ESP32 Based SDR Transmitter - Part 2 Tayloe Encoder

In this video I continue the transmitter series and move on to the Tayloe Encoder which mixes the I and Q audio signals together with the LO to produce a sideband signal (either upper or lower)

Previous video:

The code:

Schematic:

0:00 Intro
0:54 Schematic walkthrough
2:20 I/Q to 0/90/180/270 opamps installed
03:25 0/90/180/270 audio signals tested
04:49 A diversion into some interesting patterns produced with quadrature audio signals
06:50 Tayloe Encoder installed
09:13 Looking at the code to swap upper and lower sideband output
10:15 Testing the output signal on the oscilloscope
13:36 Looking at a single tone SSB signal on the spectrum analyzer
15:31 looking at the effect of adjusting the I/Q balance
17:15 Looking at a two tone SSB signal
18:22 Looking at the out of band harmonics and wrap up

[rfdave]

It's ok if you run long videos I don't mind. Very interesting, so enjoyed it. Can't wait for the next episode ...

[yakovdavidovich]

Nice, I built a similar IQ modulator with FSAU3157s not too long ago; had very similar results. I noticed at 4:30 that the blue trace is substantially higher amplitude than its counterpart 180-degrees away. In addition to the one trimmer for IQ balance, you might want to add a trimmer in the feedback path for one opamp in each channel so you can adjust balance there too.

[RAUK]

A very nice video, as always. Many thanks for sharing!

[alteriaautomation]

May I ask what version of the ESP32 SIP are you using. It looks you are using the new ESP32 with I2S. Is that still a dual core? Could you dsisclose the part number? Thanks in advance

[jeroldponko]

Very nice demonstration of Lissajous patterns on your oscilloscope. Not only pretty but useful in determining things like zero beat. Keep up the good work!

[ploegmma]

Thank you, as always good valuable content