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

Nevertheless, gain K can take the value -1. At this point, the transfer function is:
R2
H ( K = −1)
=
R + R
, (IV.23)
1
which leads to a filter gain rise that may be observed on Figure 149. In these condition,
peaking reaches -9.5dB. This rise can be rejected further in frequency increasing the OA gainbandwidth
product, as it may be observed in Figure 150.
Figure 149. Filter peaking gain
Figure 150. Peak frequency versus OA GBW
Z0 and Zf have to be high enough so that the output current of the OA flows through
the RC network of the Rauch filter and not in the non-inverting feedback. Indeed, the
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