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The altitude information is very important for the safety of aircraft. Among many types of modulation, the Frequency Modulated Continuous Wave (FMCW) was the most common used in radar altimeter. Although classical Fast Fourier Transform (FFT) method has been successfully used in short range measurement for Radar Altimeter [1], the problem of altitude estimation in long distance for Radar Altimeter...
In this paper, constellations-constrained capacities of a parametric underwater communication system, which employs robust modulation for quadrature-amplitude-modulation, are analysed.
A digital Class-D audio amplifier is presented in this paper. This amplifier uses a sixth-order PWM modulator to generate the driver signal of the output stage of the amplifier. The transformation of pulse-amplitude-modulation (PAM) signal to pulse-width-modulation (PWM) signal is moved into the closed sigma-delta modulator loop that the noise and distortion generated during the transformation of...
We report on terahertz wireless communication experiments at 0.2 THz, using a commercial GaAs field-effect-transistor as detector. For the first time, we will present the transmission of pseudo-random bit sequence at 0.2 THz using this commercial transistor and demonstrate open eye-patterns up to 1.5 Gbps. This transistor is integrated into a machined horn, so that its sensitivity is improved to 1...
In this paper we present a new architecture for PLL-based high-speed demodulation of frequency-modulated AFM signals. In our approach, we use single-sideband frequency up-conversion to translate the AFM signal from the position sensitive detector to a fixed intermediate frequency of 10MHz. In this way, we fully benefit from the excellent noise performance of PLL-based FM demodulators still avoiding...
We consider distributed detection applications for a fusion center that has a limited time to collect, weight and fuse local decisions to produce a global decision in a wireless sensor network that uses a random access protocol. When this time is not long enough to collect decisions from all nodes in the network, a strategy is needed for collecting those with the highest reliability. This is accomplished...
Integrating time constants of the order of a few seconds is one of the main bottlenecks in the design of biomedical chips. To achieve a low cut-off frequency with 60 dB linearity, mixed-signal feedback utilizing the properties of a ΣΔ ADC is proposed. To verify the performance, a 10-bit ΣΔ modulator with the proposed technique is designed to be implemented in 0.18 μm CMOS AMS technology. The design...
In this paper, a new method of calculating the transfer functions of continuous-time (CT) sigma-delta modulators is presented. The common approach of calculating the transfer functions is to analyze a discrete-time (DT) equivalent of the CT loop filter together with the CT input filter path. The DT equivalent is most commonly obtained via either the impulseinvariant or the modified Z-transformation...
This paper describes a method to improve the linearity, area or SNR of feedback (FB) compensated Sigma-Delta (ΣΔ) modulators. These performance limiting factors are often related to the outer loop feedback DAC or to the 1st integrator of the ΣΔ-modulator in a FB-compensated modulator. This work focuses on improvements of the 1st integrator. The origin of these problems is the output swing of the 1...
In the last years, the introduction of distributed energy resources increases the complexity of distribution grid management system, which requires performing communication infrastructures. Moreover, an optimal power management requires a direct data exchange with home and industrial automation and energy systems. A well known technology, the Power Line Communication (PLC), seems to be able to satisfy...
This paper considers the implementation of a continuous-time low-pass single-bit ΔΣ analog-digital converter (ADC) for radar applications. By taking advantage of the high transit frequency of a 0.25μm SiGe BiCMOS technology, the 3rd-order modulator operates at 1.92GHz and achieves 77.8dB SNDR within a bandwidth of 15MHz, when simulating the sensitive circuit parts on transistor level. Thanks to the...
In this paper, a CMOS monolithic light to sigma-delta modulator for environmental monitoring applications is newly proposed. The proposed chip is attractive due to the fact that analog processing circuits and light sensor are integrated robustly and compactly. The output signal of the proposed chip is a pulse stream, it could be easily sent over a wide range of transmission media, such as PSN, radio,...
Based on the previously developed monostatic HF radar cross section model for swell contaminated seas, a new inversion algorithm for swell information from radar sea echoes is proposed. The received electric field time series with external white Gaussian noise is first simulated, from which the Doppler spectrum is obtained as a periodogram. Next, all swell peaks in the spectrum are identified and...
In this letter, a clock-aided and data-aided frequency recovery method for shaped offset quadrature phase shift keying (SOQPSK) signals is proposed. Based on the pulse amplitude modulation (PAM) representation of continuous phase modulation (CPM), we eliminate the modulation of the SOQPSK signals and thus the problem turns to be the frequency estimation of a complex sinusoid in complex noise. It is...
The performance of GPS L5 acquisition is greatly affected by secondary codes, the NH codes with possible bit sign transition every millisecond modulated on the signal, which limits the achievable coherent integration gain. In this paper, a new acquisition method of GPS L5 signal, called Inter-Block Differentially Coherent Integration (IBDCI), is proposed to deal with such problem. The proposed method...
This paper introduces a low-noise, low-power amplifier for high-impedance sensors. An innovative circuit using an auto-zeroed architecture combined with frequency modulation to reject offset and low-frequency noise is proposed and analysed. Special care was given to avoid broadband noise aliasing and chopping in the signal path, and to minimize both the resulting equivalent input offset voltage and...
In this work, we study a special kind of primary user emulation (PUE) attack, named wireless microphone user emulation (WMUE) attack in white space cognitive radio networks. In WMUE attacks, a malicious user emulates wireless microphone (WM) signals in order to block secondary users. Existing work on WMUE attack detection deals with single channel senario. Although multi-channel WM (MCWM) systems...
This paper proposes a novel approach of designing functional blocks to implement Proportional, Integral and Derivative action in hybrid bit-stream environment. The developed functional blocks which do not convert the element output to bit-stream signal assure the minimization of the noise inside the controller by avoiding bit-stream converter, save more hardware resources and reduce the design complexity...
This paper presents a two-path design of quadrature band-pass modulators and discusses the architectural level implementation issues for power reduction. The methodology uses an architecture which locks IF frequencies to the sampling frequency. The basic delay based solution is converted into integrator based solution for the implementation. Robustness of the structure against the mismatch...
A dual mass vibratory gyroscope sensor demonstrates the quadrature frequency modulated (QFM) operating mode, where the frequency of the circular orbit of a proof mass is measured to detect angular rate. In comparison to the mode-matched open loop rate mode, the QFM mode receives the same benefit of improved SNR but without the penalties of unreliable scale factor and decreased bandwidth. A matched...
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