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

III.3.b.ii Simulated Filter Performances
This filter covers the range 45 – 385MHz. It provides a mean Q factor of 3.5 for a gain
between 10 and 12dB as it may be seen in Figure 127.
Figure 127. Filter Gain and Q-factor for various central frequencies
In-band linearity is depicted in Figure 128. IIP3 lies between 2 and -4dBm for a 18dB
noise figure.
Figure 128. Filter RF performances versus central frequency
This latter graph demonstrates that the linearity of the transconductors is not high
enough to ensure a high linearity for the filter. Besides, Figure 205 underlines a certain
sensitivity to process and mismatch variations. Hence, this has to be compared with the
second linearization technique.
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