We analyze the bit error rate (BER) performance of optical coherent communication systems employi... more We analyze the bit error rate (BER) performance of optical coherent communication systems employing multi-section monolithic tunable lasers with large excess phase noise. The BER of the coherent system utilizing a second-order decision-directed digital phase-locked loop (DD-PLL) for phase tracking was computed numerically. Experimental results have also been demonstrated with a 16-quadratic-amplitude modulation coherent system deploying a sampled-grating distributed Bragg reflector laser at 16 Gbaud that confirms the performance of the second-order DD-PLL in tracking the excess phase noise.
2016 IEEE Sixth International Conference on Communications and Electronics (ICCE), 2016
Self-encoded spread spectrum (SESS) systems derive their spreading codes from the data being tran... more Self-encoded spread spectrum (SESS) systems derive their spreading codes from the data being transmitted. The inherent memory and time diversity in SESS modulation have been exploited for robust performance in jamming and multipath environments, as well as Global Navigation Satellite System (GNSS) applications. While SESS lends itself to random spreading codes, the receiver must acquire an estimate of the current spreading code before communication can proceed. In this paper we propose a method using chipoffset correlation to obtain an initial code estimate that is sufficient for continued system operation. We describe and analyze the chip-offset correlation method that necessitates a minor modification to SESS system.
2018 IEEE Symposium on Electromagnetic Compatibility, Signal Integrity and Power Integrity (EMC, SI & PI), 2018
This paper describes a proof-of-concept hybrid EMP shelter with a subfloor of reinforced conducti... more This paper describes a proof-of-concept hybrid EMP shelter with a subfloor of reinforced conductive concrete together with a modular steel clamp together shielding system. Test results demonstrate that such hybrid shielding structures can provide EMP protection per MIL-STD 188-125-1 requirements.
IEEE Letters on Electromagnetic Compatibility Practice and Applications, 2020
Conductive concrete structures have been previously demonstrated to perform electromagnetic shiel... more Conductive concrete structures have been previously demonstrated to perform electromagnetic shielding that satisfied the shielding effectiveness requirements of military standard 188-125-1. The concrete mixture contains proportions of conductive materials together with taconite aggregate for the absorption of EM energy. This letter describes the conductive concrete filter concept as a lossy transmission line and reports the experimental results achieving broadband insertion loss that exceeds 100 dB.
2016 IEEE Avionics and Vehicle Fiber-Optics and Photonics Conference (AVFOP), 2016
We have proposed a scalable, square QAM transmitter using QPSK and phase modulators. The scheme e... more We have proposed a scalable, square QAM transmitter using QPSK and phase modulators. The scheme employs binary electrical signals and generates the desirable Gray coded symbol constellation that minimizes the bit error rate due to symbol errors. The scheme can be tolerant to dispersion-induced ISI due to the straight line symbol transitions from the binary-driven QPSK modulators.
Abstract—In this paper, we propose the self-encoded spread spectrum (SESS) with multirate multime... more Abstract—In this paper, we propose the self-encoded spread spectrum (SESS) with multirate multimedia communication in multipath channel. In multirate multimedia SESS system, each application has their own transmission bit rate. The signal is transmitted through multipath channels each with different channel gain and time delay. We view the main path as the signal resource and other paths as interference. At the receiver side, decorrelation scheme is employed for the main path combined signal not only to reduce the crosstalk between different applica-tions, but also to provide a better estimation for the despreading sequence in the main path. Interference cancellation(IC) in the main path is adopted to improve the correlation detection and iterative detection(ID) performance. Finally the ID is employed to improve the bit error rate (BER). Index Terms—Multirate, multimedia, decorrelation, interfer-ence, iterative detection and self-encoded spread spectrum. I.
2016 IEEE 59th International Midwest Symposium on Circuits and Systems (MWSCAS), 2016
A high performance BJT current source in a folded cascode configuration is shown to achieve high ... more A high performance BJT current source in a folded cascode configuration is shown to achieve high output resistance, wide voltage swing and wide-band frequency response. The design employs dual pnp-npn current mirrors for current feedback between the base and the emitter in order to maintain the constant collector current. Simulation results show that the performance of the proposed folded cascode current source is superior to the conventional current sources, achieving for example an output resistance of 71ΜΩ and an impedance bandwidth product of 2.87Ώ-Ηz at 1mA output current and 1.6V input voltage. The proposed scheme can be implemented with MOSFETs and also provide for an efficient design in current feedback amplifiers.
IEEE Letters on Electromagnetic Compatibility Practice and Applications, 2019
This letter reports the experimental research and development of conductive concrete for building... more This letter reports the experimental research and development of conductive concrete for building shielded structures. The concrete mixture contains proportions of conductive materials, such as carbon and metal fibers together with taconite aggregate consisting of magnetite concentration for the absorption of electromagnetic energy. By embedding wire mesh in the conductive concrete structures, broadband shielding effectiveness from 10 kHz to 1 GHz was achieved that exceeds the requirements per MIL-STD-188-125-1. A proof of concept concrete-metal shelter was implemented with the composite metal wall and roof panels attached to a conductive concrete subfloor to form a hybrid shielding structure. Test results demonstrate that hybrid conductive concrete structures can provide an alternative shielding solution that would meet the MIL-STD-188-125-1 requirements.
We analyze the bit error rate (BER) performance of optical coherent communication systems employi... more We analyze the bit error rate (BER) performance of optical coherent communication systems employing multi-section monolithic tunable lasers with large excess phase noise. The BER of the coherent system utilizing a second-order decision-directed digital phase-locked loop (DD-PLL) for phase tracking was computed numerically. Experimental results have also been demonstrated with a 16-quadratic-amplitude modulation coherent system deploying a sampled-grating distributed Bragg reflector laser at 16 Gbaud that confirms the performance of the second-order DD-PLL in tracking the excess phase noise.
2016 IEEE Sixth International Conference on Communications and Electronics (ICCE), 2016
Self-encoded spread spectrum (SESS) systems derive their spreading codes from the data being tran... more Self-encoded spread spectrum (SESS) systems derive their spreading codes from the data being transmitted. The inherent memory and time diversity in SESS modulation have been exploited for robust performance in jamming and multipath environments, as well as Global Navigation Satellite System (GNSS) applications. While SESS lends itself to random spreading codes, the receiver must acquire an estimate of the current spreading code before communication can proceed. In this paper we propose a method using chipoffset correlation to obtain an initial code estimate that is sufficient for continued system operation. We describe and analyze the chip-offset correlation method that necessitates a minor modification to SESS system.
2018 IEEE Symposium on Electromagnetic Compatibility, Signal Integrity and Power Integrity (EMC, SI & PI), 2018
This paper describes a proof-of-concept hybrid EMP shelter with a subfloor of reinforced conducti... more This paper describes a proof-of-concept hybrid EMP shelter with a subfloor of reinforced conductive concrete together with a modular steel clamp together shielding system. Test results demonstrate that such hybrid shielding structures can provide EMP protection per MIL-STD 188-125-1 requirements.
IEEE Letters on Electromagnetic Compatibility Practice and Applications, 2020
Conductive concrete structures have been previously demonstrated to perform electromagnetic shiel... more Conductive concrete structures have been previously demonstrated to perform electromagnetic shielding that satisfied the shielding effectiveness requirements of military standard 188-125-1. The concrete mixture contains proportions of conductive materials together with taconite aggregate for the absorption of EM energy. This letter describes the conductive concrete filter concept as a lossy transmission line and reports the experimental results achieving broadband insertion loss that exceeds 100 dB.
2016 IEEE Avionics and Vehicle Fiber-Optics and Photonics Conference (AVFOP), 2016
We have proposed a scalable, square QAM transmitter using QPSK and phase modulators. The scheme e... more We have proposed a scalable, square QAM transmitter using QPSK and phase modulators. The scheme employs binary electrical signals and generates the desirable Gray coded symbol constellation that minimizes the bit error rate due to symbol errors. The scheme can be tolerant to dispersion-induced ISI due to the straight line symbol transitions from the binary-driven QPSK modulators.
Abstract—In this paper, we propose the self-encoded spread spectrum (SESS) with multirate multime... more Abstract—In this paper, we propose the self-encoded spread spectrum (SESS) with multirate multimedia communication in multipath channel. In multirate multimedia SESS system, each application has their own transmission bit rate. The signal is transmitted through multipath channels each with different channel gain and time delay. We view the main path as the signal resource and other paths as interference. At the receiver side, decorrelation scheme is employed for the main path combined signal not only to reduce the crosstalk between different applica-tions, but also to provide a better estimation for the despreading sequence in the main path. Interference cancellation(IC) in the main path is adopted to improve the correlation detection and iterative detection(ID) performance. Finally the ID is employed to improve the bit error rate (BER). Index Terms—Multirate, multimedia, decorrelation, interfer-ence, iterative detection and self-encoded spread spectrum. I.
2016 IEEE 59th International Midwest Symposium on Circuits and Systems (MWSCAS), 2016
A high performance BJT current source in a folded cascode configuration is shown to achieve high ... more A high performance BJT current source in a folded cascode configuration is shown to achieve high output resistance, wide voltage swing and wide-band frequency response. The design employs dual pnp-npn current mirrors for current feedback between the base and the emitter in order to maintain the constant collector current. Simulation results show that the performance of the proposed folded cascode current source is superior to the conventional current sources, achieving for example an output resistance of 71ΜΩ and an impedance bandwidth product of 2.87Ώ-Ηz at 1mA output current and 1.6V input voltage. The proposed scheme can be implemented with MOSFETs and also provide for an efficient design in current feedback amplifiers.
IEEE Letters on Electromagnetic Compatibility Practice and Applications, 2019
This letter reports the experimental research and development of conductive concrete for building... more This letter reports the experimental research and development of conductive concrete for building shielded structures. The concrete mixture contains proportions of conductive materials, such as carbon and metal fibers together with taconite aggregate consisting of magnetite concentration for the absorption of electromagnetic energy. By embedding wire mesh in the conductive concrete structures, broadband shielding effectiveness from 10 kHz to 1 GHz was achieved that exceeds the requirements per MIL-STD-188-125-1. A proof of concept concrete-metal shelter was implemented with the composite metal wall and roof panels attached to a conductive concrete subfloor to form a hybrid shielding structure. Test results demonstrate that hybrid conductive concrete structures can provide an alternative shielding solution that would meet the MIL-STD-188-125-1 requirements.
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