Onyx Boox Palma PWM measurement
The smallest Onyx e-reader is the Boox Palma, a phone-sized device with a rather capable processor and a surprisingly bright e-Ink Carta display. It shows no PWM at any brightness level and has an impressively evenly-lit true DC-dimmed frontlight.
Visually measured by camera at 1/6400 shutter speed. Opple Light Master IV used for graph measurements.