lhlbluesky_lhl
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i have uploaded the BPF fig, TFS and GFS. but i have some questions in transient simulation. 1, for TFS, the AC response shows that, f0=20.4KHz(ideal 20KHz), Q=9.23(ideal 10), H0=0.5(ideal 1). when transient simulation(an AC coupling cap added before VIN), the virtual ground is 0.8V(positive input of g1 and negative input of g2), and i add a 20KHz sine wave(0 to 0.2V pk-pk), but vout is only 0.5V or so (and very slowly increasing). why? any mistakes here? C1=10pF, C2=1nF, gm1=gm2=gm3=13uS. 2, for GFS, the AC response shows that, f0=20.5KHz(ideal 20KHz), Q=9.28(ideal 10), H0=0.4(ideal 1). when transient simulation(an AC coupling cap added before VIN), the virtual ground is 0.8V also, and i add a 20KHz sine wave(0 to 0.2V pk-pk), but vout is only 0.2mV pk-pk sine wave(dc offset=0.78V, not 0.8V). and why H0 becomes so small (1/1000)? any mistakes here? C1=10pF, C2=1nF, gm1=gm2=gm3=13uS. thanks.
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