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The class of the second-order oscillatory almost-cyclostationary processes is characterized. These processes have autocorrelation function which is the superposition of amplitude- and angle-modulated complex sinewaves, where the modulating functions, referred to as evolutionary cyclic autocorrelation functions, depend on both time and lag parameter. This class of processes includes that of the almost-cyclostationary...
All-digital frequency synthesis using two low-pass single-bit Multi-Step Look-Ahead sigma-delta modultors (MSLA SDMs) is presented. MSLA SDMs provide better noise shaping characteristics, i.e. SNDR and bandwidth, than conventional SDMs at the cost of higher hardware complexity. The balance between complexity and performance is adjusted by the number of look-ahead steps, which is an additional design...
To address issues such as increasing number of broadcasting satellite transponders, signal systems becoming increasingly complex and higher requirements on spectrum monitoring in respect of real-time and all-weather coverage are required, this paper introduces a spectrum monitoring equipment based on a high-performance ARM microprocessor platform, as well as the design and implementation of a new...
Tactical Targeting Networks Technology (TTNT) is the latest generation of data link technology. This paper first introduces the basic technical situation and performance of the technology. Secondly, according to the technical characteristics of the new technology, the basic structure of the waveform is analyzed, and the waveform structure of the parallel transmission is given. Finally, according to...
The paper analyses the outcomes of numerical studies into the effect of phase dispersion on broadband elements of a FMCW signal with varying central spectrum frequencies corresponding to the central frequencies of radio channels. We used the International Reference Ionosphere (IRI) model as the background ionosphere, which takes into account the spatiotemporal variability of the radio channel. The...
A model is developed for frequency-dependent response of compact high-speed thin-film lithium-niobate-on-silicon electrooptic modulators. The model predicts potential for > 100 GHz modulation bandwidth.
Optical frequency combs (OFCs) have led to an impressive number of achievements, including multi-heterodyne spectroscopy [1]. Mode-locked OFCs have been widely used due to their exceptional spectral bandwidth, but they usually require sophisticated locking methods to control the free spectral range (FSR) and the absolute frequency of the comb. A promising alternative is provided by electro-optic OFCs,...
One of the most essential building blocks in modem electronics is the flip-flop. A flip-flop operates bi-stably between two states, remaining at a given output level (high or low level) until a specific input control signal changes. For many years, photonics has attempted to build all-optical flip-flops [1-3]; however, the success of these approaches has usually been limited by the dependence of the...
This paper presents the integrated lock-in amplifier dedicated to low noise applications. The proposed circuit provides efficient processing of small, low-frequency signals in conjunction with effective noise minimization. First, the fundamentals of the Phase Sensitive Detection are briefly recalled. Then, the integrated lock-in amplifier is fully presented and described. Deployed IC architecture...
A multirate, fractional-N RF digital phase-locked loop (DPLL) phase modulator implementation for polar transmitter supporting cellular communication standards up to 4G LTE-A is demonstrated for the first time. The RF-DPLL integrates LC-tank-based digital-controlled oscillator (DCO) cores with ΔΣ-noise shaping and fractional sample rate conversion to account for a broad range of frequency bands and...
Planetary bearings inside a helicopter main gearbox (MGB) are key components, successful diagnosis of planetary bearing defects benefits helicopter maintenance, reducing accidents rate and increasing aircraft flightworthiness. Most widely adopted methods for bearing fault diagnosis are envelope analysis and kurtogram; both have achieved many successes in practical application. However, diagnosis of...
The controller design of servo drives for bandwidth improvement will presented in this paper. The delay issues caused by calculation, fdter and PWM generation, etc. are addressed. The controllers of current loop, speed loop and position loop are designed considering the delay and phase margin. Experimental results show the bandwidth for current, speed and position loops of servo drives are significantly...
The paper presents an integrated operational-transconductance-amplifier (OTA) design for medical ultrasound transmitters, particularly used for continuous wave Doppler signal transmission. A dual complementary differential input pair in conjunction with a class AB output stage were designed to drive a large capacitive load. The device operates from a 5-V supply, capable of rail-to-rail operation at...
The first CMOS nonreciprocal transmission line (TL) for wideband tunable full-duplex transceiver front ends, having over 45 dB isolation in a bandwidth of 1.5 GHz and tuning range of 85–110 GHz, is demonstrated. Offering tunable nonreciprocal propagation, this structure is based on a parametric time-varying TL modulated by a 10 GHz signal through distributed capacitive mixing. Two capacitive mixers...
This paper proposes a frequency-domain OOK (F-OOK) modulation transmitter with a phase rotator and a 4-stage ring digital/voltage-controlled oscillator (D/VCO) to achieve high energy, bandwidth and area efficiencies. Both frequency deviation and frequency modulation are realized in the phase domain by utilizing the phase rotator. A 9-bit phase rotator covering a phase shifting range of 180° is designed...
A constant-envelope modulator is presented for Internet-of-Things (IoT) wireless connectivity technologies such as Bluetooth Low-Energy (BLE) and IEEE 802.15.4 ZigBee. It is based on the recently introduced hybrid digital phase-locked loop (HDPLL). It features direct frequency modulation of a digitally controlled oscillator (DCO) and a 2nd-order Delta-Sigma (ΔΣ) mixed-signal closed-loop phase/frequency...
The need for low-noise, highly-linear, programmable chirp generators makes digital phase-locked loops (DPLLs) an attractive solution for radar sensors. This paper presents a general analysis and comparison of the two main techniques enabling wideband frequency modulation (FM) in PLLs, namely the two-point injection and the pre-emphasis. It is shown that while the two topologies are equivalent in term...
This work presents two completely printable chipless RFID tags for low-cost item labeling. The first developed tag is based on circular ring resonators where each resonator codifies a tag coding notch position. Therefore, the tag structure is scalable, printable and compact size. Moreover, a novel encoding methodology is employed to preserve the notch width and position while coding. The second developed...
We propose a simple but effective approach for the estimation of power spectra at very low frequencies (down to the tens of mHz range) by exploiting the characteristics of the sound system (sound card) and the computational power of modern personal computers. A simple mixer board has been designed that allows to transfer the low frequency region of the spectrum at a higher frequency in the passband...
In this paper a simple method of design and implementation of a LFM (linear frequency modulation) waveform or chirp of 3μsec pulse duration with 200MHz bandwidth, using DDS (direct digital synthesis) and FPGA [Virtex4 LX25FF668 (−10)] is explained. The design and implementation of LFM consists of, 1) Design and realization of spot frequency generation using DDS [AD9858]. 2) Design and realization...
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