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Output Amplitude (V
RMS
)
Tot
al Harmon
ic
Distortion
+
No
ise (
%)
0.0005 0.001
0.01
0.1
1
10
20
20
5E-5
0.0001
0.001
0.01
0.1
1
10
Frequency (Hz)
Gain (dB)
10
100
1000
10000
100000
-120
-110
-100
-90
-80
-70
-60
-50
-40
-30
-20
CMRR
Test Setup and Results
9
SBOU212 – September 2018
Copyright © 2018, Texas Instruments Incorporated
INA1651EVM SoundPlus™ High Common-Mode Rejection Line Receiver
Evaluation Module
4.5
Common-Mode Rejection Ratio
The common-mode rejection ratio measurement was performed by applying a 1-Vrms common-mode
signal to the input and measuring the gain of the signal at the output. The frequency of the input signal
was swept from 20 Hz to 90 kHz, and the measurement bandwidth of the
Audio Precision APx555
was set
to 90 kHz.
shows a measurement of the CMRR.
Figure 6. Common-Mode Rejection Ratio (CMRR) Measurement
±15-V Supplies, 1-V
RMS
Input, 90-kHz MBW
4.6
THD+N vs. Amplitude
The
THD+N vs. Amplitude
measurement was performed by sweeping the output signal amplitude from
1 mV
RMS
to 13 V
RMS
at a frequency of 1 kHz. The measurement bandwidth of the
Audio Precision APx555
was set to 22 kHz.
shows a measurement of the
THD+N vs. Amplitude
.
Figure 7. THD+N vs. Amplitude Measurement
±15-V Supplies, 1-kHz Output, 22-kHz MBW