SSM2142
THD PERFORMANCE
The following data, taken from the THD test circuit on an
Audio Precision System One using the internal 80 kHz noise
filter, demonstrates the typical performance of a balanced pair
system based on the SSM2142/SSM2141 chip set. Both dif-
ferential and single-ended modes of operation are shown, under
a number of output load conditions which simulate various
application situations. Note also that there is no adverse effect
on system performance when using the optional series feedback
capacitors, which reject dc cable offsets in order to maintain
optimal ac noise rejection. The large signal transient response of
the system to a 100 kHz square wave input is also shown,
demonstrating the stability of the SSM2142 under load.
+18V
10µF*
4
6
7
2
8
1
A
C
V
IN
SSM
3 2142
5
R
L
B
SSM
2141
V
OUT
Figure 9. THD+N vs. Frequency at Point B
(Differential Mode)
10µF*
R1
R2
–18V
*USED ONLY IN THD PLOTS AS NOTED.
ALL CABLE MEASUREMENTS USE BELDEN 8451 CABLE.
Figure 7. THD Test Circuit
Figure 10. THD+N vs. Frequency at Point A
(Single Ended)
Figure 8. THD+N vs. Frequency at Point B
(Differential Mode)
Figure 11. THD+N vs. Frequency at Point C
(SSM2141 Output)
–4–
REV. B
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