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?
subject: UWB powerPosted: Thu Dec 01, 2005 12:34 pm
In the US,
these are legal maximum limits - not required powers!
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
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
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
For IEEE 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 as follows:
-41.3 + 10*log10(3*528)= -9.3 dBm
Then, 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 dBm