When the spectrum analyzer is running on a 450i radio, is the dynamic RF filter active or inactive?
Not sure about the meaning of the question, but if you're trying to figure if any sort of dynamic RF filter would impair the ability of the spectrum analyzer to show foreign signals, the answer should be 'no'.
AFAIK, 'dynamic filtering' is basically a new buzzword for superheterodyne receivers -correct me if i'm wrong please-. These have better selectivity than direct conversion receivers, so they can isolate better their own channel from adjacent noise. This won't affect their ability to scan a frequency range and take good note of received signals and their powers.
Good lecture (technical warning!): http://www.ti.com/lit/an/swra030/swra030.pdf
@Daniel Gracia wrote:
Not sure about the meaning of the question, but if you're trying to figure if any sort of dynamic RF filter would impair the ability of the spectrum analyzer to show foreign signals, the answer should be 'no'.
AFAIK, 'dynamic filtering' is basically a new buzzword for superheterodyne receivers -correct me if i'm wrong please-. These have better selectivity than direct conversion receivers, so they can isolate better their own channel from adjacent noise. This won't affect their ability to scan a frequency range and take good note of received signals and their powers.
Good lecture (technical warning!): http://www.ti.com/lit/an/swra030/swra030.pdf
Correct, the superhet does not impair the ability or limit the capabilty of the spectrum analyzer. Also PMP 450i's dynamic filtering is more than "just" superhet. There is a lot more work put into it (ex: gain control, Rx sensitivity tweaks etc.) for it to not only block adjacent channel interference but also have improved sensitivity to perform as good as or better than a direct conversion filter.
Thanks,
Sriram
I know that when the radio is operating normally, the filter 'wraps' around the channel to give better isolation from adjacent noise. Does this also happen when the SA is running? i.e. how fast can the filter adapt to the changing Rx frequency such as an SM scanning or the SA running?
@George Skorup wrote:
I know that when the radio is operating normally, the filter 'wraps' around the channel to give better isolation from adjacent noise. Does this also happen when the SA is running? i.e. how fast can the filter adapt to the changing Rx frequency such as an SM scanning or the SA running?
As fast as the changing Rx frequency.