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

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

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It is worth highlighting that FOM1 is the highest for the Rauch filter. Compared to the<br />

literature, the <strong>Gm</strong>-C filter <strong>de</strong>signed with the MGTR technique also shows a high FOM1.<br />

Hence, this means that the Rauch filter exhibits the best RF performances versus selectivity<br />

tra<strong>de</strong>-off all over the frequency tuning range.<br />

When taking into account the power consumption, the proposed <strong>Gm</strong>-C filters shows<br />

the best figure. However, process issues when implementing this solution on silicon may<br />

strongly <strong>de</strong>gra<strong>de</strong> the measured results. Reference [VI.1] and the Rauch filter then present<br />

comparable FOM2 results. The Rauch filter is optimized in terms of noise and linearity<br />

whereas the filter in [VI.1] is optimized for low power consumption. Besi<strong>de</strong>s, it has been<br />

chosen a 3.3V supply for the Rauch to enhance the input power of the filter while keeping the<br />

specified performances. With a 1.2V supply, this input power is then reduced.<br />

Future improvements of the <strong>Gm</strong>-C would consist in working on the <strong>Gm</strong>-cell linearity<br />

versus noise tra<strong>de</strong>-off. Perspectives on the Rauch filter mainly concern the improvement of<br />

the operational amplifier <strong>de</strong>sign in or<strong>de</strong>r to increase the bandwidth above 30dB voltage gain.<br />

Conclusion and Perspectives<br />

Two fully active frequency tunable bandpass filters have been simulated, and one of<br />

them measured. The results presented all along this PhD thesis open the perspective of the full<br />

integration of the silicon TV tuner over at least the first two octaves of the VHF band, leading<br />

to the emergence of the first fully-integrated silicon TV tuner.<br />

An encouraging perspective for future <strong>de</strong>velopments is the study of N-path filters<br />

which exhibit a wi<strong>de</strong> tuning range for high RF performances and high selectivity. However,<br />

these topologies may require the modification of the front-end architecture of the tuner to be<br />

used. This may involve important changes on the specifications of each block constituting the<br />

front-end architecture to finally allow reaching targeted tuner NF and harmonic rejection for<br />

instance.<br />

Reference<br />

[VI.1] Y. Sun, C. J. Jeong, I. Y. Lee, J. S. Lee, and S. G. Lee, “A 50-300-MHz low power<br />

and high linear active RF tracking filter for digital TV tuner ICs,” presented at the<br />

Custom Integrated Circuits Conference (CICC), 2010 IEEE, 2010, pp. 1-4.<br />

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