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A modified double rhombus antenna is designed to detect cell phones for post disaster search and rescue operations. The antenna consists of two rhombus shape dipoles with different size fed by microstrip line with a truncated ground plane which acts as reflector to produce end fire radiation. It was found that the directivity of the antenna depends mainly on the length and width of the dielectric...
Automatic Gain Control (AGC) is an integral part of any radio receiver. It is needed to maintain the signal level within an acceptable range that would yield the best possible SNR at the receiver output. In this paper, an AGC topology that was used for a CMOS, OFDM-based, digital radio receiver is introduced. The basic AGC algorithm is summarized. The AGC works on two stages, the RF stage and the...
This paper studies the downlink closed loop transmission in the 3G long term evolution (LTE) system. We propose a precoding matrix selection algorithm from a finite codebook. The precoding, antenna selection, adaptive modulation and coding (AMC) require the channel information fed back from receiver to optimize the system performance. We study the codebook design and precoding matrix selection in...
Millimeter-wave imaging system is developing very quickly in airport security and aircraft navigation. Radiometer plays a key role in the millimeter-wave imaging system. The characteristic of full power radiometer and Dicke radiometer is compared. The key parts for a new direct-detection radiometer is designed and analyzed. The chips for LNA, detector and integrator are chosen and simulated, which...
We propose a robust maximum a posteriori probability (MAP) blind bit-rate detector (BBRD) for a fixed frame-length multiple access system which employs variable-gain receiver power and repetition encoding. this detector considers the rate detection (RD) as a multihypothesis test and maximizes the likelihood functions (LF)s to find the true bit-rate. Assuming that we have no knowledge about the receiver...
Cooperative relaying has been studied extensively in the literature to exploit spatial diversity gains by having each source transmit its messages through multiple independently fading relay paths. In multiuser systems where multiple sources may access the same set of relays simultaneously, CDMA spreading techniques along with multiuser detection schemes have been proposed in the literature to eliminate...
A blind multiuser receiver is proposed for multiuser detection of UWB systems in a realistic indoor channel. The proposed blind multiuser receiver is based on the constant-modulus algorithm (CMA), which is known to provide satisfactory performances in a blind setting. In order to overcome the CMA interference capture problem typical of a multiuser scenario, we propose to adopt a two stage receiver:...
Wideband waveform-level precoding with simple energy detector receiver is investigated in this paper. The motivation is to provide a cheap radio network with simple receivers and sophisticated transmitters. The energy detector receiver performs relatively poorly, but waveform-level precoding can be used to compensate for the performance loss. Waveform-level precoding is a transmitter-side processing...
Some utility-connected power electronics applications such as reversible rectifiers and active power filters need accurate measurements of the utility phase angle. A phase locked loop (PLL) is an important component of such systems. This paper describes the development of a three phase PLL for utility angle measurement using a new bit-stream control technique, which has several advantages when used...
As intrinsic device gain and power supply voltages decrease with CMOS technology scaling, it is becoming increasingly challenging for designers of conventional opamp-based switched-capacitor circuits to meet gain and output swing targets, and to ensure stability. Zero-crossing based circuits (ZCBC) are presented as an alternative architecture where each opamp is replaced with a current source and...
This paper focuses on the detection performances achievable in the presence of Low Probability of Intercept (LPI) radar signals. It well known that the radar community is widely investigating LPI waveforms to reduce the Range Advance Factor (RAF) obtainable with Electronic Support Measure (ESM) systems. Several filtering strategies for LPI signals processing are already available in open literature,...
The not expensive radiometric module have been created in 3-mm wave band for an array receiver of the passive imaging system. The module contains a single amplifying microcircuit and low-barrier Shottky diode as a detector. The module operated in frequency band (86...95) GHz and had temperature sensitivity 15 mK/Hz1/2 in the total power mode.
Combined effect of polarization mixing and differential group delay (DGD) on sinusoidal and random jitter tolerance is investigated. Requirements for tolerable DGD, loop bandwidth and loop delay are extrapolated.
A single-in-differential-out variable gain wideband LNA without on-chip inductor for CMMB TV tuner is implemented in 0.18 ??m CMOS. The LNA provide gain modes ranging from 18 dB to -12 dB with a 6 dB step. The LNA exhibits an IIP3 of 7.76 dBm and an NF of less than 2.4 dB at 18 dB gain mode. The output imbalance is only 0.01 dB in amplitude and 0.2 degree in phase at 18 dB gain mode. The IIP3 at -12...
Noise performance of an InGaSb avalanche photodiode (APD) with 10% indium fraction has been studied at two temperature levels to explore the feasibility of using this device in an advanced photo-receiver system for mid-infrared wavelengths. Simulation results show that, optimum gain increases from 2.5 at room temperature to 3.2 at 90??C. Although this device exhibits slightly better noise performance...
Error rate performance of the layered spacetime code (LST) combined with Alamouti coding (AC) in flat Rayleigh fading channel is investigated. With the sorted-QR-decomposition-based decision feedback detector (SQRD-DFD), the channel matrix is Q-R decomposed with proper column permutation to minimize the possibility of error propagation. Error rate performance of the LST combined with AC is compared...
We report the development of ultrasensitive photoreceivers, based on ultra high gain and low excess noise APDs, with sensitivities of -35.5 dBm at 2.488 Gbps and 10-10 BER and the potential for 6-12 dB sensitivity enhancement at higher bit rates. Current APD devices are not capable of simultaneous high gain and low noise. The developed APD detectors enable the achievement of optimum sensitivity at...
Detecting a known signal in additive noise is a widespread problem. Two different cases have been processed in the literature whether the noise power is known or not. Here we consider the case where the noise power could vary between the null and alternative hypothesis. This situation occurs if the receiver electronic behave differently if the signal of interest (SOI) is present or when the signal...
In this preliminary article we consider the problem of estimating an unknown noise-gain for a Markov chain observed through a scaled Brownian motion. It is assumed that the unknown noise-gain is time invariant. Two objectives are addressed in this work, 1) compute an estimation scheme that is fast, and 2) compute an estimation scheme without recourse to stochastic integration. To address the first...
This paper describes a fast received signal strength indicator (RSSI) circuit for wireless communication application. It is developed using a novel power detector with a fast settling time. The power detector is consisted of a variable gain amplifier (VGA), a peak detector, and a comparator in a closed loop. The VGA achieved a wide gain range in a closed loop form. For the peak detector, a fast settling...
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