N=kTB = -174dBm/Hz (@290K)
So says every reference and application note I have ever read. NIST says this is wrong and it should be -177dBm/Hz.
http://tf.nist.gov/phase/noisemeas.html
I am curious as to the ramifications of this change on test instrumentation such as spectrum and noise figure analyzers, calibration of noise sources, etc.
Does Agilent have an application note or document that clarifies this discrepancy?
So says every reference and application note I have ever read. NIST says this is wrong and it should be -177dBm/Hz.
http://tf.nist.gov/phase/noisemeas.html
I am curious as to the ramifications of this change on test instrumentation such as spectrum and noise figure analyzers, calibration of noise sources, etc.
Does Agilent have an application note or document that clarifies this discrepancy?
All Agilent application notes regarding noise figure measurements all list kTB at -174 dBm/Hz. It seems every Google search on the web also agrees. There is some good information on Thermal Noise in Agilent application note 57-1 in the Glossary on page 26. In order for this value to change from -174 dBm/Hz, one of the three variables in kTB must change. Was it Boltzmann’s constant, temperature or bandwidth, which is referenced to 1 Hz?
The ramifications around test equipment would be huge.