The noise figure of a low phase noise amplifier.

Hi,

I will try to write up an answer to your question (or try to find and post an existing answer that is appropriate) within the next day or two.

Regards,

SMcBride

Hi,

I'm very glad that you can reply me. I haven't gotten an answer yet, can you explan it briefly?

Regards,

Tianyuan Xie

Hi Tianyuan Xie,

Noise figure contributes to the far out Phase Noise(PN) performance, which is PN at higher offset frequencies. Basically Noise Figure degrades the noise floor, noise figure`s contribution to close in PN can somewhat be considered less important, cause generally the close in PN level much higher than the noise floor.

Low phase noise amplifier has good close in phase noise performance, such that they degrade the close in PN of the system minimally, compared to regular amplifiers.

Best,

Kagan

Hi, Kagan,

Thank you for your reply. Can I understand like this, HMC606(Noise figure = 5) has a higher noise floor than HMC564(Noise figure = 1.8), however, HMC606 has better close in phase noise performance than HMC564?

Best,

Tianyuan Xie

Hi Tianyuan Xie,

Yes, your understanding is correct. We do not have phase noise data for HMC564, but I would expect HMC606 to have a better phase noise performance than HMC564, even though the poor NF compared to HMC564.

As a side note, amplifier`s phase noise performance, both close in and far out, can be different under large signal and small signal. The AM noise component of PN can also be different under large and small signal RF drive. PN alone is whole big discussion. Depending on the application requirements, it would be best to test and see.

Best,

Kagan