On 2/25/2021 5:16 PM, John Kaufmann via Topband wrote:
The P3 averages power, not amplitude, so using longer averaging times just smooths the display and doesn't reduce random noise.
It has nothing to do with power. Last I looked, the P3 is reading and displaying the instantaneous voltage in the IF, and can be calibrated to voltage at the input.
I've been doing swept measurements of complex quantities for nearly 40 years, first at audio frequencies and now at RF. Averaging DOES cause random contents of a bin to approach zero (or the noise floor), making correlated signals stand out. This has long been well understood.
I the principle to measure the dynamic response of broadcast signal processing in a peer-reviewed paper to the Audio Engineering Society in 1986. The test signal was a swept sine embedded deep in musical program material to the point that it was barely audible to a trained listener, and detected by a synchronized swept narrowband detector. Because the swept excitation and swept detector are synchronized, the measurement produces the complex response of the system, and program material, being non-coherent, averages out.
http://k9yc.com/AESPaper-TDS.pdf 73, Jim K9YC _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
