Digilyzer DL1 User Manual
Digilyzer DL1 User Manual
Digilyzer DL1 User Manual
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THd+N<br />
The THD+N function (Total Harmonic Distortion+Noise) calculates<br />
the deviation of the input signal from an ideal sine wave. This<br />
measurement is most important to check and qualify analog/digital<br />
converters.<br />
Full scale<br />
indication<br />
Filter<br />
Measurement Functions<br />
Fundamental<br />
frequency<br />
Fig 5-50, THD + N screen<br />
The <strong>Digilyzer</strong> is able to calculate THD+N values down to –100dB<br />
(0.001%). For better THD+N values “< -100 dB“ (< 0.001%) are<br />
displayed.<br />
THd+N results of the selected channel may be displayed in dB or %.<br />
Full scale indication appears whenever one sample reaches full<br />
scale. This indication is independent of the clipping of the PPM<br />
meter.<br />
Filter: The audio signal decoded from the digital audio stream can<br />
be filtered with the following filters prior to the RMS or THD+N<br />
calculations:<br />
• HP400, highpass 400 has a good rejection in the area of main<br />
frequencies – so hum problems may easily be examined and<br />
localized. The HP400 is also used to measure quantization<br />
noise.<br />
• 22-22k, bandpass 22-22k is used to define the commonly used<br />
measurement bandwidth from 22Hz to 22kHz.<br />
47<br />
Level RMS<br />
THD+N<br />
result<br />
Display mode