Please help me figure this out==>
PXA in spectrum analyzer mode is used for this measurement.
Start Freq 1.75GHz
Stop Freq 2 GHz.
Sweep time Manual => 200 msec.
Detector RMS
# of sweep points =>2001.
RBW Auto 3MHz.
Average ==> Log average
My Radio is transmitting 6 C as follows (Freq in MHz)
1805.2 1812.2 1819.2 1826.2 1833.2 1840.2. Each carrier has 40 dBm of power (Verified using the PVT mode measurement)
When I put a marker in any of the above frequency,PXA marker is showing 5 to 6 dB less power. Since the carrier BW is only 200 KHz and RBW is 3 MHz with RMS detector, PXA should give the correct power of 40 dBM, right. Please let me know what I am missing here.
PXA in spectrum analyzer mode is used for this measurement.
Start Freq 1.75GHz
Stop Freq 2 GHz.
Sweep time Manual => 200 msec.
Detector RMS
# of sweep points =>2001.
RBW Auto 3MHz.
Average ==> Log average
My Radio is transmitting 6 C as follows (Freq in MHz)
1805.2 1812.2 1819.2 1826.2 1833.2 1840.2. Each carrier has 40 dBm of power (Verified using the PVT mode measurement)
When I put a marker in any of the above frequency,PXA marker is showing 5 to 6 dB less power. Since the carrier BW is only 200 KHz and RBW is 3 MHz with RMS detector, PXA should give the correct power of 40 dBM, right. Please let me know what I am missing here.
It sounds like you have a bursted signal that is transmitting only part of the time. When using the RMS detector, the power will be averaged over the entire time that the analyzer acquires samples at each trace point. If the duty cycle of the signal is 25%, then you should expect the measured power to be 6 dB lower than the on-time power. For the span of 250 MHz and sweep time 200 ms and 2001 sweep points, each trace point bucket is 250 MHz / (2001 -1) = 125 kHz wide. The acquisition time for each trace point bucket is 200ms / 2000 = 100 microseconds. Over a 100us time period, what percentage of the time is your signal burst on? This will let you know how much the measured power will be reduced by. For a bursted signal you can turn on time gating and only make measurements during the on-time of the burst. This would give you the same results as measured when using the Power Vs. Time measurement.
Regards -