Hello,
Our EMC testing laboratory recently purchased an E4407B with most of the bells and whistles from Agilent (this summer). We are using the analyzer and have run into a few issues / functions that we are wondering can be added at the firmware or other level. We have the instrument configured with the Quasi Peak adapter, low frequency extension and low resolution bandwidth options among others. When we make measurements above 1 GHz the regulatory agencies would like us to make the measurements of signals in two modes. First a Peak mode measurement using 1 MHz RBW and 3 MHZ VBW. We are also required to make an "Average Mode" measurement where we use 1 MHz RBW and 10 Hz VBW. Currently the analyzer limits the VBW to 30 Hz instead of ten. Can this be changed in the firmware of the instrument, or are there more complicated issues in order to accomplish this. Thanks in advance.
Larry Stillings
Compliance Worldwide, Inc.
Our EMC testing laboratory recently purchased an E4407B with most of the bells and whistles from Agilent (this summer). We are using the analyzer and have run into a few issues / functions that we are wondering can be added at the firmware or other level. We have the instrument configured with the Quasi Peak adapter, low frequency extension and low resolution bandwidth options among others. When we make measurements above 1 GHz the regulatory agencies would like us to make the measurements of signals in two modes. First a Peak mode measurement using 1 MHz RBW and 3 MHZ VBW. We are also required to make an "Average Mode" measurement where we use 1 MHz RBW and 10 Hz VBW. Currently the analyzer limits the VBW to 30 Hz instead of ten. Can this be changed in the firmware of the instrument, or are there more complicated issues in order to accomplish this. Thanks in advance.
Larry Stillings
Compliance Worldwide, Inc.
The limitation that you are experiencing is due to the fact that Video bandwidths in the ESA series less than 30 Hz are digitally implemented as are Resolution bandwidths less than 1 kHz. Because of the difference in the implementations it isn't possible to mix them, nor would it be possible for us to change the instrument firmware in order for this to work.
One other thing that you will notice if you are using the Average (Video/RMS) detector is that if you do not have a video bandwidth 3 times wider than the resolution bandwidth you will get the "Meas Uncal" message on the screen. When you get this in this case you are not really getting an accurate RMS detection, as the video signal is being filtered before it reaches the ADC, and the RMS averaging is done after the ADC. So, you are affectively video averaging the data before the RMS average detector can get its hands on it. Of course, maybe the standard that you are using is taking this into account, I don't know...
I hope this helps,
Mike