I assume the display is showing us the pulse width in µS?
Which for standard servos should vary between 1000 and 2000. 1500 being neutral/rest.
I'm further assuming that the slider display on the left should show the analogue of the control stick/servo tester pot position.
So we should actually see that move up and down when the control input is moved.
But I can't see any correlation there!
As an ex test/development engineer I have to ask😔
Can you post a pic or diagram of the test setup please? By what is the PWM read?
I'm also wondering if the capture, conversion, WiFi circuits are introducing their own delay/jitter/distortion. Early on in my career I learned the test engineers mantra; keep the test setup as simple as possible, commensurate with the parameters to be measured, and enclosed. WiFi is NOT enclosed and is subject to it's own interference sources.
Unless you are living as a hermit in a cave due to Corona🤔
But if it is only transmitting the captured values as bits it probably has little or no influence here. It's the capture and conversion accuracy which is important.
Jitter has always been a major problem in telecommunications, esp. since digital exchanges, line amplifiers and Internet nodes, relays etc.
Many of my colleagues back then made a good living from the purveying of expensive Jitter measurement systems.
As previously written; I'll do some tests the 'traditional' way.
Using a fast scope with high impedance inputs that have the least possible influence on the results.
I hope that my dual trace scope is good enough, and fast enough, to show me simultaneously the difference between what is generated in the TX / Servo Tester and what is actually fed to the servo from the RX.
If it works it could be quite enlightening. I can scarcely hope to compete with the manufacturers though🤔 But I'll do my best.
Off to the 'bench' to sweep away my micro RC gear tests to investigate this phenomenon.
I have a vested interest as I have a large (and expensive) Akula 2 sub kit also using 40MHz RF.
So I will also test the included RX and dive plane servos and depth control systems most exhaustively! I also have a dynamic diving 1/72 type 1A U-Boot that I was hoping to convert to static diving. If I remember correctly this whole investigation started with an enquiry related to a submarine project.
C U in a week or month or so ....
(Please send a search party, with Red Cross recuperative water and food pack if nothing heard after four weeks😉)
Cheers, Doug 😎