Timeline for Need help improving the Caller ID FSK demodulation circuit
Current License: CC BY-SA 4.0
11 events
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| Mar 3, 2020 at 1:33 | comment | added | zysoft | I need both frequencies in the same line. The signal comes in as an FSK modulated signal at 1200 baud where logical mark ("1") is 1200 Hz, and logical space ("0") is 2200 Hz, so I need to only pass two frequencies and attenuate everything else. The input seems to go to the demodulator's internal amplifier which is configured as differential, and R1 and R4 define its gain along with some others. | |
| Mar 3, 2020 at 0:21 | comment | added | MadHatter | Do you need both frequencies on both lines? I figured 1 frequency per line? If so, maybe this is not the best approach. Otherwise, you could put the 2 in parallel, but that's a lot of components for what your doing. | |
| Mar 2, 2020 at 22:32 | comment | added | zysoft | Thank you for your help! The last thing I can't figure out is how to combine two of these filters into a single dual-band one, since I need both frequencies to be able to pass. I would appreciate any advice! | |
| Mar 2, 2020 at 22:32 | history | bounty ended | zysoft | ||
| Mar 1, 2020 at 17:41 | history | edited | MadHatter | CC BY-SA 4.0 |
added 95 characters in body
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| Mar 1, 2020 at 17:31 | history | edited | MadHatter | CC BY-SA 4.0 |
More details.
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| Feb 28, 2020 at 5:09 | comment | added | zysoft | Found some, thanks! | |
| Feb 28, 2020 at 5:04 | history | edited | MadHatter | CC BY-SA 4.0 |
added 200 characters in body; added 215 characters in body
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| Feb 28, 2020 at 5:03 | comment | added | MadHatter | Google LC resonant filter. f=1/2πSqrt(LC) | |
| Feb 28, 2020 at 2:40 | comment | added | zysoft | Thank you! I've simulated it in LTSpice and it seems to provide great frequency response! I will build it and try on the real line. Could you point me to the math behind it please? | |
| Feb 28, 2020 at 1:59 | history | answered | MadHatter | CC BY-SA 4.0 |