S parameters of port in DB Опции

[sergei94]

when we calculate S parameter in DB

DB is a ratio what ratio takes plase in the S parameters measure?

thanks

[Hale]

one note.
dB generally has no physical quantity, which makes it convenient to use between people interested in amplitudes and powers. So, the basic rule is dB=10log10(P/Po)=20log10(A/Ao). Obviously, 2 comes from square of amplitude. Since S-params are about amplitude, it is "20". But in measurements, when treating detected envelopes etc. you often take it with "10xlog" from the screen data.
dBm, dBc, dBa etc, are just relative cases with different Po for different measurements.

Сообщение отредактировал Hale - Feb 3 2017, 01:10