UWB Receiver Dyanamic Range

[samchieh]

Hi All,

I've done a lot of literature search, but wasn't able to understand how the Dynamic Range of a UWB receiver should be analyzed or perceived. Since the bandwidth of the signal is so large, that means the noise floor will be higher, leading to a degraded Dyanamic Range.

Say B=5GHz NF=9dB

F=-174dBm+9dB+10logB = -68dB which is bad

Say B=100kHz

F= -115dB which is good

What am I missing? Does anyone know or have a good paper to reference?

Thanks!

 

[RFCMOS]

Hi,

I do not know about UWB standard however the dynamic may be determined by the reference sensitivity (noise figure) from one side and by the maximun signal you can have at the input of the receiver with some margins taken for the envelope variation.
Hope this helps.

Regards.

 

[samchieh]

Yup...I can understand the definition of Dynamic Range for most narrowband systems, but for the UWB system, the bandwidth is so large that the sensitivity is vastly degraded.

Sensitivity is defined by: Psenstivity=Psig+NF+SNRmin+10logB

now if B is 5 GHz, then the sensitivity is terrible.

Perhaps I'm looking at the sensitivity wrong for UWB and maybe the definition of Sensitivity for impulse radio is different than that of classical narrowband systems.

Any Ideas?

Thanks!

 

[vfone]

https://www.ee.ucla.edu/~brweb/papers/Conferences/R&AetcCICC05.pdf

 

[samchieh]

I seen this paper before, and I think what they do is chop up the large bandwidth into smaller channels, so they design a channelized front end. But this is narrowband in nature I believe....just a whole bunch of narrowband channels. That is why the sensitivity and dynamic range can be so good.

Is there another way to do this other than to use a channelized reciever? What happens when I build a front end capable of receiving a 5GHz bandwidth? 10GHz?
See...now using the same equations for senstivity and dynamic range, the values are much worse, maybe even laughable.

So..that's the question........


Thanks for the responses though, they are helpful in this discussion.

 

[jallem]

I think you should include the
process gain.

 

[samchieh]

I think you are right....but can we think of the UWB pulse as being spread spectrum?

 

[jallem]

I would think that mathematically
speaking UWB and spread spectrum
are the same. The effect are the same,
UWB use a short duration pulse and
spread spectrum(at least DSS) use
pseudo random that when is represented
in time domain becomes the same.

https://www.informit.com/content/images/chap1_0131463268/elementLinks/01fig12.gif

 

[samchieh]

thanks a lot! that article really helped.