https://www.marcelpost.com/wiki/index.php?title=Opamp-filters&feed=atom&action=historyOpamp-filters - Revision history2024-03-29T15:57:06ZRevision history for this page on the wikiMediaWiki 1.39.5https://www.marcelpost.com/wiki/index.php?title=Opamp-filters&diff=1673&oldid=prevAdmin at 03:05, 2 November 20142014-11-02T03:05:28Z<p></p>
<p><b>New page</b></p><div>Single-Supply (no negative voltage required) first-order (single-pole, 6dB/Octave, 20dB/Decade) audio filters.<br />
<br />
These filters are optimised to provide 6dB/Octave for the 1200Hz and 2200Hz tones required for Packet or APRS transmissions over FM.<br />
<br />
* Prototype #1<br />
<br />
[[File:LPF-HPF prototype1.jpg|200px|thumb|none|veroboard with HPF (left) and LPF (right)]]<br />
<br />
[[File:LPF-HPF prototype1 box.jpg|200px|thumb|none|circuit board inside enclosure]]<br />
<br />
<br />
2014-11-02 -- completed a first prototype housing both the LPF and HPF and ready for testing with the TNC-Pi and IC-207H. A dual-opamp package is used (NE5532) and since both designs work off a single-supply all grounds can be nicely connected together. Further testing will reveal if this design is up for the task.<br />
<br />
<br />
<br />
==Low-Pass Filter (De-Emphasis)==<br />
<br />
[[File:Low-pass-ss.png|200px|thumb|none|LTspice trace and schematic of the filter in action]]<br />
<br />
LTspice LPF Model: [[File:Opamp-NE5532 lowpass-de-emp single.zip]]<br />
<br />
Ltspice NE5532 dual op-amp library: [[File:NE5532.zip]]<br />
<br />
<br />
<br />
<br />
==High-Pass Filter (Pre-Emphasis)==<br />
<br />
[[File:NE5532 HPF.jpg|200px|thumb|none|veroboard prototype of the High-Pass filter]]<br />
<br />
[[File:High-pass-ss.png|200px|thumb|none|LTspice trace and schematic of the filter in action]]<br />
<br />
LTspice HPF Model: [[File:Opamp-NE5532 highpass-pre-emp single.zip]]<br />
<br />
LTspice NE5532 dual op-amp library: [[File:NE5532.zip]]</div>Admin