Copyright: 1996 - 2024
BSEE - KB3UON
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UWB PA transmitted power and spectrum mask? - RF Cafe Forums
RF Cafe Forums closed its virtual doors in 2012 mainly due to other social media
platforms dominating public commenting venues. RF Cafe Forums began sometime around
August of 2003 and was quite well-attended for many years. By 2010, Facebook and
Twitter were overwhelmingly dominating online personal interaction, and RF Cafe
Forums activity dropped off precipitously. If the folks at
phpBB would release a version with integrated
sign-in from the major social media platforms, I would resurrect the RF Cafe Forums,
but until then it is probably not worth the effort. Regardless, there are still
lots of great posts in the archive that ware worth looking at.
Below are the old forum threads, including responses to the original posts.
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Test & Measurement
Post subject: UWB PA transmitted power and spectrum mask?
Posted: Wed Nov 30, 2005 9:30 pm
I have seen some
specificaiton stated that the spectrum mask of the UWB is -41.3dBm/MHz.
For the average Tx power is -10.3dBm. I want to ask how is the -10.3dBm
get? I am so trouble about these two values. Is it means that the transmitted
output power from PA must need to reach to -10.3dBm?
Post subject: UWB powerPosted:
Thu Dec 01, 2005 12:34 pm
In the US, these are legal maximum limits
- not required powers!
The spectral mask is there merely to assure
that the power is spread over the assigned bandwidth equally, which
will reduce interference with existing (licensed!) services. Please
notice the very low power: -10.3 dBm is 93.3 microwatts. This level
of power can often be generated directly, without the need for an amplifier.
Post subject: Posted:
Wed Jan 04, 2006 11:35 pm
Joined: Sat Dec
31, 2005 9:19 am
With a spectral density limit of -41.3
dBm/MHz the TX power of -10.3 dBm is a 30 dB difference. This means
the TX bandwidth is three orders of magnitude larger than the 1MHz spectral
density, so the -10.3 dBm TX power is for a 1GHz bandwidth (-10.3 dBm/GHz).
For UWB the maximum bandwidth is 7GHz for the 3-10 GHz band so the
maximum TX power allowed should be about -2.8 dBm.
Post subject: Posted:
Tue Jun 26, 2007 1:40 pm
Joined: Tue Jun
26, 2007 10:27 am
Location: Dallas, TX
802.15.3a the specification states that the maximum transmit power for
a UWB signal is -41.3 dBm/MHz. Each UWB band is 528 MHz as stated in
the MB-OFDM proposal (which has seemed to take over compared to the
DS-CDMA proposal). There are 14 band groups allocated in the UWB proposal
located from 3.1 to 10.6 GHz, but right now most companies and researchers
are only concerned with what is called "Mode I" of UWB which focuses
on the 3 band groups located between 3.1 and 4.7 GHz. Therefore, we
calculate the maximum average transmit power for a Mode I UWB device
-41.3 + 10*log10(3*528)= -9.3 dBm
we operate at 1 dB backoff to make sure we stay below the FCC regulation
and we end up with a maximum transmit power of -10.3 dBm.
we talk about average transmit power for all 14 bands with a 1 dB power
backoff we will obtain:
-41.3 + 10*log10(14*528) - 1 = -3.6