Cellular Network Infrastructure » Radio Access Network » OsmoTRX

there is https://github.com/myriadrf/LimeSuite/issues/244 to get more details about the required clock specifications and documentation from lime

looking at the schematic, i think there should be proper termination for 50Ohm, but i see a lot of ringing on the input which i do not see not there when i only connect the gpsdo to a 50ohm terminated scope input.
the screenshots for the input are done with a bnc-t inbetween the gpsdo and the mini, the output ones are directly connected to the mini.

gpsdo slope for reference - without and with 50ohm termination.

i repeated the experiments today with a 'clock converter' based on ltc6957-4 with 40MHz, still usin limesuite 18.10.

sadly i could not get the dcs1800 band to have better results than with the 10MHz square clock from the gpsdo last time.

phase-noise is still way too high for a 'PASS' result (needs to be <5° rms and ~<10° pk) (check phase shots of #3341 and #3342)

next experiment is to use a clock generator based on si5351c

the spec from the clockchip used (ti LMK00105) speaks of "sharp rectangles 2V/ns or better".