Oscilloscope (dual channel, xy, time
division, trigger);

Spectrum Analyzer with amplitude and phase
display (linear, log, lines, bar, octaves band analysis 1/3, 1/6, 1/9, 1/12,
1/24);

Wave-form generator with "custom functions", triangular,
square, sinus, white noise and pulse generation (NO ALIASING);

Frequency meter (in time and frequency
domain) and counter; in time domain by means of a real time zero crossing
algorithm;

Volt meter with DC, true RMS, peak to peak and
mean display;

Filtering (low pass, hi pass, band pass, band
reject, notch, "diode", DC removal);

Memo windows (data log) for analysis and storage of
time series, spectrum and phase with "triggering" events;
possibility to save in various formats and display them with a viewer;

A TRUE software digital analog conversion
(for complete signal reconstruction using Nyquist theorem) ;

Frequency compensation: one can create/edit a
custom frequency response and add it to the spectrum analyzer spectrum ;
added standard weighting curves A,B,C in parallel with custom frequency
response;

Support for 8/16/24 bit soundcard by means of
API calls;

Unlimited frequency sampling (depend from the
capabilities of your soundcard);

Cepstrum analysis;

Cross Correlation;

Extended THD measurements, with automatic
sweep and compensation.

ZRLC-meter with Vector scope, automatic sweep
in time and frequency for automatic measurement.

VA main form (version 8.x.x)

(1) - Oscilloscope

Dual channel

Bandwith : depends from your soundcard (typical
20 Khz) up to 96 Khz (192 Khz sampling frequency)

Resolution from 8 bit (S/N 46 dB) up to 24
bit (S/N >120 dB)

Time division adjust according the sampling
frequency and sample resolution

Trigger (positive/negative slope) independent
for both channels

Complete software D/A of digital samples :
the Nyquist theorem allows reconstructing exactly the input signal

Utilities for quick frequency determination (hold
left mouse button down and move mouse to get frequency/amplitude)

Y-axis in Volt and percent full scale

Auto calibration of scope (and spectrum) in
volts (need an input signal of known amplitude)

(2) - Spectrum Analyzer

Dual channel

Bandwidth : same as point (1) (oscilloscope
function): is the half
of the sampling frequency. Typical for 44100 Hz is 22050 Hz (up to 96 Khz or
ore depending of the acquisition board)

Resolution from 8 bit (S/N 46 dB) up to 24
bit (S/N >120 dB)

X-axis in Hz, logarithmic and linear; zoom
x1..x16

Y-axis in dB or Volt (calibration needed);
linear/logarithmic; zoom

Average on spectrum up to 200 buffer

Direct window for amplitude with mouse

Auto-scale

Capacity to modify the zero dB level
(manually/automatically)

Octave band analysis (1/1, 1/3, 1/6, 1/9, 1/12, 1/24)

(3) - Wave-form generator

Dual channel

Independent sampling frequency/resolution from
scope/spectrum (up to 192 Khz/24 bit)

Phase between channels (degree)

Direct real time generation/ loop with
predefined buffer

Waveform CUSTOM, built with harmonics (with
save/load in file ".fun" of defined waveform)

Modulation of custom waveform with
sinus/square/triangular

Real time parameters variation (amplitude,
frequency, phase between channels, type of waveform)

(4) - Frequency meter

Dual channel

Frequency meter in Hz/Time/Counter of the
input signal being visualized in spectrum/scope

Read the frequency of the harmonic of maximum
amplitude

Counter with threshold level

(5) - Volt meter (calibration needed)

Dual channel

Vpp, True Rms

Hold function

(6) - Filtering

FIR low pass cut-off frequency user defined

FIR high pass cut-off frequency user defined

FIR band pass cut-off frequencies user
defined

FIR band reject cut-off frequencies user
defined

IIR notch cut-off frequency user defined

IIR notch-inverted cut-off frequency user
defined

"Diode" function

DC removal

Dual filter (one for each channel)

(7) - Memo windows

Aquiring of spectrum with average

Edit offline (while VA running) of aquired
spectrum: zoom, navigate

Saving of spectrum in TXT format

Clipboard for aquired spectrum

Print of aquired spectrum

Mark points for each valid point (harmonic)
of spectrum

Aquiring of scope points (points aquired in
time domain)

Edit offline (while VA running) of aquired
time series: zoom, navigate

Saving of samples in TXT format

Clipboard for aquired samples

Print of aquired samples

D/A conversion: the points aquired may be
converted using Nyquist theorem for full reconstruction of signal in
time domain (see point 8 for D/A in real time)

(8) - real time DIGITAL/ANALOG conversion

D/A in real time

Dual channel

Allows visualizing each aquired harmonic

Points (8) need a clairification:

VA has the unbeatable feature to perform a full real time
Digital-Analog conversion for the oscilloscope function.

Consider using a frequency sampling of (standard)
44100 Hz, with a 16 bit resolution (resolution is not relevant for the purpose
of the discussion below...)

Other programs similar to VA simply plot the raw points on the screen, which
means you can’t easily analyze signals with a frequency higher than 3000/5000 Hz
(there are limited points to plot). Even worse, think a sinusoidal signal of 20
KHz. You would have only 2 points (more or less) per cycle! ... The Nyquist
theorem says that it is sufficient to RECONSTRUCT the original signal...try to see what
happens if you draw a sine with only two points ...it will appear like a
triangular waveform...

Try the power of VA enabling the function "full D/A", apply a sinusoidal signal
of 15-20 KHz (for example using the Waveform generator included in VA) finally
use the "Time division" control for the selected channel (mS/d) to display the
signal at the desired detail level. You will see a perfect waveform with all the
points of the original signal (not only two).

(9) Frequency compensation

Visual Analyser allows you to apply a predefined
frequency response to compensate (for instance) the frequency response of
a microphone. You should know the frequency response of your microphone;
normally professional microphone should be shipped with the typical frequency
response. You can add a limited number of points in VA, and apply. VA will
interpolate a continues curve by means of cubic spline interpolation
algorithm. You can do it through the windows below.

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Last modified: 03/25/14