User Guide Rev. E User Manual

Audio Testing Features
The VTG can output from among six different audio signal formats. The audio level can also
be selected from a range of levels available for each audio format.
Depending on the audio signal format, the audio frequency may be selected from a range of
values (see Front Panel Features on page 2 for button descriptions).
Selecting Audio Signals
The following table summarizes the six audio signal formats available through the VTG.
Pressing the Signal button repeatedly will scroll through the signals and light the green LED
indicators.
Audio Signal
Format
Description
Pink Noise Random noise that has constant energy per octave. Used in loudspeaker
testing and calibration.
White Noise Random noise that has an equal energy distribution across all frequencies
between 20 Hz and 20 kHz.
Sine Wave Used in detecting distortion. The frequency can be set from 20 Hz to
20 kHz (in 1/3 octave steps).
Square Wave Used in amplitude and phase versus frequency measurements. The
frequency can be set from 20 Hz to 5 kHz.
Polarity test Proprietary waveform used in verifying the polarity of audio wiring.
Swept Sine
Wave
Varies the frequency of a sine wave signal continuously from 20 Hz to 20
kHz. Used to detect driver defects and mechanical sources of distortion.
Setting the Audio Level
The audio level for each audio signal type is selected from a range of values using the  or
 Level buttons. The following table lists the range of values.
Audio Signal
Format
Audio Level Range
(in 2 dBu increments)
Audio Level Range
(in 2 dBV increments)
Pink Noise -8 dBu to -56 dBu -10 dBV to -58 dBV
White Noise +6 dBu to -72 dBu +4 dBV to -74 dBV
Sine Wave +6 dBu to -72 dBu +4 dBV to -74 dBV
Square Wave +6 dBu to -72 dBu +4 dBV to -74 dBV
Polarity test -18 dBu to -72 dBu -20 dBV to -74 dBV
Swept Sine Wave +6 dBu to -72 dBu +4 dBV to -74 dBV
NOTE: Displayed levels are for high impedance loads.
For 600-ohm loads, there is a -.7 dB (unbalanced) / -1.3 dB
(balanced) difference between the displayed and actual levels.
VTG 300/300R • Operation 15