Hello,
We are using a DLP in a unique application where we need to maintain high frequency content on our output projected light. Ideally we would need >2 kHz frequency content.
After reading some papers on DMDs I see there is a mode of operation called bit-splitting, where the bit planes of the PWM modulation used for gray scale operation is distributed uniformly across the full frame period, avoiding long periods of off or on time.
Here is an example from a paper I found using a 5-bit DLP ("10.4: Phased Reset Timing for Improved Digital Micromirror DeviceTM (DMDTM) Brightness" by D. Doherty, G. Hewlett):
We are operating with just one color LED, so if could squeeze the bit-split PWM pattern into a 180 Hz frame, we could maximize our mirror switching rate. For an 8-bit gray scale image, I find that we could go as low as 5% (and as high as 95%) on our gray scale level and still maintain >2kHz switching rate (180 Hz * 256/20 = 2.3 kHz).
My issue is that I don't believe we have this level of control over the PWM modulation using the provided C API to ensure this is how it would operate. I'm assuming a lot of this detail is taken care of "under-the-hood". When we project a solid gray scale image over the HDMI and look at the signal with a photodiode, we unfortunately do not see the maximized high-speed switching that I was hoping for.
Can you please let me know if there is any way to control the DLP to this level of detail?
Thank you.
