Distance2GO continuous modulation (actual FMCW)

Announcements

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
User15867
Level 1
Level 1
5 questions asked First reply posted First question asked
I was unable to modulate BGT transmitter in a true FMCW mode, a continuous triangular/sawtooth wave. I've looked at the output of PLL and it produces a single up chirp, then it turns off and 250 ms later it does another up chirp. I commented out BGT_DUTY_CYCLE in config.h, as Infineon engineer suggested but I'm still getting just a single ramp. How can I modify the code to put device in FMCW mode?
0 Likes
3 Replies
User15583
Level 3
Level 3
First solution authored 10 replies posted 5 replies posted
Which pin did you use to look at the PLL output?
Aren't the 250 ms due to the FRAME_PERIOD_ms (also in config.h)?
0 Likes
User15867
Level 1
Level 1
5 questions asked First reply posted First question asked
radaruser wrote:
Which pin did you use to look at the PLL output?
Aren't the 250 ms due to the FRAME_PERIOD_ms (also in config.h)?


I looked at pins 4, 5 of BGT24MTR11, which is an output of PLL passed through loop filter.
I tried changing FRAME_PERIOD_ms to 50 from 250 and it was set to 50 ms but still this is too slow, I want that to be 0 ms between ramps, or as close to that value as possible. However, the more I learn about BGT IC, the more it appears it's incapable of running FMCW due to heat.
0 Likes
User15583
Level 3
Level 3
First solution authored 10 replies posted 5 replies posted
Well I agree that a frame period of 50 ms is still too high compared to a chirp duration of 1,5 ms (or max 3 ms)...
Maybe anyone else has an idea?

Did you get the information about heat incapability from the BGTs datasheet?
0 Likes