Electronic signal and Radar echo

Electronic signal noun - A signal generated by electronic means.

Radar echo and electronic signal are semantically related. In some cases you can replace phrase "Radar echo" with "Electronic signal", this phrases are similar.

Radar echo noun - An electronic signal that has been reflected back to the radar antenna; contains information about the location and distance of the reflecting object.

Electronic signal and radar echo are semantically related. You can use "Electronic signal" instead a noun phrase "Radar echo".