Virtins Multi Instrument

VIRTINS Multi-Instrument is a powerful sound card based multi-function virtual instrument software. It consists of the following instruments and functions.

(1) Dual-channel Oscilloscope

It provides four types of views:

• Real time waveform of Channel A and Channel B
• Real time waveform of Channel A + Channel B
• Real time waveform of Channel A - Channel B
• Real time Lissajous Pattern for Channel A and Channel B

Statistical data such as Maximum value, Minimum value, Mean value, Root Mean Square Value are also calculated and displayed. Each frame of data is time stamped with accuracy in minisecond and the time stamp is shown at the lower left corner of the Oscilloscope view.

Digital filters such as Low Pass, High Pass, Band Pass, Band Stop and Arbitrary filters can be applied to the data before any other analyses. The class of the filter can be FFT, FIR or IIR.

The displayed waveform can be played (output) or cyclically played (output).

The Oscilloscope also provides a recording mode which can be used to record data to the hard disk continuously until the recording process is stopped manually or 2 gigabytes of data has been recorded, whichever is earlier.

(2) Dual-channel Spectrum Analyzer

It provides seven types of views:

• Real time Amplitude Spectrum
• Real time Phase Spectrum
• Real time Auto Correlation Function
• Real time Cross Correlation Function
• Real time Coherence Function
• Real time Gain and Phase (Bode Plot)
• Real time Impulse Response

with adjustable FFT size ranging from 128 to 4194304, adjustable window overlap percentage (0%, 25%, 50%, 75%), and 55 selectable window functions such as Rectangle, Triangle, Hanning, Hamming, Blackman, Kaiser and so on. It supports display in logarithmic scale for both X axis and Y axis (dBr, dBV, dBu, dBFS, dBSPL), octave analysis (1/1, 1/3, 1/6, 1/12, 1/24), frequency compensation, frequency weighting (Flat, A weighting, B weighting, C weighting, ITU-R 468 weighting), DC removal, peak hold, averaging, and parameter measurement (THD, THD+N, SINAD, SNR, Noise Level, IMD-SMPTE/DIN, IMD-CCIF1, IMD-CCIF2, Crosstalk, Bandwidth), etc.

(3) Dual-channel Signal Generator (Sweep/Arbitrary/Function/Burst Generator)

It provides the following types of waveforms/tones:

• Sine
• Rectangle (with adjustable duty cycle)
• Triangle
• Saw Tooth
• White Noise
• Pink Noise
• Multi-Tones
• Arbitrary waveform via user-configurable waveform library (WFLibrary)
• Maximum Length Sequence (MLS), with adjustable length (127~16777215)
• Dual Tone Multi-Frequency (DTMF)
• Unit Impulse
• Unit Step
• Musical Scale

at either a fixed frequency, or a frequency that sweeps linearly or logarithmically within a specified frequency range and time duration.

The output signal can be looped back partially (i.e. only one channel while the other channel can be used for field input) or fully (i.e. both channels), via the software itself, to the input of the Oscilloscope for display and analysis in real time. Synchronized operation between the Signal Generator and the Oscilloscope with timing accuracy in the same order of the sampling frequency is supported. Amplitude sweeping and burst signal generation are also supported.

(4) Dual-channel Multimeter

It provides the following types of digital displays:

• RMS
• dBV
• dBu
• dBSPL
• dB(A)
• dB(B)
• dB(C)
• Frequency Counter
• RPM (Revolutions Per Minute)
• Counter
• Duty Cycle
• F/V (Frequency Voltage Conversion)

The latter five involve a pulse counting process, and the software allows you to configure the counter trigger level and trigger hysteresis in order to rectify the analog signal to rectangular pulses before counting. It also allows you to specify the frequency dividing ratio.

(5) Dual-channel Data Logger

It provides long time data logging function for 93 derived variables, including RMS value, Peak Frequency, Sound Pressure Level, RPM, THD, etc. Up to eight data logger windows can be opened and each window can trace up to 8 variables. The logged data files can be reloaded into the data logger for review.

Three logging methods are supported: Fastest (i.e. take one record whenever new data are available), Time Interval (i.e. take one record whenever new data are available and the specified time duration has elapsed since the last update), Update Threshold (i.e. take one record whenever new data are available and the change compared with the last update exceeds the specified update threshold).

(6) Dual channel Spectrum 3D Plot

It is used to trace the spectrum variation with time. Two types of plots are provided:

• Waterfall, with adjustable tilt angle of T axis, adjustable height of Y axis, and selectable color palettes.
• Spectrogram, with selectable color palettes

(7) Device Test Plan

Device Test Plan provides a mechanism for you to configure and conduct your own device test steps. It takes the advantage of the sound card’s capability of simultaneous input & output, to generate a stimulus to the Device Under Test (DUT) and acquire the response from that device at the same time. Different stimuli can be generated and the response can be analyzed in different ways. The DUT can be marked as Pass or Fail after a sequence of test steps. Device Test Plan supports 13 instructions with corresponding parameters. Test results (e.g. Gain vs Frequency, Phase vs Frequency, etc.) can be plotted in up to 8 X-Y plots in real time.

Device Test Plan can also be used to perform other functions such as data file batch processing, batch signal event capturing and storing, etc.

(8) LCR Meter

It is used to measure the value of an inductor, a capacitor or a resistor, or the impedance of a network of them. Two types of external connections are supported:

• Serial connection for high impedance measurement
• Parallel connection for low impedance measurement

The above instruments (1)~(6) are basic instruments and can run simultaneously, while (7) and (8) ride on the top of the basic instruments and require the cooperation of some or all the basic instruments to achieve the specified functions.

A/D and D/A

The sound card is used as the signal input and output device and no additional A/D and D/A hardware is required. The sampling frequency depends on the capability of the sound card. The software allows you to select a sampling frequency of up to 192,000 Hz and a sampling bit resolution of 8 bits, 16 bits or 24 bits, as long as they are supported by the sound card used.

Triggering

For data acquisition, it is possible to specify a trigger condition for collecting a frame of data. A negative or positive trigger delay can be specified so that collecting data can be started before or after the trigger event. The software features a specially designed data acquisition approach which is able to monitor the input signal continuously without missing any trigger event, before a frame of data is collected into the PC memory after the trigger event is found. This makes the software suitable for transient signal recording.

Both level triggering and differential triggering are supported.

Calibration

The software supports the calibration of input and output channels so that absolute values in engineering units can be used for display, analysis or export. It is able to take into account the change of the sound card internal gain setting (e.g. Mic gain, Mic Boost, Line In gain) automatically. It also allows accounting for the external attenuation ratio if an external attenuation circuit is used.

Graph Operation

Zooming and Scrolling is supported in all graphs, enabling you to investigate the fine details of the data. This is very important when a large amount of data are displayed on one screen.

A cursor reader is provided in each graph to show the x and y readings of the actual measurement point. For Spectrum 3D Plot, the cursor reader supports the readout of x, y, t values of the actual measurement point.

Two markers are provided in each graph to get the x and y readings of the actual measurement points nearest (in horizontal direction) to the points of the mouse clicks. The difference in the readings between the two markers are also displayed.

Five chart types are supported: Line, Scatter, Column, Bar, and Step. Line width and colors of the graph are configurable. Options are provided to either display all data points (slow) or only display one data points per vertical raster line (fast).

The data in any graph can be copied into the clipboard as text and later paste into other software such as Microsoft Excel for further analysis. The image of the graph can be copied into the clipboard as Bitmap image and later paste into other software such as Microsoft Word.

Reference Curves

Up to five reference curves can be set for each channel in each graph. The reference curve can be configured by either copying the current curve, or loading a properly formatted text file or a previously saved reference file from the hard disk.

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