8,488 research outputs found
Adaptive differential amplitude pulse-position modulation technique (DAPPM) using fuzzy logic for optical wireless communication channels
In the past few years, people have become increasingly demanding for high
transmission rate, using high-speed data transfer rate, the number of user increased
every year, therefore the high-speed optical wireless communication link have
become more popular. Optical wireless communication has the potential for
extremely high data rates of up to tens of Gigabits per second (Gb/s). An optical
wireless channel is usually a non-directed link which can be categorized as either
line-of-sight (LOS) or diffuses. Modulation techniques have attracted increasing
attention in optical wireless communication, therefore in this project; a hybrid
modulation technique named Differential Amplitude Pulse-Position Modulation
(DAPPM) is proposed to improve the channel immunity by utilizing optimized
modulation to channel. The average symbol length, unit transmission rate, channel
capacity, peak-to-average power ratio (PAPR), transmission capacity, bandwidth
requirement and power requirement of the DAPPM were determined and compared
with other modulation schemes such as On-Off Key (OOK), Pulse-Amplitude
Modulation (PAM), Pulse-Position Modulation (PPM), Differential Pulse-Position
Modulation (DPPM), and Multilevel Digital Pulse Interval Modulation (MDPIM).
Simulation result shows that DAPPM gives better bandwidth and power efficiency
depending on the number of amplitude level (A) and the maximum length (L) of a
symbol. In addition, the fuzzy logic module is developed to assist the adaptation
process of differential amplitude pulse-position modulation. Mamdani fuzzy logic
method is used in which the decisions made by the system will be approaching to
what would be decided by the user in the real world
Nanowire Volatile RAM as an Alternative to SRAM
Maintaining benefits of CMOS technology scaling is becoming challenging due
to increased manufacturing complexities and unwanted passive power
dissipations. This is particularly challenging in SRAM, where manufacturing
precision and leakage power control are critical issues. To alleviate some of
these challenges a novel non-volatile memory alternative to SRAM was proposed
called nanowire volatile RAM (NWRAM). Due to NWRAMs regular grid based layout
and innovative circuit style, manufacturing complexity is reduced and at the
same time considerable benefits are attained in terms of performance and
leakage power reduction. In this paper, we elaborate more on NWRAM circuit
aspects and manufacturability, and quantify benefits at 16nm technology node
through simulation against state-of-the-art 6T-SRAM and gridded 8T-SRAM
designs. Our results show the 10T-NWRAM to be 2x faster and 35x better in terms
of leakage when compared to high performance gridded 8T-SRAM design
A Compact CMOS Memristor Emulator Circuit and its Applications
Conceptual memristors have recently gathered wider interest due to their
diverse application in non-von Neumann computing, machine learning,
neuromorphic computing, and chaotic circuits. We introduce a compact CMOS
circuit that emulates idealized memristor characteristics and can bridge the
gap between concepts to chip-scale realization by transcending device
challenges. The CMOS memristor circuit embodies a two-terminal variable
resistor whose resistance is controlled by the voltage applied across its
terminals. The memristor 'state' is held in a capacitor that controls the
resistor value. This work presents the design and simulation of the memristor
emulation circuit, and applies it to a memcomputing application of maze solving
using analog parallelism. Furthermore, the memristor emulator circuit can be
designed and fabricated using standard commercial CMOS technologies and opens
doors to interesting applications in neuromorphic and machine learning
circuits.Comment: Submitted to International Symposium of Circuits and Systems (ISCAS)
201
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