Audio Precision ATS-1 User Manual

It is most common to limit the bandwidth to 80 kHz, since this will reject high-frequency
noise while passing the second and third harmonics of signals up to 22 kHz, the top of
the audible frequency range.
You may want to limit the lower band limit to remove hum from the measurement.
Using the 400 Hz highpass filter will eliminate the hum products while passing all
fundamentals, interference, distortion products, and noise above 400 Hz.
Following is an example of the use of various bandwidth-limiting filters. The spectrum of
the original signal may look like this:
After the bandpass filter eliminates the 1 kHz fundamental tone, we are left with the
following:
20 50 100 200 500 1k 2k 5k 10k 20k 50k
Hz
-140
+20
-120
-100
-80
-60
-40
-20
+0
d
B
r
A
200k100k 300k
Figure 4-11. Spectrum with no filter
-140
+20
-120
-100
-80
-60
-40
-20
+0
d
B
r
A
20 50 100 200 500 1k 2k 5k 10k 20k 50k
Hz
200k100k 300k
Figure 4-12. Spectrum with fundamental filtered
4 Functions
THD+N (Total Harmonic Distortion plus Noise) Function Descriptions
4-14 ATS-1 Dual Domain User's Manual

Audio Precision ATS-1 Specifications

General

Brand	Audio Precision
Model	ATS-1
Category	Test Equipment
Language	English