Amplitude Shift Keying Signal Research Articles

ВВЕДЕНИЕ В ТЕОРИЮ СТАТИСТИЧЕСКОЙ МОДУЛЯЦИИ

Using new knowledge and models of known signals with amplitude shift keying (ASK), build a statistical theory of designing promising modems for information and control systems. The statistical theory is based on the characteristic function of A. Lyapunov of a random signal. It is proposed to consider the characteristic function of a non-deterministic signal with ASK, which simultaneously with the amplitude of the oscillation is modulated by a telegraph message. Taking into account this phenomenon, it was decided to further investigate the ASK signal from the standpoint of the so-called statistical shift keying (SSK), since the advantages of the new modulation method according to the forecast will significantly increase the performance of the proposed modem. The old demodulator is removed in the ASK modem and a patented demodulator is installed for receiving SSK signals using estimates of the real and imaginary parts of the Lyapunov characteristic function. The analysis of the energy performance and noise immunity of the modernized modem is made. As a result of the use of the first discovered property of the Lyapunov characteristic function, the noise immunity of a digital system with amplitude shift keying is increased by ten orders of magnitude by including a promising modem in its composition, and an energy gain of 10 dB compared to QPSK or 13 dB compared to ASK is obtained. Practical relevance: Replacing old ASK signal modems with new SSK signal modems will increase the quality of digital systems many times and make them competitive with other systems, including QPSK digital systems.

Bidirectional Bluetooth Backscatter with Edges

Bidirectional links are widely adopted in many active radios to provide efficient data exchanges, e.g., WiFi and Bluetooth. However, they are underexplored for general-purpose backscatter communications. The downlinks of state-of-the-art Bluetooth backscatter systems are based on packet length modulation, which is inefficient and unreliable. In this paper, we propose BiBlue, a bidirectional Bluetooth backscatter system that uses an edge server to enable fast and reliable downlinks. Specifically, our edge server acts like a bridge that can translate commercial Bluetooth signals to Amplitude Shift Keying (ASK) signals. In addition, we design a reliable edge-to-tag link that adaptively decodes ASK signal under variance. Finally, we propose a low-power uplink design that enables connection-based bidirectional communication with commodity devices. We prototype BiBlue using FPGA and Software Defined Radio (SDR). Extensive experimental results demonstrate that BiBlue achieves more than 62x downlink throughput gains over FreeRider and meanwhile supports an 80 cm communication range of edge-to-tag with BER at around 1%.

Design and implementation of reconfigurable ASK and FSK modulation and demodulation algorithm on FPGA (Field Programmable Gate Array)

Our modern world is completely driven by our ability to communicate all over the world with great precision, accuracy, and the least amount of time possible. Communication systems are used vastly in our worlds such as radar, aerospace, naval/maritime communication, underwater communication, mobile communication, or even in outer space such as satellite communication or space missions. Different communication system needs different types of modulation techniques. Design and implementation of reconfigurable modulators on cyclone-II FPGA (Field-programmable gate array) are proposed in this paper, wherein the type of modulations and demodulation can be dynamically reconfigured on the fly based on the requirement at any particular instance. The demodulator is intelligent enough to demodulate any modulated signal. FPGA or Field Programmable Gate Array is a computing device that can be programmed like CPU (Central Processing Unit) but fasted than CPU in parallel processing and DSP (Digital Signal Processing) related tasks. Consisting method of FPGA-based modulation does not support multiple modulation techniques at the same time and is not fast as they used Simulink-based simulation. This study has proposed FPGA based alternative to that, which can embody all the modulation techniques at once, making it way more versatile, cost-effective, and easy to use and test. The process begins with designing an algorithm. Then this algorithm has to be simulated. The algorithm is designed for both modulation and demodulation. In the modulation part, it is just simple logic to create different phrases and different frequencies of sinusoidal waves. But in demodulation, based on the frequency it can detect ASK (Amplitude Shift Keying) or FSK (Frequency Shift Keying) signal all by itself. Depending on the period of the signal, the algorithm can decide whether it is an ASK or FSK signal. After deciding it is an ASK of FSK signal, it starts to demodulate the signal. The outcome is, this FPGA-based modulator and demodulator are cheap, easy to configure, and can demodulate any type of demodulated signal. As it is reconfigurable, it's easy to deploy in any situation.

An ASK Data Demodulator Circuit for Implantable Medical Devices Supporting a Minimum Modulation Depth of 0.034.

Amplitude shift keying (ASK) data demodulation method has been widely used for simultaneous wireless data and power transfer in implantable medical devices (IMDs). Small amplitude modulation depth (MD) is usually preferred as it helps promote energy harvesting efficiency. This paper presents an ASK data demodulator that has good immunity to disturbances and can demodulate ultra-low MD ASK signal. A three-stage amplifying structure (3SAS) is proposed, in which the common-mode level of each amplifier is set between the high and low levels of its input signal envelope to prevent amplifier gain saturation and maximize the amplification of the envelope difference. Two envelope detectors (EDs) are used before and after the 3SAS respectively. The first one is to obtain a coarse envelope for 3SAS input and the second one is to further suppress the residual carrier interference and get a fine envelope. The proposed demodulator is implemented in 0.18-μm high-voltage Bipolar-CMOS-DMOS (BCD) technology. The detectable MD is measured as low as 0.034%, showing that the proposed demodulator can work smoothly and robustly in some extreme cases of simultaneous data and power transferring.Clinical Relevance- The ASK data demodulator proposed in this paper supports ultra-low modulation depth. This reduces the bit error rate of the data link and keeps a highly power conversion efficiency for wireless power and data transfer in implantable medical devices.

Photonic generation of microwave binary digital modulation signal with format agility and parameter tunability

Abstract A method for photonic generation of arbitrary microwave binary digital modulation signal based on polarization switch is proposed and investigated. A polarization modulator is utilized to switch the direction of a linearly-polarized optical signal between two orthogonal axes. Then, a polarization-dependent modulation structure is employed to modulate an external RF signal to the two optical carriers with different polarization directions respectively. The modulation structure consists of a polarization beam splitter, two parallel placed dual-drive Mach–Zehnder modulators and an optical combiner. By adjusting the parameters of the two modulators, different optical sidebands can be obtained in two polarization directions. After optical-to-electrical conversion, a microwave amplitude shift keying (ASK), frequency shift keying (FSK) or phase shift keying (PSK) signal can be achieved. The modulation format, bit-rate and carrier frequency of the generated signal can be tuned independently and flexibly. A simulation is demonstrated to verify the proposed scheme, a 2-Gbit/s 40-GHz ASK signal, a 2-Gbit/s FSK signal with carrier frequencies of 20 and 40 GHz, and a 2-Gbit/s 20-GHz PSK signal are obtained. The scheme has good tunability.

An Ultra-Low-Power RFID/NFC Frontend IC Using 0.18 μm CMOS Technology for Passive Tag Applications.

Battery-less passive sensor tags based on RFID or NFC technology have achieved much popularity in recent times. Passive tags are widely used for various applications like inventory control or in biotelemetry. In this paper, we present a new RFID/NFC frontend IC (integrated circuit) for 13.56 MHz passive tag applications. The design of the frontend IC is compatible with the standard ISO 15693/NFC 5. The paper discusses the analog design part in details with a brief overview of the digital interface and some of the critical measured parameters. A novel approach is adopted for the demodulator design, to demodulate the 10% ASK (amplitude shift keying) signal. The demodulator circuit consists of a comparator designed with a preset offset voltage. The comparator circuit design is discussed in detail. The power consumption of the bandgap reference circuit is used as the load for the envelope detection of the ASK modulated signal. The sub-threshold operation and low-supply-voltage are used extensively in the analog design—to keep the power consumption low. The IC was fabricated using 0.18 m CMOS technology in a die area of 1.5 mm × 1.5 mm and an effective area of 0.7 . The minimum supply voltage desired is 1.2 V, for which the total power consumption is 107 W. The analog part of the design consumes only 36 W, which is low in comparison to other contemporary passive tags ICs. Eventually, a passive tag is developed using the frontend IC, a microcontroller, a temperature and a pressure sensor. A smart NFC device is used to readout the sensor data from the tag employing an Android-based application software. The measurement results demonstrate the full passive operational capability. The IC is suitable for low-power and low-cost industrial or biomedical battery-less sensor applications. A figure-of-merit (FOM) is proposed in this paper which is taken as a reference for comparison with other related state-of-the-art researches.

Four-amplitude shift keying-single sideband millimeter-wave signal generation with frequency sextupling based on optical phase modulation

We have proposed and demonstrated a scheme to generate a frequency-sextupling amplitude shift keying (ASK)-single sideband optical millimeter (mm)-wave signal with high dispersion tolerance based on an optical phase modulator (PM) by ably using the−4th-order and +2nd-order sidebands of the optical modulation. The ASK radio frequency signal, superposed by a local oscillator with the same frequency, modulates the lightwave via an optical PM with proper voltage amplitudes, the +2nd-order sideband carries the ASK signal with a constant slope while the −4th-order sideband maintains constant amplitude. These two sidebands can be abstracted by a wavelength selective switch to form a dual-tone optical mm-wave with only one tone carrying the ASK signal. As only one tone bears the ASK signal while the other tone is unmodulated, the generated dual-tone optical mm-wave signal has high dispersion tolerance.

Differentiating ASK Demodulator for Contactless Smart Cards Supporting VHBR

This brief proposes an amplitude shift keying (ASK) demodulator that uses switched-capacitor differentiators to make it compliant with the very high bit rate amendment to the ISO/IEC 14443 standard for contactless smart card applications. These differentiators detect transitions in modulated ASK signals with a carrier frequency of 13.56 MHz at data rates up to 6.78 Mb/s. The demodulator has been implemented in 0.18 μm CMOS technology. The total power consumption is under 350 μW. Measured results confirm correct operation, and it is further shown that this differentiating scheme allows the modulation index to be reduced to 2.56%.

An All-Optical Modulation Format Conversion for 8QAM Based on FWM in HNLF

In this letter, we propose and experimentally demonstrate an all-optical modulation format conversion scheme from amplitude shift keying (ASK) and quadrature phase shift keying (QPSK) to 8-ary quadrature amplitude modulation (8QAM), using four-wave mixing (FWM) effect in highly nonlinear fiber. In the FWM process, a 20-Gbits/s return-to-zero QPSK (RZ-QPSK) signal and a 10-Gbit/s ASK signal are utilized as probe light and pump light, respectively. A 30-Gbits/s RZ-8QAM signal, which is the idler light, is successfully obtained with optical signal-to-noise ratio larger than 30 dB and bit-error rate lower than <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$10^{-5}$</tex></formula> .

Novel high-speed carrier-suppressed return-to-zero frequency shift keying signal generation and transmission

A novel carrier-suppressed return-to-zero frequency shift keying (CSRZFSK) transmitter that can operate at 40 Gb/s and above is proposed for the first time. The transmission characteristics of the CSRZFSK signal at 40 Gb/s compared with differential quadrature phase shift keying (DQPSK) signal and amplitude shift keying (ASK) signal are investigated under different dispersion management. Simulation results show that CSRZFSK has the best nonlinear tolerance and longest transmission distance when compared with DQPSK and ASK signals. A 40 Gb/s CSRZFSK signal gives only a 0.1 dB sensitivity penalty while DQPSK and ASK give 0.6 and 0.7 dB, respectively.

Simultaneous Transmission of ASK, OCS-ASK and FSK Signals in A Radio over Fiber System Using A Single-drive Mach-Zehnder Modulator

We propose a bidirectional radio over fiber (RoF) system for simultaneous generation and transmission of amplitude shift keying (ASK), optical carrier suppressed amplitude shift keying (OCS-ASK) and frequency shift keying (FSK) signals based on one single-drive Mach-Zehnder modulator (MZM). The feasibility of the proposal is verified by experiments and error-free performances are achieved for all the data.

IRZ–Manchester coding for downstream signal modulation in an ONU-source-free WDM-PON

Inverted return-to-zero (IRZ)–Manchester coding is proposed for optical downstream signal using amplitude shift keying (ASK) modulation in an optical network unit (ONU)-source-free wavelength-division-multiplexing passive optical network (WDM-PON), and ASK modulation is used for the optical upstream signal generation using remodulation over the optical downstream signal. With IRZ–Manchester coding, differential phase shift keying (DPSK) modulation can be overlaid on the downstream optical ASK signal for broadcasting services. Our experimental results show that the IRZ–Manchester coded optical ASK downstream signal has no modulation extinction ratio restrictions from the overlaid DPSK modulation, and that the remodulated optical upstream signal has very limited signal crosstalk from the downstream signals. In comparison with the conventional schemes using only Manchester coding or IRZ modulation, the proposed IRZ–Manchester coded modulation scheme shows better performance under different PON upstream and downstream traffic bit rate ratios.

A low power automatic gain control loop for a receiver

This paper proposes a new structure to lower the power consumption of a variable gain amplifier (VGA) and keep the linearity of the VGA unchanged. The structure is used in a high rate amplitude-shift keying (ASK) based IF-stage. It includes an automatic gain control (AGC) loop and ASK demodulator. The AGC mainly consists of six-stage VGAs. The IF-stage is realized in 0.18 μm CMOS technology. The measurement results show that the power consumption of the whole system is very low. The system consumes 730 μA while operating at 1.8 V. The minimum ASK signal the system could detect is 0.7 mV (peak to peak amplitude).

A 13.56 MHz Radio Frequency Identification Transponder Analog Front End Using a Dynamically Enabled Digital Phase Locked Loop

Received October 5 2009, Revised December 28 2009, Accepted January 22 2010 The analog front end (AFE) of a radio frequency identification transponder using the ISO 14443 type A standard with a 100% amplitude shift keying (ASK) modulation is proposed in this paper and verified by circuit simulations and meas‐urements. This AFE circuit, using a 13.56 MHz carrier frequency, consists of a rectifier, a modulator, a demodulator, a regulator, a power on reset, and a dynamically enabled digital phase locked loop (DPLL). The DPLL, with a charge pump enable circuit, was used to recover the clock of a 100% modulated ASK signal during the period. A high voltage lateral double diffused metal‐oxide semiconductor transistor was used to protect the rectifier and the clock recovery circuit from high voltages. The proposed AFE was fabricated using the 0.18 µm standard CMOS process, with an AFE core size of 350 µm × 230 µm. The measurement results show that the DPLL, using a demodulator output sig‐nal, generates a constant 1.695 MHz clock during the period of the 100% ASK signal. Keywords: Radio frequency identification, Analog front end, Amplitude shift keying, Digital phase locked loop 1. INTRODUCTION Recently, radio frequency identification (RFID) technology has become a key component in manufacturing, distribution industries, and banking services [1]‐[3]. Mobile RFID is widely used at the high frequency of 13.56 MHz, and in the ultra‐high frequency band from 860 to 960 MHz. The mobile RFIDs that use the 13.56 MHz carrier frequency are limited to near field communication, however this limitation is very useful in the protection of privacy and in personal authentication proc‐esses. These mobile RFIDs, using the ISO 14443 type A stan‐dard, use 100% amplitude shift keying (ASK) modulation to create a pause period. A normal clock recovery circuit has a difficulty in recovering the clock during the period. It should be noted that the ISO 14443 type A and type B meth‐ods have different modulation index values, 100% and 10%, respectively [1]. We propose a new circuit structure for an RFID trans‐ponder analog front end (AFE) which easily recovers the clock of a 100% modulated ASK signal using the ISO 14443 type A standard. A digital phase locked loop (DPLL) incorpo‐rating a charge pump enable circuit is used to recover the clock of a 100% modulated ASK signal during the pe‐riod. We also used a high voltage lateral double diffused metal‐oxide semiconductor transistor (LDMOST) [4] for the rectifier and clock recovery circuit of the DPLL at the point where the high input signal is directly applied. The proposed RFID transponder AFE was verified by circuit simulations and the measurements of a fabricated chip manufactured using the 0.18 µm complementary MOS (CMOS) standard process.

Generation of amplitude-shift-keying optical signals using silicon microring resonators

We demonstrate the generation of amplitude-shift-keying (ASK) optical signals using a system of parallel microring resonators. By independently modulating two symmetric microring resonators arranged in a Mach-Zehnder configuration, we realize the generation of three levels. The proposed scheme can be extended to any number of logic levels, which effectively increases the data rate of an optical link using slower modulators. Here, we separately utilize thermo-optic and ultrafast all-optical modulation schemes to generate ASK signals on a silicon photonic chip.

All-optical M-ary ASK signal demultiplexer based on a photonic analog-to-digital conversion

An all-optical M-ary amplitude shift keying (ASK) signal demultiplexer is proposed and demonstrated. It allowed us to seamlessly demultiplex a high bit-rate optical M-ary ASK signal into on-off keying (OOK) signals without O/E conversion. It is composed of multilevel thresholding using self-frequency shift and OOK signal generation using optical interconnection. A level identification signal is provided as a result of multilevel thresholding and it is fed to an optical interconnection circuit which can generate corresponding OOK signals. We demonstrate the quadrature ASK signal demultiplexing at 100 Gsymbol/s and its error free operation at 10 Gb/s.

Joint Maximum Likelihood Sequence Estimation for Chromatic-Dispersion Compensation in ASK-DPSK Modulation Format

We determine the fundamental impairment mechanism in the chromatic-dispersion (CD)-limited hybrid amplitude shift keying (ASK)-differential phase-shift keying (DPSK) modulation format and propose the employment of joint maximum likelihood sequence estimation (J-MLSE) for CD compensation to extend the transmission reach of such format. We find that it is not the intrasubchannel interference of the ASK or DPSK subchannel but the interaction between these two subchannels that limits the transmission distance. Therefore, electronic equalization of the two subchannels separately cannot improve the overall CD tolerance of the ASK-DPSK signal. J-MLSE, however, exploits the correlation information between the detected ASK and DPSK signals and is numerically shown to improve the CD tolerance of the ASK-DPSK signal significantly

Multilevel signaling for increasing the reach of 10 Gb/s lightwave systems

Polybinary, optical amplitude modulated phase shift keying (AM-PSK) polybinary, M-ary amplitude shift keying (ASK), and polyquaternary signaling schemes operating at 10 Gb/s are investigated in 1550-nm lightwave systems operating over standard, single-mode fiber. The premise for exploring these signal types is that they concentrate power at frequencies closer to the optical carrier where phase distortion of the optical field from chromatic dispersion is less severe. Issues such as modulator chirp, optimal level spacing in a 4-ary ASK signal, and phase modulated to amplitude modulated (PM-AM) noise conversion from a nonzero laser linewidth are studied. It is found that higher order polybinary signals do not offer an improvement in dispersion tolerance over a duobinary signal. 4-ary ASK is demonstrated to increase the dispersion-limited distance to 225 km experimentally and 350 km through simulation, but at the expense of a /spl sim/8 dB degradation in receiver sensitivity due to the increased number of levels and the signal dependence of signal-spontaneous beat noise. Furthermore, the linewidth requirement for a 4-ary ASK signal is less than 1 MHz in order to minimize the impact of PM-AM relative intensity noise (RIN) when transmitting over 200-300 km.