Using of Downsampling Theory Base on Shannon in Software Radio

2014 ◽  
Vol 1049-1050 ◽  
pp. 1526-1530
Author(s):  
Mei Li
Keyword(s):  
Software Radio ◽  
Sampling Technique ◽  
Digital Down Converter ◽  
Band Pass ◽  
Theory Base

The theory of down sampling technique base on band-pass sampling and using inSoftware radio is introduced in this paper. We provided an achievement method ofNumerically controlled oscillator (NCO) in digital down converter of down samplingtechnique in the article.

scholarly journals Band-Pass Sampling in High-Order BOC Signal Acquisition

2018 ◽  
Vol 8 (11) ◽  
pp. 2226 ◽  
Author(s):  
Zhijun Liu ◽  
Baiyu Li ◽  
Xiangwei Zhu ◽  
Lixun Li ◽  
Guangfu Sun
Keyword(s):  
Computational Complexity ◽  
Sampling Technique ◽  
Global Navigation Satellite Systems ◽  
Signal Acquisition ◽  
Binary Offset Carrier ◽  
Satellite Systems ◽  
Sampled Signal ◽  
Band Pass ◽  
Global Navigation Satellite ◽  
High Computational Complexity

The binary offset carrier (BOC) modulation, which has been adopted in modern global navigation satellite systems (GNSS), provides a higher spectral compatibility with BPSK signals, and better tracking performance. However, the autocorrelation function (ACF) of BOC signals has multiple peaks. This feature complicates the acquisition process, since a smaller time searching step is required, which results in longer searching time or greater amounts of hardware resources. Another problem is the high Nyquist frequency, which leads to high computational complexity and power consumption. In this paper, to overcome these drawbacks, the band-pass sampling technique for multiple signals is introduced to BOC signals. The sampling frequency can be reduced significantly. Furthermore, the ACF of the sampled signal has only two secondary peaks, so that the code phase can be searched with a larger searching step. An acquisition structure base on dual-loop is proposed, to completely eliminate the ambiguity and compensate the subcarrier Doppler. The acquisition performance and the computational complexity are also analysed.

scholarly journals A software-radio front-end for microwave applications

2003 ◽  
Vol 1 ◽  
pp. 201-205
Author(s):  
M. Streifinger ◽  
T. Müller ◽  
J.-F. Luy ◽  
E. M. Biebl
Keyword(s):  
Signal To Noise Ratio ◽  
Schottky Diodes ◽  
Sampling Rate ◽  
Software Radio ◽  
Sampling Technique ◽  
Wide Band ◽  
Sigma Delta ◽  
Direct Sampling ◽  
Band Limited ◽  
Sigma Delta Adc

Abstract. In modern communication, sensor and signal processing systems digitisation methods are gaining importance. They allow for building software configurable systems and provide better stability and reproducibility. Moreover digital front-ends cover a wider range of applications and have better performance compared with analog ones. The quest for new architectures in radio frequency front-ends is a clear consequence of the ever increasing number of different standards and the resulting task to provide a platform which covers as many standards as possible. At microwave frequencies, in particular at frequencies beyond 10 GHz, no direct sampling receivers are available yet. A look at the roadmap of the development of commercial analog-to-digital-converters (ADC) shows clearly, that they can neither be expected in near future. We present a novel architecture, which is capable of direct sampling of band-limited signals at frequencies beyond 10 GHz by means of an over-sampling technique. The wellknown Nyquist criterion states that wide-band digitisation of an RF-signal with a maximum frequency ƒ requires a minimum sampling rate of 2 · ƒ . But for a band-limited signal of bandwidth B the demands for the minimum sampling rate of the ADC relax to the value 2 · B. Employing a noise-forming sigma-delta ADC architecture even with a 1-bit-ADC a signal-to-noise ratio sufficient for many applications can be achieved. The key component of this architecture is the sample-and-hold switch. The required bandwidth of this switch must be well above 2 · ƒ . We designed, fabricated and characterized a preliminary demonstrator for the ISM-band at 2.4 GHz employing silicon Schottky diodes as a switch and SiGe-based MMICs as impedance transformers and comparators. Simulated and measured results will be presented.

RF Front-End Design and Implementation Based on Application of Software Radio

2014 ◽  
Vol 577 ◽  
pp. 957-960
Author(s):  
De Min Pan ◽  
Wen Jing Shang ◽  
Nan Wang ◽  
Rublev Victor
Keyword(s):  
Radio Frequency ◽  
Software Radio ◽  
Intermediate Frequency ◽  
Experimental Results ◽  
Radio Structure ◽  
Design And Implementation ◽  
Front End ◽  
Rf Front End ◽  
Band Pass

Digitizing architecture of band-pass sampling at IF(Intermediate Frequency) is a kind of software radio structure of high practical value. One kind of application in the digitizing architecture of band-pass sampling at IF of RF (Radio Frequency) front-end hardware is designed in this paper. The experimental results show that this kind of RF front-end has great practical value and research significance.

Research and Design of Digital down Converter Based on Software Defined Radio

2014 ◽  
Vol 513-517 ◽  
pp. 1803-1806
Author(s):  
Wen Bin Wang ◽  
Dao Yuan Liu ◽  
Yu Qin Yao
Keyword(s):  
Software Defined Radio ◽  
Orthogonal Transformation ◽  
Software Radio ◽  
Digital Signal ◽  
Development Trend ◽  
Sampling Theorem ◽  
Transformation Theory ◽  
Processing Theory ◽  
Digital Down Converter ◽  
Cic Filter

This paper makes a brief introduction on the current development trend of software radio and digital down converter status. The basic theoretical knowledge: Band-pass sampling theorem, digital signal orthogonal transformation theory, multi-rate signal processing theory. Based on these theories, use MATLAB complete the design and verification of mixing module, the extraction module (CIC filter, half-band filter and FIR filters), finally verify the correctness of the design, and implement DDC.

DDC Design for Multi-Frequency Receiver Based on RF Sampling

2014 ◽  
Vol 651-653 ◽  
pp. 413-416
Author(s):  
Chun Yang Han ◽  
Wei Sun ◽  
Gui Xin Han
Keyword(s):  
Sampling Rate ◽  
Software Radio ◽  
Sampling Technique ◽  
High Sensitivity ◽  
Local Oscillator ◽  
High Signal ◽  
High Sampling Rate ◽  
Stable Performance ◽  
Down Conversion ◽  
Rf Sampling

Multi-frequency receivers rely on GNSS to achieve high-precision positioning, high sensitivity and other functions. GNSS signal frequencies are widely distributed around 1.1GHz to 1.6GHz. Good performance RF front-end receiver will provide high-quality acquisition and tracking environment, reducing the SER to ensure CNR. RF sampling technique is widely used in software radio for its simple structure, flexible configuration, and other advantages, but rarely used in satellite navigation, because the high signal carrier frequency and sampling rate, down-conversion based on RF sampling becomes a big challenge. So, to solve the problems of widely distributed we design three signal bands, using different local oscillator to implement signal down-conversion; to solve the problems of high sampling rate, we propose a down-conversion program of using a cascade of CIC filter’s ployphase and FIR compensation filter. Through the simulation of MATLAB after tracking tests, analysis of CNR and other indicators of programs. Ultimately, we implement the program with Verilog language on the multi-frequency GNSS receiver. The results show that this scheme can achieve digital down-conversion and stable performance of tracking loop with less consumption of resources.

The structure of membranes and membrane proteins embedded in amorphous ice

1992 ◽  
Vol 50 (1) ◽  
pp. 432-433
Author(s):  
Uwe Lücken ◽  
Joachim Jäger
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Membrane Proteins ◽  
Phase Transition Temperature ◽  
Lipid Vesicles ◽  
Freezing Stress ◽  
Amorphous Ice ◽  
Different Temperatures ◽  
Band Pass ◽  
Lipid Polymorphism

TEM imaging of frozen-hydrated lipid vesicles has been done by several groups Thermotrophic and lyotrophic polymorphism has been reported. By using image processing, computer simulation and tilt experiments, we tried to learn about the influence of freezing-stress and defocus artifacts on the lipid polymorphism and fine structure of the bilayer profile. We show integrated membrane proteins do modulate the bilayer structure and the morphology of the vesicles.Phase transitions of DMPC vesicles were visualized after freezing under equilibrium conditions at different temperatures in a controlled-environment vitrification system. Below the main phase transition temperature of 24°C (Fig. 1), vesicles show a facetted appearance due to the quasicrystalline areas. A gradual increase in temperature leads to melting processes with different morphology in the bilayer profile. Far above the phase transition temperature the bilayer profile is still present. In the band-pass-filtered images (Fig. 2) no significant change in the width of the bilayer profile is visible.

DNA sequence mapping in interphase and metaphase chromosomes by fluorescence in situ hybridization

1992 ◽  
Vol 50 (1) ◽  
pp. 496-497
Author(s):  
Barbara Trask ◽  
Susan Allen ◽  
Anne Bergmann ◽  
Mari Christensen ◽  
Anne Fertitta ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Dna Sequence ◽  
Dna Sequences ◽  
Dual Band ◽  
Nick Translation ◽  
Metaphase Chromosomes ◽  
Band Pass ◽  
Texas Red ◽  
Fluorescent Spot

Using fluorescence in situ hybridization (FISH), the positions of DNA sequences can be discretely marked with a fluorescent spot. The efficiency of marking DNA sequences of the size cloned in cosmids is 90-95%, and the fluorescent spots produced after FISH are ≈0.3 μm in diameter. Sites of two sequences can be distinguished using two-color FISH. Different reporter molecules, such as biotin or digoxigenin, are incorporated into DNA sequence probes by nick translation. These reporter molecules are labeled after hybridization with different fluorochromes, e.g., FITC and Texas Red. The development of dual band pass filters (Chromatechnology) allows these fluorochromes to be photographed simultaneously without registration shift.

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