Hello Steve!
So, I did build a complete SL18 oscillator, using my own PCB design and building a switch to address AGC cap switching at the same time as dialing the range.
And... it works. I need to test it with a real Audio analyzer to see how it goes, but at least I can see that it works as intended. Amplitude, frequency etc... and doing a FFT on my crappy SDS 1202X-E gives back good numbers. But... now i need to test the MUX board. How can I go to do that and check the actual performance and operation as intended?
Here's a few pics of the completed project.
Attachments
Hi Pizzigri!
That's beautiful work--- my compliments!
So if I understand correctly, you've implemented the AGC redesign, complete with mechanical switching, and so now have a completed AGC IG-18. You're done, but still want to prove out the IC mux concept for follow-on? Kudos!
I reiterate the desirability of characterizing distortion performance of your newly finished unit; it's the target for performance with the mux addition.
I suggest installing the board with with +/- power supply wiring and range-sensing networks. Confirm expected behavior of the mux address inputs with a 'scope; then you should be able to confirm the intended mux path on each range using a multi-meter's resistance function to confirm conduction on each active mux channel.
To address Mafalda's concern in post #161, check for any deterioration of distortion associated with added bias currents. I'm optimistic for results but his concern deserves investigation.
Then replace mechanical switch connections with the mux path. I advise a single band, single path at a time, first with integrator, then envelope detector detector. Check for THD performance as you go.
Good luck!
Steve
That's beautiful work--- my compliments!
So if I understand correctly, you've implemented the AGC redesign, complete with mechanical switching, and so now have a completed AGC IG-18. You're done, but still want to prove out the IC mux concept for follow-on? Kudos!
I reiterate the desirability of characterizing distortion performance of your newly finished unit; it's the target for performance with the mux addition.
I suggest installing the board with with +/- power supply wiring and range-sensing networks. Confirm expected behavior of the mux address inputs with a 'scope; then you should be able to confirm the intended mux path on each range using a multi-meter's resistance function to confirm conduction on each active mux channel.
To address Mafalda's concern in post #161, check for any deterioration of distortion associated with added bias currents. I'm optimistic for results but his concern deserves investigation.
Then replace mechanical switch connections with the mux path. I advise a single band, single path at a time, first with integrator, then envelope detector detector. Check for THD performance as you go.
Good luck!
Steve