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

Here is the SDR Transceiver kicad

Here is the code I was using:

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

[chrisherd]

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

[antaf]

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

[MXFXUK]

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 👍👍👍

[justme-n-gracie]

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...

[VUZNL]

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

[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

[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.

[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.