III. Gm-C Filtering - Epublications - Université de Limoges

where
Figure 103. Output noise power computation
Therefore, the total output noise power of this circuit is given by
2 2
2 g m3e
3
V n,
out = , 2
(III.24)
Y
eq
2
e 3 is Gm3 noise power, as it may be seen in Figure 103. Hence, noise strongly
increases as soon as Q increases. On Figure 104 is illustrated the output noise power of the
filter versus frequency for different Q factors. Figure 105 clearly underlines the relation
between output noise power and Q.
f0
Figure 104. Output noise power versus frequency for different filter Q factors
Figure 105. Output noise power versus Q 2
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