Does this refer to a mobile phone network?
It seems that this signal can refer to a wide range of concepts, just like in English. E.g. electrical signal - 电信号, digital signal - 数字信号, turn signal - 转向信号. So (as far as I've seen), in the context of information.
信号 is so badly pronounced that it is heard like 写好! The audio is seriously corrupted here.
It seems to be working fine now, 12/29/2019