Hasznos
link-ek
| http://www.daqarta.com Daqarta!
(Data AcQuisition And Real-Time
Analysis
system) is a shareware, POWERFUL, EDUCATIONAL
(uses built-in virtual source, no board needed) digital
oscilloscope / spectrum(FFT) analyzer ... Plus, friendly
minimal-math tutorial included.
"Real-time FFT spectrum / color spectrogram / waveform display on any DOS system, using popular sound cards or laboratory data acquisition boards" |
 http://www.dadisp.com
DADiSP (standing for Data Analysis and Display)
provides an intuitive, spreadsheet-like, icon- and menu-driven environment
for displaying and analyzing data. DADiSP's data management and display
capabilities allow users to work with data series, matrices, images, waveforms,
and signals.
The flexible graphics-based spreadsheet contains hundreds of built-in functions to perform graphical data analysis, mathematical and statistical analysis, data management, and FFT analysis. DADiSP enables users to build complex programs or analysis chains without programming, simply by linking functions through a series of dynamic, interactive analysis cells. As new data is entered, or functions changed, all cells recalculate and update automatically, exactly as a typical spreadsheet, only graphically.  The
FREE Student Edition (2.8
MB, self-extracting archive of zipped installation files) is a 9-windowed,
menu-driven spreadsheet, running under Microsoft
Windows, accepting data series of 8192 points,
and includes on-line documentation to answer all your questions.
Pop-up menus and icon buttons enable the user to quickly build sophisticated
analysis chains with merely the click of a mouse, incorporating functions
for signal arithmetic and calculus, signal editing, waveform generation,
peak finding, Fourier analysis, matrix manipulation, graphing
and plotting, custom menu creation, text, and annotation. Customize
functions with DADiSP's macro facility and Series Processing Language (SPL). |
| http://www.evaluationengineering.com/pctest/pcenterance.htm PC-Based Test: A User's Resource |
- Time Domain vs. Frequency Domain This spectral simulation is an interactive Java applet.
The three-dimensional plot of frequency, amplitude and time that shows the relationship between the time and frequency domains. It does so by looking at the fundamental of a sine wave - and up to three harmonics - as they are formed by rotating vectors.
An oscilloscope is a device that views a waveform's voltage vs. time. It is the most general-purpose tool we have to gain insight into how a circuit or signal is performing. This plot simulates an oscilloscopes view. Look at the diagram from the lower left. What you see is an oscilloscopes view of the waveform (amplitude vs. time), which is really the vector sum of all of the sinusoidal components vs. time.
A spectrum analyzer is another visual analysis device. The spectrum analyzer works in the frequency domain. It displays the amplitude of the individual frequency components vs. frequency. If you choose "4 harmonics" and look at the 4 waveforms from a vantage point at the lower right of the drawing, you essentially see what a spectrum analyzer would display (amplitude vs. frequency). Depending upon the type of spectrum analyzer chosen, the phase relationships of the frequency components may or may not be preserved. Looking from the lower left, you get an oscilloscope's view of the waveform (amplitude vs. time).
- Java Applet for Fourier Series
- Gibbs Phenomenon with Java applets
- Java applet for Interference of Sinusoidal Waveforms
- Basic Function of an Oscilloscope This java applet shows the basic functions of an oscilloscope. Click within one of the knobs and drag the mouse button clockwise/countercolockwise to change values for Time/Div, Volt/Div , yOffset and xOffset.
- Oscilloscope's operation animation
- Digital Oscilloscope Uses PC Sound Card for Input Oscilloscope for Windows is a Windows application that converts your PC into a powerful dual-trace oscilloscope. Oscilloscope uses your PC's sound card as an Analog-to-Digital Converter (ADC) to digitize any input waveform (speech, music, electric signal, etc.) and then presents it on the monitor in real time, allowing the user to control the display in the same way as on a conventional "standalone" scope, for example change gain, timebase or plot Lissajous patterns. (Spectrum analyzer (realtime, built-in), 20 kHz bandwidth.)
- Lissajous Curves ( hazai vizeken: TTK Matematikai Intézet - /St. Andrews-i Egyetem Matematikai Intézet tükör/ - matematika-történeti archívum, Lissajous görbe és ennek interaktív kísérletezésre alkalmas formája)
- Spectral Animations In engineering school, we learn to represent sinusoidal wave forms with vectors. But a paper textbook can't do justice to a time-varying vector. These animated Spectral Simulations add life to vectors and help the student visualize how time-varying signals combine to make a waveform.
- Superheterodyne Spectrum Analyzer This spectral simulation is an interactive Java applet.
- FFT Spectrum Analyzer Demo applet simulates the operation of an FFT spectrum analyzer (input: Sine, Cosine, Square, Triangular or Sawtooth, optionally add a DC and/or noise; AAF: on/off; fs = 8 kHz fixed; N = 32 ... 512 in a power of 2; data window: Rectangular, Bartlett, Hanning, Hamming or Blackman; magnitude scale: LINear)
The most common type of spectrum analyzer, especially at high radio frequency and microwave frequencies is the (super)het SpA, shown in the simplified block diagram. It operates in a fashion similar to a super(het) AM radio receiver, with the output in this case going to a CRT display rather than a speaker. The simulation is for an all-analog instrument.
- SampleMania explore sampling and reconstruction with an interactive Java applet (and more ...)
- Sampling Rate and Aliasing Demos explore the aliasing effect (wagon wheel, light wheel, sampling a waveform)
- Anti-Aliasing Filter picking the right low pass (anti-aliasing) filter for your data acquisition system may not be as straightforward as it appears ... The good news it that there are a variety of tools available to get you through the logistics (or painful calculations) of implementing discrete low pass filters. For instance, Microchip Technology, Inc has an interactive program called FilterLab that can be downloaded ( www.microchip.com development tools - analog/interface tools - FilterLab filter design SW) ... This interactive article will ultimately go through the process of selecting the correct anti-aliasing filters for three applications.
These circuits cover the most common classes of filter design problems. The first circuit requires a filter for a DC voltage signal. This type of application challenges the filter’s ability to reject noise. The second circuit requires an anti-aliasing filter that has the ability to respond quickly to step responses. The selection of this filter depends heavily on time domain issues. The third application circuit requires a filter that has the combination of good step response as well as good high frequency noise reduction.
- NIST Time and Frequency Division
- Vernier This java applet shows you how to read a vernier. Just click the show checkbox and drag the ruler (left/right).
Megjegyzés: a mechanikai "tolómérõ" mûködéséhez hasonlóan interpolál pl. a nagyfelbontású ("digitális interpoláló") idõmérõ (noniusz - elv)
- Histogram Explorer a tool (Java applet window) for understanding histograms and their statistics
- The Quincunx shown in the animation below is a "statistical" experiment leading to what is called a normal distribution - a key concept in statistics, describing a wide range of statistics where there is random behaviour
e-mail: papay@hit.bme.hu
