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NoiseCheck

NoiseCheck

Description

NoiseCheck is a cost-effective software-based system for measuring noise and vibration of motors, fans, gears, bearings, pumps and other electromechanical products.

NoiseCheck ‘listens’ to the product and quantifies both the level and frequency of the noise to ensure that they are within pre-set limits. It can simultaneously carry out time domain analysis for transient noise and frequency domain analysis for steady-state noise, replicating the human ear’s ability to hear both types of noise at once. It offers many advantages over human listeners, such as detailed fault detection analysis, clearly displaying the type and magnitude of the fault, automatic saving of data for later analysis, automated record keeping / part traceability, and can easily be integrated as part of an automated production line. NoiseCheck can also be used in the R&D lab to aid in the design of quiet products.

Operation is simple. The device under test is powered up, either using DC connect, a power supply that integrates with NoiseCheck for automated testing, (for devices requiring a power supply less that 10V DC) or an external source, and Noisecheck records the noise it produces via a microphone. If it is preferable to measure vibration rather than sound, an accelerometer or a laser vibrometer may be used instead of the microphone. For testing run up/down and variable speed products such as some fans, DC Connect can be programmed via NoiseCheck to ramp voltage up/down.

Recording is started either manually (remotely) by an operator, or triggered at a given level. A spectrum analysis is performed on the recorded noise, and it is compared to pre-set limits which may either be based on a reference unit, or entered manually. NoiseCheck offers two options for analyzing the signal from the DUT. The Scope-FFT includes a spectrum analyzer for measuring high resolution FFTs in the frequency domain and an Oscilloscope for measuring in the time domain. The Real Time Analyzer measures in the frequency domain by analyzing user-selectable 1/nth octave bins. The Spectrum analyzer offers high frequency resolution, and the real time analyzer offers nth octave resolution (like the human ear) and is less sensitive to fluctuations in rotation speed. Both instruments offer selectable averaging parameters to suit the application. The comparison of actual noise to pre-set limits or a reference unit is used to generate an output, ranging from a simple pass/fail signal, to a full failure mode analysis and report.

Customized test sequences are easy to develop using a simple point-and-click interface that enables complex tests to be built in a flow chart like format. Pre-programmed or user defined options are simply selected for each step in the test procedure, e.g. input voltage, recording trigger, recording time, type of analysis, output, data recording, etc.

Data is output in a variety of ways, ranging from a simple comparison to a reference unit with a PASS/FAIL indication for the production line operator, to customized reports or writing of complete test results to databases such as Microsoft® Access, SQL or Oracle® for parts traceability archiving, data-mining or report writing. NoiseCheck also features an extensive statistical analysis toolbox which can be used for Gage R&R studies including, max, min, mean, standard deviation, yield, Cpk, and Best Fit to Average.

NoiseCheck 14 Technical Specifications

Virtual Audio Test Bench

  • Run multiple instances of each virtual instrument simultaneously

Multimeter

  • Average, Maximum, Minimum (RMS and Peak) levels with overload indication
  • Linear and Exponential averaging time (Fast, Slow, and user-defined)
  • A, B, C and user-defined weightings
  • Selectable Max/Min limits with Pass/Fail indication

Oscilloscope

  • Triggering
  • Delta cursor
  • Selectable graphical zoom
  • View spectrum of current waveform

Spectrum Analyzer

  • FFT with arbitrary number of spectral lines (only limited by computer speed and memory)
  • Hanning, Hamming, Blackman-Harris, Exact Blackman, Blackman, Flat top, 4 Term Blackman-Harris, and 7 Term Blackman-Harris windows
  • Triggering
  • Complex or power averaging
  • Average, Maximum, Minimum level with overload and real time indicators
  • Selectable averaging time (Linear & Exponential)
  • A, B, C and user-defined weightings
  • Pure tone frequency and amplitude extraction with “snap to max”
  • Delta and Harmonic cursor with THD readout
  • Selectable graphical zoom
  • View last waveform of current spectrum
  • Save to memory of current spectrum

Real-Time Analyzer

  • 1/1, 1/3, 1/6, 1/12, 1/24 octave filters with true digital recursive filters
  • Average, Maximum, Minimum level with overload and real time indicators
  • A, B, C and user defined weighting filters
  • Complies with ANSI S1.11 and IEC 1260
  • Linear and Exponential averaging time (Fast, Slow, and user-defined)

NoiseCheck Step Editors

Hardware

  • Windows Multimedia devices including sound cards with ASIO drivers (PCI, PCMCIA, USB, Fire wire), Bluetooth, and VoIP.
  • NI DAQmx data acquisition cards including NI 4461
  • Calibration and settings including sampling rate, bit depth, analog or digital audio, maximum voltage, and alias free frequency limit.
  • I/O cards for TTL relay control
  • Computer interfaces control with RS-232, GPIB (IEEE-488), footswitch and buzzer.
  • AmpConnect™ and DC Connect™ configuration
  • Multichannel configuration with table view of channels

Calibration

  • Measure Input sensitivities for transducers, amplifiers, and signal conditioning devices using built-in routines and store calibration history
  • Calibration with external, absolute source including acoustic, vibration, or voltage.
  • User-defined physical units (e.g. Pa, V, G, etc.)
  • Complex Equalization (amplitude and phase) of input devices (e.g. microphones).
  • Import of EQ/Correction curves for transducers

Messages

  • Message steps initiated based on Pass/Fail conditions
  • Display text message in local language, input numeric values, Yes/No dialog
  • Digital I/O
  • IEEE-488 and RS-232
  • AmpConnect™ set up

Acquisition

  • Record, any combination of Multimeter, RTA, and FFT
  • Capture response time waveform as a WAV file
  • Simultaneous acquisition using up to 64 channels
  • Triggered record
  • Record level monitoring

Analysis

Time

  • Impulse Response
  • Auto-Correlation
  • Cross-Correlation
  • Time Envelope
  • Loose particle detection
  • Automatic delay compensation

Frequency

  • FFT & DFT (any size), and Nth octave resolution
  • Hann, Blackman-Harris and Flat Top windows
  • Auto-spectrum & Cross-spectrum
  • Spectral Scaling: RMS or Power Density
  • Frequency and phase response including harmonics
  • Complex or power averaging
  • Relative or absolute response
  • Coherent Output Power
  • Coherence & Non-Coherence
  • Signal-to-Noise Ratio
  • Measurement Confidence
  • Impedance

Algorithms

  • Broadband RMS to measure unfiltered level of an AC or DC signal
  • Average FFT Spectrum
  • Time Selective Response (‘Farina” method) to measure free-field and impulse response of fundamental AND harmonics. This includes deconvolved time response and choice of time windows.
  • Heterodyne to measure frequency and phase response with optimal accuracy
  • HarmonicTrak™ Algorithm tracks level and phase of any user-selected harmonics including sub-harmonics or intermodulation products; no limit to number of harmonics
  • Loose particle detection
  • Multitone
  • RTA Spectrum & frequency response
  • Transfer function between any two channels

Distortion

  • THD and Rub & Buzz
  • Normalized THD and Rub & Buzz distortion (harmonics compared to amplitude of fundamental at measured frequency)
  • Perceptual Rub & Buzz in phons
  • THD + Noise
  • Intermodulation or Difference Frequency
  • Difference Frequency
  • Non-Coherent Distortion

Recall

  • Automatically recall data or results

Post-processing

  • Complex math: Addition, subtraction, multiplication, division, offset by constant (X, Y, or Z dimensions), change sign, reciprocal, absolute value, square, square root, exponential, and logarithm
  • Scalar (Ave, Power, Max, Min, Resonant Frequency, Q, Notch, Loudness)
  • Windowing (time and frequency)
  • User-defined Equations (e.g. Thiele-Small parameters)
  • Change resolution to Nth octave or user defined linear or logarithmic
  • Nth Octave synthesis
  • Power Summation of any user-defined frequency range
  • Group delay
  • Unwrapped phase
  • Search range to find intersection of two curves (e.g. -3dB points of crossover network)
  • Curve smoothing with 1/3, 1/6, 1/12, and 1/24 octave or user-defined linear or log resolution
  • Loudness rating according to IEEE and ITU-T; example sequences for TIA and other industry standards included
    Attack & Release time calculates the time for the response signal to rise or decay, respectively, by a user-defined amplitude in dB or linear units
  • Directivity Index
  • Resampling and sampling rate correction
  • FFT / Inverse FFT
  • Zwicker loudness (level and spectrum)
  • Standard & arbitrary waveform filtering
  • Active speech level (ITU-T P.56)

Statistics

  • Average
  • Max, Min, Mean
  • Standard Deviation with user-defined sigma
  • Process Control (Cp & Cpk)
  • Best and Worst Fit to Average with ranking
  • Yield
  • Histogram and bell curve fit

Limits

  • Pass/Fail
  • Absolute
  • Floating (x & y directions)
  • Aligned to a pre-defined value (e.g. 0 dB at 1 kHz)
  • Dynamic, using live measurements
  • Waveforms, single values, and curves
  • Control of significant digits
  • Margin, Critical and Failed points

Display

  • Multiple displays on separate tabs allow viewing of curves, single values, and test results with PASS/FAIL indicators; display layout can be transferred to Word or as HTML document; curves with different units (e.g. dBSPL and Ohms) can be displayed in one graph with no limit to number of curves displayed in a single graph; data from any one graph can be exported directly to a new Excel file or pre-defined template
  • Displays include XY graph, table, results, text, polar plots and embedded images
  • Default template and duplicate
  • Save to image file
  • Lock display to protect display layout
  • Data search function

Printing

  • Report generation to Excel, Word, HTML or image files
  • Use of templates (Excel, Word)
  • Print preview
  • Direct print to file or printer
  • Automatic file naming

To see the SoundCheck and NoiseCheck brochure click here