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[IEEE SoutheastCon 2018 - St. Petersburg, FL (2018.4.19-2018.4.22)] SoutheastCon 2018 - An Examination of Dichotomous and Centroid Tracking of a Monopulse Angle Tracking Unit
摘要： The engineering community is confident in its assessment of how an angle tracker will perform in a multi-target environment as the target-to-tracker range decreases, causing targets to leave the tracker antenna beam. When one target signal dominates due to the angular separation of the targets, the tracker will center on the dominating signal. It is not well understood how the tracker will behave when angle separation is not the limiting factor in signal strength. That topic is addressed in this paper. Specifically, we show how angle error signal normalization impacts track loop dynamics in a dual target scenario. If the error signal is normalized by an Automatic Gain Control (AGC), the behavior will depend upon the Doppler frequency separation of the two targets relative to the AGC bandwidth. The problem is addressed from a theoretical perspective, and via simulation. The theoretical and simulation results agree well.
关键词： simulation,AGC,angle tracker,Automatic Gain Control,Doppler frequency,monopulse
更新于2025-09-23 15:21:01
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34-GBd Linear Transimpedance Amplifier for 200-Gb/s DP-16-QAM Optical Coherent Receivers
摘要： High spectral ef?ciency offered by the coherent optical communication links makes them attractive for the next-generation optical communication links. Using advanced modulation schemes such as dual-polarization quadrature-amplitude modulation (DP-QAM) data rates beyond 200 Gb/s can be achieved. A key component of such links is the wide-bandwidth and high-linearity coherent optical receiver. In this paper, we present a fully differential (FD) optical receiver architecture consisting of a variable-gain transimpedance ampli?er (VG-TIA) followed by a VG ampli?er (VGA). The proposed optical receiver employs a dual-feedback automatic gain control (AGC) loop that controls both the front-end VG-TIA and the following VGA to achieve both low-noise and high-linearity operation. A new photodiode (PD) dc current cancellation scheme is developed and implemented for the full differential front-end TIA. A prototype dual-TIA chip is fabricated in a 0.13-μm SiGe BiCMOS process. The presented TIA achieves 20-pA/√Hz input-referred noise (IRN) density, 27-GHz, 3-dB bandwidth, and 1.5% total harmonic distortion (THD) at 1-mApp input PD current and 500-mVpp output voltage swing. This enables the 34-GBd operation with the bit error rate (BER) of 10?10 and 5.4 × 10?4 using DP-QPSK and DP-16-QAM formats at optical signal-to-noise ratios (OSNRs) of 25 and 30 dB, respectively, demonstrating the 100- and 200-Gb/s single wavelength optical coherent receiver operation. The dual-TIA chip occupies an area of 1.4 mm × 1.6 mm and consumes 313 mW per channel at 34 GBd from a 3.3-V supply.
关键词： dual-polarization (DP)-QPSK,Automatic gain control (AGC),coherent optical communication link,coherent optical receiver,silicon photonics,Linear transimpedance ampli?er (TIA),SiGe,DP-16-quadrature-amplitude modulation (QAM)
更新于2025-09-04 15:30:14