• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 21 subscribers
  • Views 547 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

spur deteriorate of LMX2592

Lilian Chang
Intellectual 1555 points

Hello

I saw a spur of -67dbc @100hz when I was testing  EVM board and my input is 368.64Mhz, output is 2.9412Ghz and Fpd is 184.32Mhz. When I just send the input signal(368.64Mhz) to the Spectrum Analyzer I saw a spur of 81dbc@100Hz. It seems like the spur come from the worse signal source.

I wonder why there is a deteriorative performance of this spur? 

Thanks.

  • 0
    TI__Guru** 107190 points
    Hi Lilian,

    This is because of the scaling between 2941.2MHz and 368.64MHz. There is a factor of 20*log(2941.2/368.64) = 18dB increase in phase noise and spurs. This is not a part specific issue, but a general characteristic of PLL.