Timeline for Bandpass filter frequency response not the same as the one taken from analog filter wizard
Current License: CC BY-SA 4.0
15 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Dec 21, 2022 at 16:13 | answer | added | Audioguru | timeline score: 0 | |
| Dec 17, 2022 at 21:00 | vote | accept | Scipio | ||
| Dec 17, 2022 at 20:16 | answer | added | qrk | timeline score: 1 | |
| Dec 17, 2022 at 19:01 | answer | added | Audioguru | timeline score: 0 | |
| Dec 17, 2022 at 17:17 | comment | added | TimWescott | Given the rated open-loop output impedance of that particular amplifier, it may be profitable to multiply all of your impedances by 10, or even 100 (i.e., increase the resistances by a factor of \$k\$, and decrease the capacitances by the same amount). Doing so may let you bring R4 and R8 to \$V_{ref}\$ without weird things happening -- or at least, with less weird things happening. | |
| Dec 17, 2022 at 17:15 | comment | added | TimWescott | You should not be taking out R4 and R8 entirely -- they're there for a reason. However, since they are AC coupled to the op-amps, you can bring them to ground. The TLV6001 has an open-loop output impedance of \$2300 \Omega\$ and a GBW product of 1MHz -- so at the nominal 5.5kHz loop closure frequency they'll have an inductive reactance of 12 to 13 ohms. With the not-much-higher impedances of R4 and R8, this will cause weird coupling between the stages, and won't quite be ground. | |
| Dec 17, 2022 at 17:12 | comment | added | Scipio | @jonk i dont have the frequency expression, if i had i wouldn't use that filter calculator website. | |
| Dec 17, 2022 at 17:06 | comment | added | Andy aka | What do you mean by: So if i take the load and, what do you mean by: If i take the resistors connect to Vref?? | |
| Dec 17, 2022 at 16:48 | answer | added | Grace | timeline score: 0 | |
| Dec 17, 2022 at 16:31 | comment | added | Scipio | @jonk yes it is and i already tried to do a simulation without it | |
| Dec 17, 2022 at 16:30 | history | edited | Scipio | CC BY-SA 4.0 | added 543 characters in body |
| Dec 17, 2022 at 16:24 | comment | added | Neil_UK | You should not have R9, however I doubt that is the entire problem. I'm suspicious of the 55 and 56.2 ohm resistors, remove them from your simulation and see what happens. TLV6001 should have sufficient GBW for the centre frequency, but it might be marginal on Q. | |
| Dec 17, 2022 at 16:20 | comment | added | jonk | Is that a 50 Ohm load I see there? (Haven't even looked at the TLV6001, yet.) | |
| Dec 17, 2022 at 16:18 | answer | added | Audioguru | timeline score: -1 | |
| Dec 17, 2022 at 16:01 | history | asked | Scipio | CC BY-SA 4.0 |