(HELP PLZ!)What is this signal (video from O'scope)?

[jstpie5]

As the subject implies I need help identifying the waveform on the video link below (and possibly recreating it later).

The signal is the feed to a John Deere hydraulic solenoid. The signal and return wires were connected to a load resistor with the same value as the solenoid for testing purposes (5.5 ohms).

I was expecting it to be PWM and it looks more like a rectified sine wave that increases in voltage and decreases in frequency as the joystick is pulled further back (more power).

I am trying to take control of the hydraulic solenoid with an Arduino and MOSFET (or similiar) and I would like to use a similar signal as what John Deere uses. PWM works ok to control the solenoid but I am now curious what John Deere is doing and why.

Any help is appreciated!

Video starts with solenoid getting full power. Then the power is varied by moving the joystick back and forth.

Low power signal frequency is ~22kHz
Low power voltage is from 0 to ~10V
High power signal frequency is ~20kHz.
High power voltage is from ~2.5-10V

-James

[Simon]

Topic locked. Please do not double post the same topic, it causes confusion and annoys other members.