Excellent work - very well built! Not sure about the HP 334A but the HP 333A has an output from the filter that can be connected to your spectrum analyzer to extend the dynamic range. You might keep an eye out for an HP 3562A Dymanic Signal Analyzer - if you really want to go further down that rabbit hole. Regards, David
I’m a big fan of the ESP website. I’ve spent quite a bit of time reading the articles there. Thanks for the info on the the other topologies, I will have to look into them some more. This twin tee only goes to 20Khz but I’d really like to extend that range to 200khz. I think that is possible using a SVF, not sure about twin tee though.
I’d say the switches are probably the most expensive. Depends on what you can find or have lying around. I sourced them from eBay so it’s really variable on cost. Components are from Mouser or what I had on hand. I think maybe total cost for me was around 50-75 USD.
Serious question here because I think I don't totally understand. Why do you need the notch filter if you can just see the harmonics on your scope and ignore the fundamental?
Removing the fundamental allows me to look at the smaller level harmonics without overloading the front end of the spectrum analyzer. The “down ranging”. On the lower ranges (the more sensitive input levels) the high power of the fundamental will overload the front end of the analyzer. Best case it will cause distortion in the analyzer and a false reading. Worst case it can damage the front end. Also, when you’re taking a harmonic distortion reading you’re measuring the power levels of the harmonics, you don’t include the power of the fundamental. When I use the RMS meter to sum the harmonic levels, I don’t want to add the power of the fundamental. Great question and thanks for the comment.
For signals with high harmonic content you could ignore the fundamental if you’re using a spectrum analyzer. If you’re looking at lower harmonic content, say below about 60 db, you really need to remove the fundamental as most spectrum analyzers will not have the dynamic range needed for very accurate readings. My 3585B tops out at around 70-80db before I have to null the fundamental. Big thing though is over driving the front end.
Nice internal construction. I like the logical layout and separation……resulting in its good functionality.
Excellent work - very well built! Not sure about the HP 334A but the HP 333A has an output from the filter that can be connected to your spectrum analyzer to extend the dynamic range. You might keep an eye out for an HP 3562A Dymanic Signal Analyzer - if you really want to go further down that rabbit hole. Regards, David
I’m a big fan of the ESP website. I’ve spent quite a bit of time reading the articles there. Thanks for the info on the the other topologies, I will have to look into them some more. This twin tee only goes to 20Khz but I’d really like to extend that range to 200khz. I think that is possible using a SVF, not sure about twin tee though.
What would you estimate the availability of parts and the total your cost not counting time? Very nice video! Had to sub.
I’d say the switches are probably the most expensive. Depends on what you can find or have lying around. I sourced them from eBay so it’s really variable on cost. Components are from Mouser or what I had on hand. I think maybe total cost for me was around 50-75 USD.
@@FreeElectron Thanks! That's not bad.
Serious question here because I think I don't totally understand. Why do you need the notch filter if you can just see the harmonics on your scope and ignore the fundamental?
Removing the fundamental allows me to look at the smaller level harmonics without overloading the front end of the spectrum analyzer. The “down ranging”. On the lower ranges (the more sensitive input levels) the high power of the fundamental will overload the front end of the analyzer. Best case it will cause distortion in the analyzer and a false reading. Worst case it can damage the front end. Also, when you’re taking a harmonic distortion reading you’re measuring the power levels of the harmonics, you don’t include the power of the fundamental. When I use the RMS meter to sum the harmonic levels, I don’t want to add the power of the fundamental. Great question and thanks for the comment.
For signals with high harmonic content you could ignore the fundamental if you’re using a spectrum analyzer. If you’re looking at lower harmonic content, say below about 60 db, you really need to remove the fundamental as most spectrum analyzers will not have the dynamic range needed for very accurate readings. My 3585B tops out at around 70-80db before I have to null the fundamental. Big thing though is over driving the front end.
@@FreeElectron Thanks for the reply! I understand, and I can now see how you are showing that in your video.