2,097 research outputs found

    A direct-sequence spread-spectrum super-regenerative receiver

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    Current applications of the super-regenerative receiver use narrowband modulations. In this paper a new architecture that allows incoherent detection of spread-spectrum signals is presented. A pseudorandom code generator has been added to the original circuit. It is clocked by the quench oscillator and takes advantage of the characteristic broad reception bandwidth. CDMA can be achieved via ASK and FSK modulated signals with high simplicity in the RF stage as well as low power consumption.Peer ReviewedPostprint (published version

    Super-regenerative receiver at 433MHz

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    This paper presents a receiver for operation in the 433 MHz ISM band. The selected architecture explores the super regeneration phenomena to achieve a high sensitivity for applying in wireless implantable microsystems. This radio frequency (RF) chip can be supplied with a voltage of only 3 V for demodulating signals with powers in the range [ 100, 40] dB. The codulation (modulation and coding) scheme of the binary data is a variation of the Manchester code combined with OOK (on/off keying) modulation. The AMIS 0.7 µm CMOS process was selected for targeting the requirement to fabricate a low cost receiver, whose prototype was integrated in a die with an area of 55 mm2. Also, this receiver is fully compatibility with commercially transmitters for the same frequency

    Low power rf transceivers

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    This thesis details the analysis and design of ultra-low power radio transceivers operating at microwave frequencies. Hybrid prototypes and Monolithic Microwave Integrated Circuits (MMICs) which achieve power consumptions of less than 1 mW and theoretical operating ranges of over 10 m are described. The motivation behind the design of circuits exhibiting ultra low power consumption and, in the case of the MMICs, small size is the emerging technology of Wireless Sensor Networks (WSN). WSNs consist of spatially distributed ‘nodes’ or ‘specks’ each with their own renewable energy source, one or more sensors, limited memory, processing capability and radio or optical link. The idea is that specks within a ‘speckzone’ cooperate and share computational resources to perform complex tasks such as monitoring fire hazards, radiation levels or for motion tracking. The radio section must be ultra low power e.g. sub 1 mW in order not to drain the limited battery capacity. The radio must also be small in size e.g. less than 5 x 5 mm so that the overall speck size is small. Also, the radio must still be able to operate over a range of at least a metre so as to allow radio contact between, for example, rooms or relatively distant specks. The unsuitability of conventional homodyne topologies to WSNs is discussed and more efficient methods of modulation (On-Off Keying) and demodulation (non-coherent) are presented. Furthermore, it is shown how Super-Regenerative Receivers (SRR) can be used to achieve relatively large output voltages for small input powers. This is important because baseband Op-Amps connected at the RF receiver output generally cannot amplify small signals at the input without the output being saturated in noise (10mV is the smallest measured input for 741 Op-Amp). Instrumentation amplifiers are used in this work as they can amplify signals below 1mV. The thesis details the analysis and design of basic RF building blocks: amplifiers, oscillators, switches and detectors. It also details how the circuits can be put together to make transceivers as well as describing various strategies to lower power consumption. In addition, novel techniques in both circuit and system design are presented which allow the power consumption of the radio to be reduced by as much as 97% whilst still retaining adequate performance. These techniques are based on duty cycling the transmitter and receiver and are possible because of the discontinuous nature of the On-Off Keying signal. In order to ease the sensitivity requirements of the baseband receive amplifier a design methodology for large output voltage receivers is presented. The designed receiver is measured to give a 5 mV output for an input power of -90 dBm and yet consumes less than 0.7 mW. There is also an appendix on the non linear modelling of the Glasgow University 50nm InP meta-morphic High Electron Mobility Transistor (50nm mHEMT) and one on the non linear modelling of a commercial Step Recovery diode (SRD). Models for the 50 nm mHEMT and the SRD are useful in the analysis, simulation and design of oscillators and pulse generators respectively

    Signal and noise power spectra in superregenerative oscillators

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    © 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This paper presents a method to quantify noise in superregenerative oscillators. A frequency domain technique, originally intended to determine the signal response, can also be used to determine the noise response. This paper focuses on the procedure required to achieve this. Signal and noise spectra are obtained and their shape is compared. Finally, signal-to-noise ratio is computed for different quench signalsPeer ReviewedPostprint (author's final draft

    Superregeneration revisited: from principles to current applications

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    © 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Wireless communications play a central role in our modern connected lives; at the same time, they constitute a very broad and deep area of research. The elements that make wireless communications possible are a transmitter, which sends information through electromagnetic waves; a medium that is able to transport these waves; and, finally, a receiver, which extracts the information from the-usually very small-amount of energy it is able to collect from the medium.Peer ReviewedPostprint (author's final draft

    Design of a synchronous superregenerative receiver at 2.4 GHz

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    En aquest treball es descriu el procés de disseny i avaluació d'un receptor superregeneratiu per a la banda ISM de 2.4 GHz. El receptor utilitza un nou mode de funcionament en el qual el senyal d'extinció opera síncronament amb les dades rebudes, aconseguint així una notable millora en les prestacions globals del receptor.Postprint (author’s final draft

    Integrated Circuit and System Design for Cognitive Radio and Ultra-Low Power Applications

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    The ubiquitous presence of wireless and battery-powered devices is an inseparable and invincible feature of our modern life. Meanwhile, the spectrum aggregation, and limited battery capacity of handheld devices challenge the exploding demand and growth of such radio systems. In this work, we try to present two separate solutions for each case; an ultra-wideband (UWB) receiver for Cognitive Radio (CR) applications to deal with spectrum aggregation, and an ultra-low power (ULP) receiver to enhance battery life of handheld wireless devices. Limited linearity and LO harmonics mixing are two major issues that ultra-wideband receivers, and CR in particular, are dealing with. Direct conversion schemes, based on current-driven passive mixers, have shown to improve the linearity, but unable to resolve LO harmonic mixing problem. They are usually limited to 3rd, and 5th harmonics rejection or require very complex and power hungry circuitry for higher number of harmonics. This work presents a heterodyne up-down conversion scheme in 180 nm CMOS technology for CR applications (54-862 MHz band) that mitigates the harmonic mixing issue for all the harmonics, while by employing an active feedback loop, a comparable to the state-of-the art IIP3 of better than +10 dBm is achieved. Measurements show an average NF of 7.5 dB when the active feedback loop is off (i.e. in the absence of destructive interference), and 15.5 dB when the feedback loop is active and a 0 dBm interferer is applied, respectively. Also, the second part of this work presents an ultra-low power super-regenerative receiver (SRR) suitable for OOK modulation and provides analytical insight into its design procedure. The receiver is fabricated in 40 nm CMOS technology and operates in the ISM band of 902-928 MHz. Binary search algorithm through Successive Approximation Register (SAR) architecture is being exploited to calibrate the internally generated quench signal and the working frequency of the receiver. Employing an on-chip inductor and a single-ended to differential architecture for the input amplifier has made the receiver fully integrable, eliminating the need for external components. A power consumption of 320 µW from a 0.65 V supply results in an excellent energy efficiency of 80 pJ/b at 4 Mb/s data rate. The receiver also employs an ADC that enables soft-decisioning and a convenient sensitivity-data rate trade-off, achieving sensitivity of -86.5, and -101.5 dBm at 1000 and 31.25 kbps data rate, respectivel

    Experimental investigation of RF fading channels and receiver detection

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    This thesis includes experimental investigation of Multiple Input Multiple Output (MIMO) Radio Frequency (RF) fading channels and detection of superregenerative receivers. Details of experiment design and hardware implementation, data acquisition and analysis, and results for both studies are chronicled into two papers. The first paper investigates the validity of the discrete time triply selective fading channel model for fixed mobile-to-mobile MIMO channels. A 2x2 MIMO-OFDM testbed using the Altera Stratix III EP3SL150F field programmable gate array (FPGA) DSP development kit is used for acquiring experimental data. Subsequent offline signal processing and analysis are done in MATLAB. The Channel Impulse Response (CIR) is estimated using the Time domain Least Squares (LS) method. The channel coefficient covariance matrix is decomposed into its Kronecker factors - the spatial correlation matrix, inter-tap correlation matrix, and temporal correlation matrix. This study verifies the theoretical hypothesis and simulation results. The second paper proposes a novel method for detection of the superregnerative RF receivers. The algorithm is based on active stimulation and correlation of long pseudonoise (PN) sequences. An experimental setup is established using the Universal Software Radio Peripheral (USRP) as the primary component. Simulation results show that the maximum length PN sequences exhibit the best correlation properties among different potential stimulation signals. Proposed method improves range and accuracy of detection as compared to the passive detection and power detection methods --Abstract, page iv

    Integrated Circuit and System Design for Cognitive Radio and Ultra-Low Power Applications

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    The ubiquitous presence of wireless and battery-powered devices is an inseparable and invincible feature of our modern life. Meanwhile, the spectrum aggregation, and limited battery capacity of handheld devices challenge the exploding demand and growth of such radio systems. In this work, we try to present two separate solutions for each case; an ultra-wideband (UWB) receiver for Cognitive Radio (CR) applications to deal with spectrum aggregation, and an ultra-low power (ULP) receiver to enhance battery life of handheld wireless devices. Limited linearity and LO harmonics mixing are two major issues that ultra-wideband receivers, and CR in particular, are dealing with. Direct conversion schemes, based on current-driven passive mixers, have shown to improve the linearity, but unable to resolve LO harmonic mixing problem. They are usually limited to 3rd, and 5th harmonics rejection or require very complex and power hungry circuitry for higher number of harmonics. This work presents a heterodyne up-down conversion scheme in 180 nm CMOS technology for CR applications (54-862 MHz band) that mitigates the harmonic mixing issue for all the harmonics, while by employing an active feedback loop, a comparable to the state-of-the art IIP3 of better than +10 dBm is achieved. Measurements show an average NF of 7.5 dB when the active feedback loop is off (i.e. in the absence of destructive interference), and 15.5 dB when the feedback loop is active and a 0 dBm interferer is applied, respectively. Also, the second part of this work presents an ultra-low power super-regenerative receiver (SRR) suitable for OOK modulation and provides analytical insight into its design procedure. The receiver is fabricated in 40 nm CMOS technology and operates in the ISM band of 902-928 MHz. Binary search algorithm through Successive Approximation Register (SAR) architecture is being exploited to calibrate the internally generated quench signal and the working frequency of the receiver. Employing an on-chip inductor and a single-ended to differential architecture for the input amplifier has made the receiver fully integrable, eliminating the need for external components. A power consumption of 320 µW from a 0.65 V supply results in an excellent energy efficiency of 80 pJ/b at 4 Mb/s data rate. The receiver also employs an ADC that enables soft-decisioning and a convenient sensitivity-data rate trade-off, achieving sensitivity of -86.5, and -101.5 dBm at 1000 and 31.25 kbps data rate, respectivel
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