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Compressive Sensing system for recording of ECoG signals in-vivo

Compressive Sensing system for recording of ECoG signals in-vivo

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A can be float<strong>in</strong>g when the mix<strong>in</strong>g switch and the Φ 1 -controlled switch are closed. Its value canbe chosen really small by consider<strong>in</strong>g the relation below:(20)Figure 6.2.4.1. Switched-Capacitor Integrator with parasitic effect.By consider<strong>in</strong>g Eq.22, the <strong>in</strong>tegration operation is modified as shown <strong>in</strong> Eq.21:(21)Similarly, the fundamental frequency relation is modified to:(22)By tak<strong>in</strong>g <strong>in</strong>to consideration Eq.20 and Eq.22, C 1 and C 2 can be def<strong>in</strong>ed as is shown <strong>in</strong> Table6.2.4.1.ParameterSampl<strong>in</strong>g frequency (f s )Switch<strong>in</strong>g frequency (f switch )Integration period (Δt)Signal BandwidthC 1C 2CRSpecification33 kHz200 kHz32μs12 kHz1 pF960 fF1 fF5 MΩTable 6.2.4.1. Ma<strong>in</strong> parameters <strong>for</strong> the simulation <strong>of</strong> the SC Integrator-based multipath channel.In practice, the SC <strong>in</strong>vert<strong>in</strong>g amplifier <strong>of</strong> Fig.6.2.4.1 is <strong>in</strong>fluenced by the parasitic capacitors dueto the bottom and top plate <strong>of</strong> the desired capacitor. The bottom plate is shorted out but the topplate parasitic adds directly to the value <strong>of</strong> C 1 . The parasitic <strong>of</strong> C 2 does not affect it, this isbecause one <strong>of</strong> the capacitors (i.e. the bottom plate) is <strong>in</strong> shunt with the amplifier <strong>in</strong>put, which is64

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