signal. Then the single-sideband modulation is realized based on the successive SBS frequency shifting process. Eventually, a UWB signal is upconverted to twice the frequency of the radio frequency signal. To vindicate the feasibility of the proposed scheme, an experiment is carried out, and it turns out that a UWB signal with a bandwidth of 7GHz is upconverted to 21.75GHz. The spectrum of the generated signal meets well with the Federal Communications Commission mask.

A solid-state microwave-range self-oscillating chaotic system with a simplified structure

A solid-state self-oscillating system that provides generation of ultra-wideband chaotic signals in the microwave range has been proposed, implemented, and studied. The system has a simple structure comprising an active element (bipolar transistor) and a single reactive element (inductance). An experimental study of bifurcation phenomena and typical oscillation modes in the system has been carried out. The energy efficiency of the system and the possibility of its implementation in the form of a chip structure are analyzed.

Photonic generation of background-free millimeter-wave ultra-wideband signals (Invited Paper)

We review the recent progress of photonic generation of millimeter wave (MMW)-ultra-wideband (UWB) signals. To fully satisfy the standard defined by the Federal Communications Commission (FCC), the baseband signal (background signal) and the residual local oscillator (LO) signal should be well controlled. We discuss several schemes in this work for generating background-free MMW-UWB signals that are fully compliant with the FCC requirement.