Sign
Properly, loss quantities, when expressed in decibels, should be positive numbers. However, return loss has historically been expressed as a negative number, and this convention is still widely found in the literature.
Taking the ratio of reflected to incident power results in a negative sign for return loss;
- where RL'(dB) is the negative of RL(dB).
Return loss is identical to the magnitude of Γ when expressed in decibels but of opposite sign. That is, return loss with a negative sign is more properly called reflection coefficient. The S-parameter S11 from two-port network theory is frequently also called return loss, but is actually equal to Γ.
Caution is required when discussing increasing or decreasing return loss since these terms strictly have the opposite meaning when return loss is defined as a negative quantity.
Read more about this topic: Return Loss
Famous quotes containing the word sign:
“Whether he admits it or not, a man has been brought up to look at money as a sign of his virility, a symbol of his power, a bigger phallic symbol than a Porsche.”
—Victoria Billings (b. 1945)
“Grant me the treasure of sublime poverty: permit the distinctive sign of our order to be that it does not possess anything of its own beneath the sun, for the glory of your name, and that it have no other patrimony than begging.”
—St. Francis Of Assisi (c. 1182–1226)
“The radio ... goes on early in the morning and is listened to at all hours of the day, until nine, ten and often eleven o’clock in the evening. This is certainly a sign that the grown-ups have infinite patience, but it also means that the power of absorption of their brains is pretty limited, with exceptions, of course—I don’t want to hurt anyone’s feelings. One or two news bulletins would be ample per day! But the old geese, well—I’ve said my piece!”
—Anne Frank (1929–1945)