Metric Halo SpectraFoo - Manual (Page 54)

Instruments
54
Figure 3.71: Parameter control button
The Frequency Locked indicator will come on when the THD Meter senses a single frequency signal, and will
display the frequency.
• The S/(N+D): display shows the signal to noise plus distortion measurement.
• The THD+N display shows the total harmonic distortion plus noise measurement.
Both measurement are shown as a percentage, as well as their levels in relative (dBr) and full scale (dBFS) units.
The THD Meter also shows the input level referenced to full scale. By clicking the "A-Weight" checkbox, the
results may be weighted.
To properly use the THD meter, use must analyze a single frequency signal. An easy way to do this is by using
SpectraFoo's
Signal Generator , with synchronization enabled.