StackDesign Blog Electronic,Computer,AmateurRadio|Science Tue, 06 Feb 2018 14:03:04 -0800 en-AU hourly 1 StackDesign Blog 32 32 Definition some important statistical parameters Thu, 18 Jan 2018 09:23:38 +0000 Continue reading Definition some important statistical parameters]]> Today in reading book statistics i faced with some parameter  as percentile,decile and so on. i want to share here discussion.

Percentile is a important parameter, i read definition from this link.I warned that for definition below parameter data should be sorted.

percentile (or a centile) is a measure used in statistics indicating the value below which a given percentage of observations in a group of observations fall. For example, the 20th percentile is the value (or score) below which 20% of the observations may be found.


In descriptive statistics, a decile is any of the nine values that divide the sorted data into ten equal parts, so that each part represents 1/10 of the sample or population.[1] A decile is one possible form of a quantile; others include the quartile and percentile.[2]


descriptive statistics, the quartiles of a ranked set of data values are the three points that divide the data set into four equal groups, each group comprising a quarter of the data. A quartile is a type of quantile. The first quartile (Q1) is defined as the middle number between the smallest number and the median of the data set. The second quartile (Q2) is the median of the data. The third quartile (Q3) is the middle value between the median and the highest value of the data set.

Important Tip:In analysing of algorithms, mean and middle is not good parameter, some case it better consider some parameter like percentile,decile and…….

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How to run JSP on XAMPP Thu, 11 Jan 2018 14:35:27 +0000 Continue reading How to run JSP on XAMPP]]> Here we want discuss how we can run JSP code on TomCat in XAMPP.

For start TomCat You can do:

1. Download Apache Tomcat addon here.
2. Extract tomcat addon in Xampp server root directory
3. Go to C://xampp/
4. Stop all services of xampp
5. Open shell and relocate all services
6. Enable mod_jk and relocate
7. Start the services
8. In Xampp control panel you will see the tomcat service. Activate it.
9. Click on admin and enter username and password as xampp and xampp

Before start you should add below snippet to C:\xampp\tomcat\conf\tomcat-users.xml

<role rolename=”manager-script”/>
<role rolename=”manager-gui”/>
<role rolename=”manager”/>
<role rolename=”admin”/>
<user username=”xampp” password=”xampp” roles=”admin,manager,manager-gui,manager-script”/>

So with username and password as xampp you can start JSP web application.


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How Expose localhost to the world(global internet) Thu, 11 Jan 2018 08:58:09 +0000 Continue reading How Expose localhost to the world(global internet)]]> For exposing localhost NodeJS and Apache we use free tool Localtunnel, in below video you can see our local host in apache server php and node js is easy expose to to global internet.This method also work for Tomcat Java Server too.

Install Localtunnel globally (requires NodeJS) to make it accessible anywhere
npm install -g localtunnel

Start a webserver on some local port (eg http://localhost:8000) and use the command line
interface to request a tunnel to your local server:

lt –port 3000
my port app

so we can see local nodejs app and appache from internet

thank you best regards stackprogramer


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Antenna as dipole network in scattering matrix Sat, 06 Jan 2018 13:20:50 +0000 Continue reading Antenna as dipole network in scattering matrix]]> When in past i worked with SDR hardware i experimental that noise line in space is about -100dB, when i don’t amplify RF gain, when i amplify it, it is -80dB till -20dB. So other hand when i use different antenna pick value of noise is change, today i know that a antenna is a dipole network that can describe with scattering matrix.

I read from this link . so for good transmission digital video we should use RX/TX antenna.

S-parameters describe the input-output relationship between ports (or terminals) in an electrical system. For instance, if we have 2 ports (intelligently called Port 1 and Port 2), then S12 represents the power transferred from Port 2 to Port 1. S21 represents the power transferred from Port 1 to Port 2. In general, SNM represents the power transferred from Port M to Port N in a multi-port network.

A port can be loosely defined as any place where we can deliver voltage and current. So, if we have a communication system with two radios (radio 1 and radio 2), then the radio terminals (which deliver power to the two antennas) would be the two ports. S11 then would be the reflected power radio 1 is trying to deliver to antenna 1. S22 would be the reflected power radio 2 is attempting to deliver to antenna 2. And S12 is the power from radio 2 that is delivered through antenna 1 to radio 1. Note that in general S-parameters are a function of frequency (i.e. vary with frequency).

As an example, consider the following two-port network:

two  port

Fig1: Two port network

In the above Figure, S21 represents the power received at antenna 2 relative to the power input to antenna 1. For instance, S21=0 dB implies that all the power delivered to antenna 1 ends up at the terminals of antenna 2. If S21=-10 dB, then if 1 Watt (or 0 dB) is delivered to antenna 1, then -10 dB (0.1 Watts) of power is received at antenna 2.

If an amplifier exists in the circuitry, then S21 can show gain (i.e. S21 > 0 dB). This means that for 1 W of power delivered to Port 1, more than 1 W of power is received at Port 2.


In practice, the most commonly quoted parameter in regards to antennas is S11. S11 represents how much power is reflected from the antenna, and hence is known as the reflection coefficient(sometimes written as gamma:  or return loss. If S11=0 dB, then all the power is reflected from the antenna and nothing is radiated. If S11=-10 dB, this implies that if 3 dB of power is delivered to the antenna, -7 dB is the reflected power. The remainder of the power was “accepted by” or deliverd to the antenna. This accepted power is either radiated or absorbed as losses within the antenna. Since antennas are typically designed to be low loss, ideally the majority of the power delivered to the antenna is radiated. See also VSWR, which is directly related to S11.

As an example, consider the plot of S11 in the following figure:

You can see S11 and S12 a RF coil in below image , i taked it from this link.

RF coil

Fig2:RF Coil S-Parameter


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Most important parameter in SEO “Link Building Strategy” Wed, 27 Dec 2017 14:17:27 +0000 In SEO most important parameter in google ranking is Link Building Strategy. So in this blog post we discuss about how we can create a successful backlink strategy.

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Ways to be a healthier programmer Mon, 18 Dec 2017 16:05:25 +0000 Finding a way that a someone be programmer for long time is a possible, if you adhere to some point for health.Here i want to share some rule for be more happy and health in long time programming.

5 Yoga Poses Every Programmer Should Try


7 Ways to be a healthier programmer

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Tricks to Use Google Search Efficiently Thu, 07 Dec 2017 18:19:40 +0000 Continue reading Tricks to Use Google Search Efficiently]]> Here i want to share tricks that we use google search more efficiently.

Use quotes:

“stackdesign blog”

The first three results:

StackDesign Blog – Electronic,Computer,AmateurRadio|Science


stackprogramer,sp,stackdesign,استک پروگرمر,Electronic Design,Computer Science,Amateur Radio.

StackDesign Blog – StackDesign Blog


In designing circuits and systems we have to analyze behavior more than one component in time space. Toady i want to plot some time diagram and analyze some optical circuit,so i found great software that help me think more easy in circuit and system design. Continue reading Importance timing diagrams in designing …

Searching for Better Plasmonic Materials – StackDesign Blog


Nov 9, 2017 – In this post i want to discuss about what’s best material for plasmonic device application except considering graphene. I want to find a materials with low loss, high confinement and easy fabrication. From this link article,it conclude that there is not best materials for plasmonic application.

Use a hyphen to exclude words

stackdesign blog -stackdesign

The first three results:

A Full Stack Design and Brand Strategy Studio – Build Smart Grow Fast

A full stack design and brand strategy studio that works with individuals, startups and brands to create products in a digital world – Build smart grow fast.

The full stack design system – Inside Intercom


But that doesn’t seem like a great note to end a blog post. What’s more, I don’t want to believe it’s true. This very challenge is what’s uniquely interesting to me about doing large-scale design work at a growing product-oriented company. The early signs are promising. In all types of complex systems, from codebases to …

ChampKid Design -Full Stack Design & Development


ChampKid Design -Working with small businesses to build great brands, products & websites.

Use a colon to search specific sites


StackDesign Blog – Electronic,Computer,AmateurRadio|Science


stackprogramer,sp,stackdesign,استک پروگرمر,Electronic Design,Computer Science,Amateur Radio.

Importance of impedance matching and coupling … – StackDesign Blog…/importance-of-impedance-matching-and-coupling-mecha…


Aug 27, 2017 – And older story in microwave and THz or higher frequency range is finding a way that we have high effieceincy coupling. So i will discuss about mechanism coupling and phase and impedance matching.

matlab – StackDesign Blog


I before created FM example TX/RX for HackRF One in matlab simulink,Now we want to use examples of USRP to develop a example QPSK TX/RX for HackRF One in matlab Simulink. Continue reading QPSK implementation Matlab and HackRFOne. Posted on June 9, 2017 August 15, 2017 Categories Software Defined …

Find a page that links to another page

StackDesign Blog – Electronic,Computer,AmateurRadio|Science


stackprogramer,sp,stackdesign,استک پروگرمر,Electronic Design,Computer Science,Amateur Radio.

Searching for Better Plasmonic Materials – StackDesign Blog


Nov 9, 2017 – In this post i want to discuss about what’s best material for plasmonic device application except considering graphene. I want to find a materials with low loss, high confinement and easy fabrication. From this link article,it conclude that there is not best materials for plasmonic application.

RTL-SDR dongle Shows DVB-T signal SDR based? – StackDesign Blog…/rtl-sdr-dongle-how-received-dvb-t-signal-and-iq-file/


Apr 24, 2017 – Now we can from featured image of blog post it has two chip RTL2832U & E4000EQG you can find data sheet of them easily on net.You can see schematic RTL-SDR: … It is easy you can download driver for windos from this link, in linux from kernel 2.6 it is installed default. You can show playing video …

Find sites that are similar to other sites

Search Results

Walmart – Christmas Trees, Christmas Decorations & Christmas Gifts!


Every Day Low Prices on millions of online holiday and Christmas gifts with free 2-day shipping, or pick up in store and save with Pickup Discount.

Overstock: The Best Deals Online : Furniture, Bedding, Jewelry & More


Let help you discover designer brands and home goods at the lowest prices online. See for yourself why shoppers love our selection and award-winning customer service.

Macy’s – Shop Fashion Clothing & Accessories – Official Site –


Macy’s – FREE Shipping at Macy’s has the latest fashion brands on Women’s and Men’s Clothing, Accessories, Jewelry, Beauty, Shoes and Home Products.


Use Google search to do math
8 * 5 + 5
Planck’s Consant

Search for multiple words at once

Search a range of numbers

What teams have won the Stanley Cup ..2004

Use the asterisk wildcard

“Come * right now * me”

Find a specific file

*Search term here* filetype:pdf

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MMIC Vs on-chip photonic circuit Mon, 27 Nov 2017 17:08:30 +0000 In this blog post i want to compare MMIC with on-chip photonic circuit.

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Is it possible implementation Flow Control Mechanism in Gnuradio Mon, 27 Nov 2017 07:11:09 +0000 For implementation some communication protocol like bluetooth, 4G,3G and wi-fi  we need flow control mechanism.So we want to discuss can todays processors can handle these mechanisms. Soon i shared my search and result here.

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How we can create graphene sheet in Adobe Illustrator Sat, 11 Nov 2017 21:07:50 +0000 In this post i will share a video, this video describe how we can use illustrator to create a graphene sheet for article and thesis.

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Searching for Better Plasmonic Materials Thu, 09 Nov 2017 07:54:29 +0000 Continue reading Searching for Better Plasmonic Materials]]> In this post i want to discuss about what’s best material for plasmonic device application except  considering graphene. I want to find a materials with low loss, high confinement and easy fabrication.

From this link article,it conclude that there is not best materials for plasmonic application.But for some optic communication silver is good, this is not discuss about fabrication.

Fig1:Table 2 Summary of the quality factors of a number of possible low-loss plasmonic
candidate materials. The maximum value of the quality factor (up to 2.5 µm) and the
wavelength at which the maximum occurs are tabulated for each material and each of the
four applications. The quality factors at 1.5 µm (for nanophotonic applications) are also
presented. Quality factors for TO devices were calculated at the crossover frequency
where = 0.

Soon i searched and i want to conclude what’s best materials for plasmonic application.


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Relation between permittivity,refractive index and conductivity in plasmonic elements Sun, 05 Nov 2017 21:18:37 +0000 Continue reading Relation between permittivity,refractive index and conductivity in plasmonic elements]]> Here i want to discuss about relation between permittivity,refractive index and conductivity for plasmonic elements like gold,silver and graphene.

I quote definition permittivity from this link.

In electromagnetismpermittivity or absolute permittivity, usually denoted by the Greek letter ε (epsilon), is the measure of resistance that is encountered when forming an electric field in a particular medium. More specifically, permittivity describes the amount of charge needed to generate one unit of electric flux in a particular medium.


I quote definition conductivity from this link.

Electrical resistivity (also known as resistivityspecific electrical resistance, or volume resistivity) is an intrinsic property that quantifies how strongly a given material opposes the flow of electric current. A low resistivity indicates a material that readily allows the flow of electric current. Resistivity is commonly represented by the Greek letter ρ (rho). The SIunit of electrical resistivity is the ohmmetre (Ω⋅m).[1][2][3] As an example, if a 1 m × 1 m × 1 m solid cube of material has sheet contacts on two opposite faces, and the resistance between these contacts is 1 Ω, then the resistivity of the material is 1 Ω⋅m.

Electrical conductivity or specific conductance is the reciprocal of electrical resistivity, and measures a material’s ability to conduct an electric current. It is commonly represented by the Greek letter σ (sigma), but κ (kappa) (especially in electrical engineering) or γ (gamma) are also occasionally used. Its SI unit is siemens per metre (S/m) and CGSE unit is reciprocal second (s−1).


I quote definition refractive index from this link.

In optics, the refractive index or index of refractionn of a material is a dimensionless number that describes how light propagates through that medium. It is defined as


I quote definition effective refractive index from this link.

For plane waves in homogeneous transparent media, the refractive indexn can be used to quantify the increase in the wavenumber (phase change per unit length) caused by the medium: the wavenumber is n times higher than it would be in vacuum. The effective refractive indexneff has the analogous meaning for light propagation in a waveguide with restricted transverse extension: the β value (phase constant) of the waveguide (for some wavelength) is the effective index times the vacuum wavenumber:


Relation between permittivity and refractive index:

you can see proof from this link.


The relation between permittivity and conductivity

see this link.



Complex conductivity:

see this link.


 Graphene conductiviy  kubbo formula:

kubbo formula
Fig1:kubbo formula



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Importance IR light in Biosensor Sat, 04 Nov 2017 07:49:06 +0000 Continue reading Importance IR light in Biosensor]]> In biology scientists usually deal with protein, DNA and so on.Other hand biology elements radiate Infrared from themself . So this is very important that we can design IR sensor and apply them in biology fields. Graphene as a miracle material with tunability can be used important candidate  in biosensors.

Soon i will share here some data about graphene biosensors.

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Importance timing diagrams in designing circuits and systems Sun, 17 Sep 2017 15:18:12 +0000 Continue reading Importance timing diagrams in designing circuits and systems]]> In designing circuits and systems we have to analyze behavior more than one component in time space. Toady i want to plot some time diagram and analyze some optical circuit,so i found great software that help me think more easy in circuit and system design.

In this block post i want to introduce a free software and a commercial one. Timing Editor is an free software that i want to use it.It is Great you can see snap shot of it.

time editor

An other software that you should buy TimeGen, it is more pro.

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Compiling Unreal Engine Source Sat, 16 Sep 2017 16:13:19 +0000 Continue reading Compiling Unreal Engine Source]]> In this post i want to compile UNREAL ENGINE game ,It is one of most popular engine game. For compiling we use compiler microsoft Visual C++ .Net 2017 in Win8.1.This toturial can be used in compiling UNREAL in Win10.For you can compile source, you should providing some prerequisites that will describe in below.

  1. For hardware requirements :
RAM minimum 8GB
Free Space HardDrive more than 65 GB
Graphic Card Compatible with Direct X11 or 12

For more info about  DirectX see this link:

Microsoft DirectX is a collection of application programming interfaces (APIs) for handling tasks related to multimedia, especially game programming and video, on Microsoft platforms.

For seeing what DX your GPU support in command prompt or power shell type:


In dxdiag you should see that your system support DX11 or DX12.


Supportted DirectX GPU  list:



List DX11/12 GeForce/Radeon

  1. For software requirement :
  • Install SDK Win8.1 or Win10 for more info and guide see  this link.
  • Install VS2017 or VS2015 with C++ features and MFC.
  • Download UNREAL ENGINE SOURCE from this link.
  • After it, extract source, the name of source folder should be short for example my name of source folder is :”UnrealEngine” . I emphasize that using short name  otherwise you will face with an error same below:

Severity    Code    Description    Project    File    Line    Suppression State
Error        System.IO.PathTooLongException: The specified path, file name, or both are too long. The fully qualified file name must be less than 260 characters, and the directory name must be less than 248 characters.    UE4    G:\UnrealEngine\\Engine\Intermediate\ProjectFiles\EXEC    1
Error    MSB3075    The command “..\..\Build\BatchFiles\Build.bat UE4Editor Win64 Development -waitmutex” exited with code 5. Please verify that you have sufficient rights to run this command.    UE4    G:\VS2017\Common7\IDE\VC\VCTargets\Microsoft.MakeFile.Targets    44


  • Make sure that you have free space more than 65GB, otherwise you can not compile it and you will have below error.

Error    C1085    Cannot write compiler generated file: ‘G:\UnrealEngine\Engine\Intermediate\Build\Win64\UE4Editor\Development\MovieScene\Module.MovieScene.cpp.obj’: No space left on device    UE4    G:\UnrealEngine\Engine\Intermediate\Build\Win64\UE4Editor\Development\MovieScene\Module.MovieScene.cpp    1
Error    C1085    Cannot write compiler generated file: ‘G:\UnrealEngine\Engine\Intermediate\Build\Win64\UE4Editor\Development\LevelEditor\Module.LevelEditor.1_of_3.cpp.obj’: No space left on device    UE4    G:\UnrealEngine\Engine\Intermediate\Build\Win64

After you provided upper prerequisites: Do three works.


  • Open your source folder in Explorer and run Setup.bat. This will download binary content for the engine, as well as installing prerequisites and setting up Unreal file associations. On Windows 8, a warning from SmartScreen may appear. Click “More info”, then “Run anyway” to continue.A clean download of the engine binaries is currently 3-4gb, which may take some time to complete. Subsequent checkouts only require incremental downloads and will be much quicker.
  • Run GenerateProjectFiles.bat to create project files for the engine. It should take less than a minute to complete.
  • Load the project into Visual Studio by double-clicking on the UE4.sln file. Set your solution configuration to Development Editor and your solution platform to Win64, then right click on the UE4 target and select Build. It may take anywhere between 10 and 40 minutes to finish compiling, depending on your system specs.
  • After compiling finishes, you can load the editor from Visual Studio by setting your startup project to UE4 and pressing F5 to debug.
  • You can see in below video compiling UNREAL ENGINE source

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Installing Windows Software Development Kit (SDK) for Windows 8.1(Prerequisite I for UNREAL ENGINE) Tue, 12 Sep 2017 17:37:41 +0000 Continue reading Installing Windows Software Development Kit (SDK) for Windows 8.1(Prerequisite I for UNREAL ENGINE)]]> I started to compiling UNREAL ENGINE in Win8.1,my favorite game engine, So i want to share some important points in compling source UNREALengine,in this blog post we discuss about SDK Win8.1 and Win10.

SDK for windows is like SDK for android, if you work with some advance API any platform in developing source code,user of your app should install SDK in windows to can install your app.UNREAL engine is great, i select it for high power and capability in design game. Microsoft describe SDK for windows such below:

The Windows Software Development Kit (SDK) for Windows 8.1 contains headers, libraries, and tools you can use when you create apps that run on Windows operating systems. You can use the Windows SDK, along with your chosen development environment, to write Windows Store apps and desktop apps for Windows 8.1 as well as Windows 8, Windows 7, Windows Vista, Windows Server 2012, Windows Server 2008 R2, and Windows Server 2008.

For download and installing it please see link   , and run sdksetup.exe(It has volume about 1.5 Gb).By accepting terms and service, SDK will install on your windows.


Fig1: Complete Download and after  it installing  SDK  of windows 8.1 from Downloads folder

]]> 0 Review on smith chart and it’s applications Fri, 01 Sep 2017 11:30:46 +0000 Continue reading Review on smith chart and it’s applications]]> In this post we want to discuss about smith chart, in microwave transmission line we use it, for matching problems.

We want to first define and explain smith chart , i used this can download complete smith chart form this link.

The Smith chart, invented by Phillip H. Smith (1905–1987), is a graphical aid or nomogram designed for electrical and electronics engineers specializing in radio frequency (RF) engineering to assist in solving problems with transmission lines and matching circuits.The Smith chart can be used to simultaneously display multiple parameters including impedances, admittances, reflection coefficients, S n nscattering parameters, noise figure circles, constant gain contours and regions for unconditional stability, including mechanical vibrations analysis. The Smith chart is most frequently used at or within the unity radius region. However, the remainder is still mathematically relevant, being used, for example, in oscillator design and stability analysis.


Fig1:Smith chart

For proof formula and plot of smith chart you can download this useful pdf by Rick Nelson.

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Importance of impedance matching and coupling mechanism(1) Sun, 27 Aug 2017 05:28:51 +0000 Continue reading Importance of impedance matching and coupling mechanism(1)]]> And older story in microwave and THz  or higher frequency range is finding a way that we have high effieceincy coupling. So i will discuss about mechanism coupling and phase and impedance matching.

In electronic circuits,we learn first law impedance matching,when i had  a source with impedance XS and the load has impedance  Xfor high efficeicny we should had condition matching.



In microwave ad comunication systems, we may face with some loads can not satisfy this condition,so we should use some extra circuit that make coupling effieciecny with out changing paramter loads.

Single Stub Matching:

There are two design parameters for single stub matching:

  • ‰ The location of the stub with reference to the load dstub
  • ‰ The length of the stub line Lstub

Any load impedance can be matched to the line by using single stub technique. The drawback of this approach is that if the load is changed, the location of insertion may have to be moved.for more info please see this file handbook.

single stub matching

Fig1:single stub matching

The transmission line realizing the stub is normally terminated by a
short or by an open circuit. In many cases it is also convenient to
select the same characteristic impedance used for the main line,
although this is not necessary. The choice of open or shorted stub
may depend in practice on a number of factors. A
short circuited
stub is
less prone to leakage of electromagnetic radiation and is
somewhat easier to realize. On the other hand, an
open circuited
stub may be
more practical for certain types of transmission lines,
for example microstrips where one would have to drill the insulating
substrate to short circuit the two conductors of the line.


Since the circuit is based on insertion of a parallel stub, it is more convenient to work with admittances, rather than impedances.stub matching admittance

Fig2:stub matching admittance

For proper impedance match:


In order to complete the design, we have to find an appropriate location for the stub. Note that the input admittance of a stub is always imaginary (inductance if negative, or capacitance if positive):
Ystub = jBstub

A stub should be placed at a location where the line admittance has real part equal toY0:


For matching, we need to have

Bstub = – B(dstub )

Depending on the length of the transmission line, there may be a
number of possible locations where a stub can be inserted for
impedance matching. It is very convenient to analyze the possible
solutions on a Smith chart.


stub matching

Fig3:YA in stub matching

So in the next post we with same title we will discuss about other mechanism mathcing.

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3D Contour Farfields in Microwave and Light Devices Wed, 23 Aug 2017 13:38:30 +0000 Continue reading 3D Contour Farfields in Microwave and Light Devices]]> In this here we want to discuss about farfields in microwave and light devices.farfield is a polar of fileds or power that is used in antenna design.

I so far faced with farfields,today i want to discuss about it and i learn more about it, in CST Microwace and Lumerical you can see this polar contour.So i searched some to find a defintion about farfields.

The far field of the feed antenna can be used as a source in the reflector dish simulation. Both models can be simulated with appropriate solvers.


Fig1: Using farfeilds plot in antenna optimization

So old puzzle in practical microwave problem is coupling.every more confined power and field in direction antenna can increase more efficeiency and less loss. you can download this pdf for  more info.

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Selectivity and sensitivity in SDR Hardwares Sun, 20 Aug 2017 07:00:33 +0000 Continue reading Selectivity and sensitivity in SDR Hardwares]]> Finally we worked on RTL-SDR and HackRF One and USRP in practical test and different moudlation like GFSK,DVB-T,ATSC,OFDM,DMR.With all of them we can see spectrum, it is not final purpose, we emphasize ,purpose is data in digital radio communication.So which SDR hardware can handle  data extracting with different moudation and protocols like GSM or even LTE and so on.

So we want to how we can select best sdr hardware according our purpose and our budget.So please for buy new SDR check these important paramters.We can define sensitiviy with helping this link.

The sensitivity of an electronic device, such as a communications system receiver, or detection device, such as a PIN diode, is the minimum magnitude of input signal required to produce a specified output signal having a specified signal-to-noise ratio, or other specified criteria.

Sensitivity is sometimes improperly used as a synonym for responsivity.[citation needed][1]

The sensitivity of a microphone is usually expressed as the sound field strength in decibels (dB) relative to 1 V/Pa (Pa = N/m2) or as the transfer factor in millivolts per pascal (mV/Pa) into an open circuit or into a 1 kilohm load.[citation needed]

The sensitivity of a loudspeaker is usually expressed as dB / 2.83 VRMS at 1 metre.[citation needed] This is not the same as the electrical efficiency; see Efficiency vs sensitivity.

The sensitivity of a hydrophone is usually expressed as dB re 1 V/µPa.[citation needed]

Sensitivity in a receiver is normally defined as the minimum input signal S i {\displaystyle S_{i}} S_{i} required to produce a specified signal-to-noise S/N ratio at the output port of the receiver and is defined as the mean noise power at the input port of the receiver times the minimum required signal-to-noise ratio at the output of the receiver:

S i = k ( T a + T r x ) B ⋅ S o N o {\displaystyle S_{i}=k(T_{a}+T_{rx})B{\cdot }{\frac {S_{o}}{N_{o}}}} S_{i}=k(T_{a}+T_{{rx}})B{\cdot }{\frac {S_{o}}{N_{o}}}


S i {\displaystyle S_{i}} S_{i} = sensitivity [W]
k = Boltzmann’s constant
T a {\displaystyle T_{a}} T_{a} = equivalent noise temperature in [K] of the source (e.g. antenna) at the input of the receiver
T r x {\displaystyle T_{rx}} T_{{rx}} = equivalent noise temperature in [K] of the receiver referred to the input of the receiver
B = bandwidth [Hz]
S o N o {\displaystyle {\frac {S_{o}}{N_{o}}}} {\frac {S_{o}}{N_{o}}} = Required SNR at output [-]

Because receiver sensitivity indicates how faint an input signal can be to be successfully received by the receiver, the lower power level, the better. Lower power for a given S/N ratio means better sensitivity since the receiver’s contribution is smaller. When the power is expressed in dBm the larger the absolute value of the negative number, the better the receive sensitivity. For example, a receiver sensitivity of −98 dBm is better than a receive sensitivity of −95 dBm by 3 dB, or a factor of two. In other words, at a specified data rate, a receiver with a −98 dBm sensitivity can hear signals that are half the power of those heard by a receiver with a −95 dBm receiver sensitivity.we too bring here definition selectivity from this link.

Selectivity is a measure of the performance of a radio receiver to respond only to the radio signal it is tuned to (such as a radio station) and reject other signals nearby in frequency, such as another broadcast on an adjacent channel.

Selectivity is usually measured as a ratio in decibels (dBs), comparing the signal strength received against that of a similar signal on another frequency. If the signal is at the adjacent channel of the selected signal, this measurement is also known as adjacent-channel rejection ratio (ACRR).

Selectivity also provides some immunity to blanketing interference.

So we here introduce some of important paramters in sensitivity and selectivity.

  • Frequency precision( Oscillator Precision )

SDR hardware has a paramter that is called Oscillator Precision ,only you should buy a SDR hardware with 1ppm or more less, In case over 1pmm, i advise do not wasting your money.

  • ADC bit resolution

Buying a SDR with 8bit ADC,is wasting money.i advise  that once  buy a high quality SDR Hardware  instead buy some SDR,that every time you have to switch high quality SDR hardware, So You should buy SDR hardware with 12bit or better more than 12 bit like blade RF (for low cost case) and USRP for (high cost case).

  • USB3

I strongly advice buy a SDR with USB3, USB2 in higher and complicated protcol is not good and ideal result.

  • Programmable Logic Gates

For FPGA filter idealization, i advise use a SDR that is in FPGA with more than 40k,For example HackRF one use CPLD ,So it is very weak in receiving.

  • Output pwoer

Output power is not important,because in practical we should design power amplifier, but it is good in range 10dB.

So here i share some popular SDR hardware that you can more info from this link.

HackRF One Ettus B200 Ettus B210 BladeRF x40 RTL-SDR LimeSDR
Frequency Range 1MHz-6GHz 70MHz-6GHz 70MHz-6GHz 300MHz-3.8GHz 22MHz-2.2GHz 100kHz-3.8GHz
RF Bandwidth 20MHz 61.44MHz 61.44MHz 40MHz 3.2MHz 61.44MHz
Sample Depth 8 bits 12 bits 12 bits 12 bits 8 bits 12 bits
Sample Rate 20MSPS 61.44MSPS 61.44MSPS 40MSPS 3.2MSPS 61.44MSPS (Limited by USB 3.0 data rate)
Transmitter Channels 1 1 2 1 0 2
Receivers 1 1 2 1 1 2
Duplex Half Full Full Full N/A Full
Interface USB 2.0 USB 3.0 USB 3.0 USB 3.0 USB 2.0 USB 3.0
Programmable Logic Gates 64 macrocell CPLD 75k 100k 40k (115k avail) N/A 40k
Chipset MAX5864, MAX2837, RFFC5072 AD9364 AD9361 LMS6002M RTL2832U LMS7002M
Open Source Full Schematic, Firmware Schematic, Firmware Schematic, Firmware No Full
Oscillator Precision +/-20ppm +/-2ppm +/-2ppm +/-1ppm ? +/-1ppm initial, +/-4ppm stable
Transmit Power -10dBm+ (15dBm @ 2.4GHz) 10dBm+ 10dBm+ 6dBm N/A 0 to 10dBm (depending on frequency)
Price $299 $686 $1,119 $420 ($650) ~$10 $299 ($289 pre-order)

I think BladeRF for ( low cost case) and USRP for (high cost  case ) other SDR hardware is not ideal for data exctracting.



Fig1:BladeRFx40 as low cost case


Fig2:USRPN210 as high cost case

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