Virtual Instruments are software versions of a signal generator, multimeter, frequency counter, distortion meter, and a multi-instrument encompassing the multichannel FFT Analyzer, Real Time Analyzer, Oscilloscope and special calculations e.g spatial averaging. They can be used for quick real-time readings, or as building blocks for test sequences. An electronic strip chart recorder can be added to most instruments to display and record levels over time.
Virtual instruments integrate seamlessly with SoundCheck displays, making it easy to compare live and static curves, for example evaluating results against a headphone target curve, or for automotive audio tuning. All virtual instruments can be customized to your specific needs and saved for easy re-use, or set to auto-load on start-up.
Virtual Instruments avoid the need for additional stand-alone laboratory instrumentation, saving money and ensuring that all your instrumentation travels with your laptop.
Manual Signal Generator
The signal generator is used to manually generate any signal. In addition to standard audio stimuli (sine, white noise, pink noise, multitone) with user-selected sampling rates and resolution, it can play any wav file, any memory list file, and any complex waveform created by the stimulus editor. This enables testing with speech or music, and also enables measured responses to be listened to – an important step in correlating measured results to audible defects. The signal level can be referenced to Peak, dB or RMS. The signal can be equalized in real time, and custom EQ curves applied, which is useful when using a non-flat source such as a mouth simulator. A specific portion of a waveform can be selected to play, either by selecting a start and stop time in seconds, or by examining the waveform. Signals may be played for a fixed duration, a fixed number of times, or in a continuous loop. Any available calibrated signal path can be selected, and equalization can be applied from calibration measurements or user defined curves. Multiple signal generators can be opened at the same time and their outputs synchronized, or a delay added for non-coherent playback, for example when generating background noise. Outputs from 2 or more signal generators can also be mixed on the same channel.
Multimeter
Like a conventional multimeter, this virtual instrument indicates the overall level of the input in either linear (V, Pa) or logarithmic units (dB, dBSPL). It can be applied to any available signal path, displaying either RMS or peak voltage or sound levels, accelerometer inputs, and even DC measurements with an appropriate DC coupled interface. In compact view, the meter displays just the output, which is useful if you are measuring many inputs simultaneously. In expanded view, a range of options enables customization of the display. This includes averaging options, time weighting, autoscale controls, standard and user-defined filtering, application of correction curves, and limits. With compatible Listen hardware, gain can be automatically read from the device, and also assigned through the instrument. Average, maximum and minimum values can be saved to the memory list and used in sequences.
Multi-instrument (multichannel RTA, FFT Analyzer and Oscilloscope)
The multi-instrument is a versatile tool featuring an unlimited number of synchronized FFT analyzers, Real Time Analyzers and oscilloscope windows. Each window displays an unlimited number of channels simultaneously and windows can be re-sized and re-positioned for unlimited desktop layout flexibility. A shared trigger between oscilloscope channels as well as the RTA and FFT enables synchronized results display. This is useful for examining measured parameters in both the time and frequency domains, e.g. interchannel time delays and crosstalk. SoundCheck’s multichannel FFT and RTA can even be superimposed on one another for clear comparison of high resolution spectra and constant percentage bandwidth resolution (eg. 1/12th Octave) measurements.
The RTA and FFT Analyzer can perform real-time mathematical operations on live, and a combination of live and static curves, enabling clear display of the difference between live results and a reference curve. Multi-instrument curves are seamlessly integrated with SoundCheck’s standard displays – live curves are displayed in the memory list and can be dragged and dropped into any graph for easy comparison to limits and reference curves. This is useful for quick comparisons to reference standards or golden units, tuning automotive infotainment systems, and more. All multi-instrument functionality can also be used within a test sequence for automation, or to provide a clear read-out of results while the sequence is running.
Multichannel Real Time Analyzer (RTA)The Multichannel Real Time Analyzer uses true recursive digital filtering (ANSI S1.11-2004 Class 0 standard) to analyze signals using constant percentage bandwidth (1/N octave) filters. These measurements correlate well to human hearing and provide the gapless filtering required for continuously analyzing complex signals such as speech, music and pink noise, used in telephony applications ANC headphone measurement. Analysis options include various octave bands up to 1/14, standard and custom weightings, linear and exponential averaging, and time weighting. These can be configured independently for each channel for complete measurement flexibility. The RTA displays any number of channels simultaneously, as well as calculating and displaying channel addition, subtraction, maximum, minimum and power average in real time. This makes it ideal for spatial and sound power measurements.
Multichannel Spectrum AnalyzerThe multi-channel FFT analyzer is a high resolution, constant bandwidth, linear filter analyzer which permits any number of live FFT spectra to be simultaneously viewed in real time on the same graph. It offers many options including standard and custom windows and various weighting options. Averaging times and resolution are continuously variable and can be user-specified. Average, maximum and minimum levels can be identified, and overload and real time indicators highlight any problematic signals. Channel subtraction, maximum, minimum and power average can be calculated and displayed in real time to make efficient use of screen space and allow direct comparisons when making multiple FFT measurements. Typical applications include analyzing broadband speech signals while accurately identifying single frequency interference tones, or analyzing intermodulation distortion in the presence of speech or music.
Multichannel Oscilloscope SoundCheck’s multichannel oscilloscope enables a clear visual view of the waveform over time, and a zoom function makes it easy to closely inspect portions of the signal. Triggering enables the oscilloscope to be used to start a measurement when the input exceeds a certain level, and to save the measurements for later recall or use in a test sequence. Like the multi-intrument’s other tools, the oscilloscope features full multichannel capability, displaying multiple live waveforms on the same graph. A shared trigger between oscilloscope channels as well as the RTA and FFT enables synchronized display of all three results simultaneously. This is useful for examining measured parameters in both the time and frequency domains, e.g. interchannel time delays and crosstalk.
Frequency Counter
A high resolution frequency counter offers an accurate and clear visual indication of frequency, determining the dominant signal in a selected signal path and returning a precise frequency measurement. This measurement can be saved to the memory list and can be used in a sequence, for example for triggering a measurement at a certain frequency. This is useful for calibration (e.g. calibrating audiometers), for testing playback systems to ensure that they are playing back audio at a constant rate, and for any other application requiring a high-precision frequency measurement.
Distortion Analyzer
The real time distortion analyzer offers a quick reading of distortion at a single frequency in real time without having to configure a sequence. Distortion options include THD and THD+N, THD and THD+N residual level, and SINAD. The meter can analyze specific user-selected harmonic, or all harmonics together, and results can be displayed in dB or % relative to the fundamental. Correction curves, and A, B, and C weighting filters along with user-defined arbitrary weighting functions can be applied. Both IEEE and IEC calculation options are available.
Strip Chart Recorder
The strip chart recorder module expands the capabilities of the multimeter, distortion analyzer and frequency counter with the ability to plot measurements over time – the electronic equivalent of connecting a paper chart recorder to a hardware instrument. It plots continuously, or for a predefined amount of time, and can record instantaneous results or repeating averages. This feature is valuable for environmental and reliability testing and in any situation where the behavior of a device over time must be characterized. Results from the strip chart recorder can be saved to the memory list and used inside a sequence just like any other virtual instrument.
Learn more about SoundCheck’s measurement modes:
Virtual Instruments | Test Sequences | Offline Analysis | Open Loop Testing
