Holographic Crosstalk and Signal-to-Noise Ratio in Orthogonal Data Storage

1992 ◽  
Author(s):  
George A. Rakuljic
Keyword(s):  
Data Storage ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Noise Ratio

Improved Signal-to-Noise Ratio Using Phase Compensation in Shift- and Angle-Multiplexed Holographic Data Storage

2008 ◽  
Vol 47 (7) ◽  
pp. 5989-5992 ◽  
Author(s):  
Norihiko Ishii ◽  
Nobuhiro Kinoshita ◽  
Tetsuhiko Muroi ◽  
Koji Kamijo ◽  
Naoki Shimidzu
Keyword(s):  
Data Storage ◽  
Signal To Noise Ratio ◽  
Holographic Data Storage ◽  
Signal To Noise ◽  
Phase Compensation ◽  
Noise Ratio

scholarly journals Dual-polarized multiplexed meta-holograms utilizing coding metasurface

Nanophotonics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 3605-3613 ◽  
Author(s):  
Chunsheng Guan ◽  
Jian Liu ◽  
Xumin Ding ◽  
Zhuochao Wang ◽  
Kuang Zhang ◽  
...  
Keyword(s):  
Data Storage ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Split Ring ◽  
Practical Applications ◽  
Good Imaging ◽  
Linearly Polarized ◽  
Novel Method ◽  
Noise Ratio ◽  
Total Transmittance

AbstractIn this paper, a novel method is proposed to achieve two distinct information channels by simultaneously manipulating both the transmitted cross- and co-polarized components of a 1-bit coding metasurface under linearly polarized incidence. Compared to previously demonstrated incidence-switchable or position multiplexed holograms, our proposed coding meta-hologram can simultaneously project two independent holographic images without inevitable change of the incidence state and can at the same time also avoid crosstalk between different channels. Moreover, the orientation of the double-layered split ring (SR) apertures is specially designed to be 45° or 135° to achieve identical multiplexed functionality for both x-polarized and y-polarized incidences. The proof-of-concept experimental demonstrations present total transmittance efficiency above 30% for the dual linearly polarized incidences at 15 GHz, and good imaging performances with 53.98%/48.18% imaging efficiency, 1.55%/1.46% RMSE, and 29.9/28.72 peak signal-to-noise ratio for the cross-/co-polarized channels under y-polarized incidence, and 47.27%/45.75% imaging efficiency, 1.55%/1.43% RMSE, and 18.74/25.93 peak signal-to-noise ratio under x-polarized incidence, demonstrating great potential of the proposed multiplexed coding meta-hologram in practical applications such as data storage and information processing.

Improving signal-to-noise ratio by use of a cross-shaped aperture in the holographic data storage system

2009 ◽  
Vol 48 (32) ◽  
pp. 6234 ◽  
Author(s):  
Huarong Gu ◽  
Songfeng Yin ◽  
Qiaofeng Tan ◽  
Liangcai Cao ◽  
Qingsheng He ◽  
...  
Keyword(s):  
Data Storage ◽  
Signal To Noise Ratio ◽  
Storage System ◽  
Holographic Data Storage ◽  
Signal To Noise ◽  
Data Storage System ◽  
Noise Ratio

A dynamic ionosonde design using pulse coding

1991 ◽  
Vol 69 (8-9) ◽  
pp. 1184-1189 ◽  
Author(s):  
S. Gao ◽  
J. W. MacDougall
Keyword(s):  
Solid State ◽  
Data Storage ◽  
Peak Power ◽  
Pulse Compression ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Solid State Electronics ◽  
Barker Code ◽  
Noise Ratio

A research ionosonde with capabilities for measuring drifts by the spaced-antenna method was designed and a limited prototype tested. Using a PC for much of the control and data storage functions and a small quantity of external electronics will make the instrument small and inexpensive. In particular, pulse compression techniques using a 13 bit Barker code gives an improvement in signal-to-noise ratio of about 11 dB. This allows the use of a transmitter with peak power less than a kilowatt, which is compatible with solid-state electronics.

Determination of the Best Emulsion for the Microscopy of Crystals

1981 ◽  
Vol 39 ◽  
pp. 32-33
Author(s):  
David A. Grano ◽  
Kenneth H. Downing
Keyword(s):  
Spatial Frequency ◽  
Information Transfer ◽  
Signal To Noise Ratio ◽  
Experimental Situation ◽  
Photographic Emulsion ◽  
Modulation Transfer ◽  
Signal To Noise ◽  
Frequency Space ◽  
Noise Ratio

The retrieval of high-resolution information from images of biological crystals depends, in part, on the use of the correct photographic emulsion. We have been investigating the information transfer properties of twelve emulsions with a view toward 1) characterizing the emulsions by a few, measurable quantities, and 2) identifying the “best” emulsion of those we have studied for use in any given experimental situation. Because our interests lie in the examination of crystalline specimens, we've chosen to evaluate an emulsion's signal-to-noise ratio (SNR) as a function of spatial frequency and use this as our critereon for determining the best emulsion.The signal-to-noise ratio in frequency space depends on several factors. First, the signal depends on the speed of the emulsion and its modulation transfer function (MTF). By procedures outlined in, MTF's have been found for all the emulsions tested and can be fit by an analytic expression 1/(1+(S/S0)2). Figure 1 shows the experimental data and fitted curve for an emulsion with a better than average MTF. A single parameter, the spatial frequency at which the transfer falls to 50% (S0), characterizes this curve.

Experiments in Bright-Field Imaging with Hollow-Cone Illumination

1981 ◽  
Vol 39 ◽  
pp. 226-227
Author(s):  
W. Kunath ◽  
K. Weiss ◽  
E. Zeitler
Keyword(s):  
Signal To Noise Ratio ◽  
Carbon Support ◽  
Electronic System ◽  
Optic Axis ◽  
Hollow Cone ◽  
Signal To Noise ◽  
Bright Field ◽  
Noise Ratio ◽  
Single Field ◽  
Field Imaging

Bright-field images taken with axial illumination show spurious high contrast patterns which obscure details smaller than 15 ° Hollow-cone illumination (HCI), however, reduces this disturbing granulation by statistical superposition and thus improves the signal-to-noise ratio. In this presentation we report on experiments aimed at selecting the proper amount of tilt and defocus for improvement of the signal-to-noise ratio by means of direct observation of the electron images on a TV monitor.Hollow-cone illumination is implemented in our microscope (single field condenser objective, Cs = .5 mm) by an electronic system which rotates the tilted beam about the optic axis. At low rates of revolution (one turn per second or so) a circular motion of the usual granulation in the image of a carbon support film can be observed on the TV monitor. The size of the granular structures and the radius of their orbits depend on both the conical tilt and defocus.

Information capacity and bandwidth limitations in the SEM

1989 ◽  
Vol 47 ◽  
pp. 84-85
Author(s):  
D. C. Joy ◽  
R. D. Bunn
Keyword(s):  
Signal To Noise Ratio ◽  
Critical Dimension ◽  
Information Capacity ◽  
Acquisition Time ◽  
Signal To Noise ◽  
Sem Image ◽  
Probe Size ◽  
Minimum Number ◽  
Noise Ratio ◽  
Signal Channel

The information available from an SEM image is limited both by the inherent signal to noise ratio that characterizes the image and as a result of the transformations that it may undergo as it is passed through the amplifying circuits of the instrument. In applications such as Critical Dimension Metrology it is necessary to be able to quantify these limitations in order to be able to assess the likely precision of any measurement made with the microscope.The information capacity of an SEM signal, defined as the minimum number of bits needed to encode the output signal, depends on the signal to noise ratio of the image - which in turn depends on the probe size and source brightness and acquisition time per pixel - and on the efficiency of the specimen in producing the signal that is being observed. A detailed analysis of the secondary electron case shows that the information capacity C (bits/pixel) of the SEM signal channel could be written as :

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