Glossary of DSA Related Terms and Acronyms
Hardware: Modular Instruments>>Dynamic Signal Acquisition and Analysis (DSA)
Problem: Where can I find a Glossary of DSA (Dynamic Signal Analysis) related terms and acronyms?
Solution: The following is a brief Glossary of the most commonly used DSA related terms and acronyms. Additional terms not referenced here can be found in the
NI Developer Zone.
- A/D
- Aliasing
- Anti-aliasing filter
- D/A
- DAQ
- Decibel (dB)
- DIO
- DSA
- DSP
- Dynamic Range
- FFT
- g: Unit for measuring acceleration. One g = 9.81 m/s2, the acceleration due to gravity at the surface of Earth.
- Integrated Circuit Piezolelectric
- JTFA: Joint Time-Frequency Analysis
- Noise
- NVH
- Nyquist frequency
- Octave
- Order: Harmonic of the rotational speed of rotating machinery. As an example, in the case of the shaft rotating at 6,000 rpm, the first order component occurs at a frequency of 100 Hz (6,000/60), whereas the third order component would occur at a frequency of 300 Hz.
- Order analysis
- Order tracking
- PCI (Peripheral Component Interconnect)
- PCMCIA (Personal Computer Memory Card International Association)
- Piezoelectric: A property exhibited by certain materials that generate an electrical voltage when deformed under the application of a force. Conversely, when an electrical voltage is applied across a piezoelectric material, the material deforms. The piezoelectric property of materials is used in transducers that convert acceleration (or force) into electrical signals, and vice versa. See also,
Accelerometer, Integrated Circuit Piezolelectric, and Piezoelectric Microphone.
- Sensor: A device that converts a physical stimulus (such as force, sound, pressure, motion) into a corresponding electrical signal. Also known as a transducer.
- Signal to Noise Ratio (SNR, S/N)
- Spectral leakage: A phenomenon whereby the measured spectral energy appears to leak from one frequency into other frequencies. It occurs when a sampled waveform does not contain an integral number of cycles over the time period during which it was sampled. The technique used to reduce spectral leakage is to multiply the time-domain waveform by a "window" function (see also Windowing).
- Spectrogram: A three-dimensional intensity plot displaying the amplitude of spectral components as a function of both time and frequency. Usually the horizontal and vertical axes correspond to time and frequency, whereas the intensity corresponds to the amplitude. See also, Gabor Spectrogram.
- Virtual Instrumentation: A layer of software and/or hardware added to a general-purpose computer in such a fashion that users can interact with the computer as though it was their own custom-designed traditional electronic instrument. See also, VI.
- Waterfall
- Wavelet analysis: Unlike Fourier analysis, in which you compare the signal with sine and cosine functions, the so-called wavelet analysis applies wavelets (pieces of waveforms) to measure the data samples. Because the wavelets are concentrated in a short time period, the resulting analysis not only gives the frequency information, but also provides the corresponding time information. In contrast to JTFA, the time-frequency resolution of the wavelet analysis is varied. That is, it has high-frequency resolution and low time resolution at low frequencies, and low-frequency resolution and high time resolution at high frequencies. So, the wavelet analysis can also be considered as the sort of constant Q analysis. However, constant Q analysis does not possess the reconstruction property as does wavelet analysis. See also, Wavelet.
- White noise
- Windowing: The technique used to reduce spectral leakage by multiplying the time-domain waveform by a "window" function. The process of windowing reduces the amplitudes of discontinuities at the edges of a waveform, thereby reducing spectral leakage. Note that if the waveform contains an integral number of cycles, there is no spectral leakage. See also, Window.
Related Links: NI Developer Zone: Sensors Dynamic Signal Analyzers (DSA) Support Developer Zone Tutorial: Sensor Terminology
Attachments:
Report Date: 11/08/2002
Last Updated: 09/27/2007
Document ID: 2R785TK8
