Symbol Meaning: "+" Enclosed in a Circle

[nimitzhunter]

Hi,
I am reading this paper and it has a symbol that I don't know what it's called. So for an x enclosed in a circle, it represents an analog multiplier. What does a "+" enclosed in a circle mean? I know it's add the analog signal, but what is it called?

 

[berkeman]

Hi,
I am reading this paper and it has a symbol that I don't know what it's called. So for an x enclosed in a circle, it represents an analog multiplier. What does a "+" enclosed in a circle mean? I know it's add the analog signal, but what is it called?

Welcome to the PF.

I'd just call it an analog adder:

http://www.mossbauer.org/images/Trends4.gif

.

 

[Jiggy-Ninja]

In other words, it's symbolic shorthand for a http://www.electronics-tutorials.ws/opamp/opamp_4.html" ? Or what?

 

[nimitzhunter]

I think I get what it's used for. It's like amplitude modulation where you add together analog signals.