SDR Transceiver - Part 3 Audio and TR Switch

In this video I continue the SDR Transceiver series moving on to the Transmit/Receive and Audio switches
Previous videos in the series
Part 1 - • SDR Transceiver - Part...
Part 2 - • SDR Transceiver - Part...
Here is the SDR Transceiver kicad
github.com/thaaraak/SDR-Trans...
Here is the code I was using:
github.com/thaaraak/SDR-Trans...
github.com/thaaraak/SDR-Trans...
0:00 Intro
1:07 Note on problems encountered with ESP32-A1S
2:33 Recap on ESP32-A1S GPIO config
3:45 Audio Out - where I will be probing on the circuit
4:19 Audio Output from the board
5:27 Testing Audio In (and comparing to a professionally made board)
8:09 Installing the FST3257 Audio Switch and PTT switch
10:08 Testing T/R voltages
11:05 Testing Audio Switch Output
14:07 Testing Audio Switch Input - approach
15:46 Testing Audio Switch - setup
16:17 Audio Switch for RX
17:29 Audio Switch for TX
19:40 Wrap up and Next Steps

[@M0XFXUK]

Really interesting work you are doing here. I love the Tayloe mixer to produce the in phase and quadrature components and vice versa. I would never of thought that a multiplexer would work so well as a quadrature mixer. The SI5351 is also impressive as the sine and cos LO. Got the bug now need to start playing with this stuff. Thank you for such great content. 73 M0XFX 👍👍👍

[@na5y]

Thanks again John - glad you enjoyed

[@chrisherd991]

Excellent video, I learned a lot. Really appreciate the use of test instruments in conjunction with the block diagram and the circuit diagrams.

[@na5y]

Thank you Chris - glad you enjoyed

[@TheJavaSync]

True!! nice & slow English explanation Loved it so much ❤

[@antaf56]

Great presentation Ian, very informative and helpful. Can't wait to watch the next episode! Thanks for all! Antonio

[@na5y]

Thank you Antonio!

[@MrNoorino]

great work, you explain very well

[@na5y]

Thank you Noor!

[@juststeve7665]

great video! I enjoy how meticulous you are with your builds. LOL You must be downstairs... in the basement? In several videos footsteps can be heard...

[@na5y]

In the garage which is underneath the living area... I am surprised you didn't hear my dogs howling. They were locked up at that time ;)

[@VU3ZNL]

I like your homebrewing sir beacuse you give us schematic which helps us a lot and sir is this ready now

[@na5y]

Glad you enjoyed - I don't know myself that'll it'll work perfectly though yet. I've already found a few bugs

[@VU3ZNL]

@@na5y ok sir thank you

[@TheEmbeddedHobbyist]

Can't remember if you're running dual rails for audio supply or single. But either way you need to think about dc levels 8n the switched audio, if the dc levels eg 0V or 1/2 rail. As any difference in dc levels either side of the switch will cause audio pops as the caps charge or discharge. Just a thought

[@na5y]

Just single rail for this one - and we'll have to see how my mid-rail bias setup goes! Thanks for the comment TEH!

[@DAVIDGREGORYKERR]

Just be advised that a white wire has come adrift or is not connected.

[@ElectronicSupersonic]

I think my software counterpart contacted you about the A1S recently, we based our design on the ai thinker audio kit and the modules we got from Aliexpress were a different rev, the I2C pins were on 23 and 18 if I recall and I think I2S SCLK was GPIO5, the problem is we were using these IO's for buttons and indicators and we can't seem to get the newer A1S unless we do a 2k order from AI thinker, it killed a board rev. But oh well moving on, we are going with a standard ESP32 and discrete 8388 on the next version. I can send you one of our modules if you'd like.

[@na5y]

Thanks for the info Jesse. Its a shame the ESP32-A1S has such variability and incorrect documentation. I am thinking of doing the same as you after this: ESP32 + discrete ES8388. Are you using a specific ES8388 board or just creating your own combo?

[@ElectronicSupersonic]

@@na5y we are going to start with the PCB artist board for a revision I think then go discrete the next revision as we move to a more production ready unit

[@ElectronicSupersonic]

I'd like to move to a different codec because it's not available in the US but there's a wealth of code already for the 8388. Sparkfun just released a dev board for a cool codec and example code but it's an obsolete chip :-/

[@na5y]

@@ElectronicSupersonic I do like that little PCB artist board. All the best with your product!

[@na5y]

@@ElectronicSupersonic I might try playing around with the PCM3060 codec in a future video. I have seen it used before successfully with SDRs

[@DAVIDGREGORYKERR]

I wonder why a SDR transceiver can not be built around the UDOO RYZEN Bolt V8 Maker Board SBC and using a I/O Hat for the ARDUINO.

[@na5y]

I haven't played around with that board - but so long as you have GPIO access and I2S is supported I am sure you could