Texas Instruments INA1620EVM, User Manual, Page: 10 / 24

Frequency (Hz)
Amplitude (
dBV)
0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000
-160
-140
-120
-100
-80
-60
-40
-20
0
Left Channel
Input Level (Vrms)
THD
+N
Ratio (d
B)
0.01 0.1 1 3
-120
-100
-80
-60
-40
-20
0
Left Channel
Right Channel
Test Setup and Results
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10 SBOU205 – March 2018
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INA1620EVM Audio Amplifier Evaluation Module
Figure 7 shows the THD+N vs Amplitude for a 16- Ω load.
Figure 7. THD+N vs Amplitude for a 16- Ω Load
4.7 Fast Fourier Transforms
For all FFT measurements, a frequency of 1 kHz and amplitude of 1 V
RMS
on the output was used. The 1-
V
RMS
fundamental corresponds to 0 dBV in all FFT measurements. Figure 8 shows an FFT of the left
channel with a 32- Ω load. The second harmonic was measured to be –125.45 dBV.
Figure 8. FFT of Left Channel With a 32-
Ω
Load