Not just for Televes, they are just one manufacturer of aerial related items.
A notch filter will allow most radio signal through but severely attenuate (weaken) frequencies for a very narrow band - usually enough for 1 channel to be "notched" out. Similar products are low pass filters (all below a certain frequency), high pass filter (guess!) and band pass filters (a range of channels allowed through, like a wide notch filter in reverse).
An attenuator reduces the level of a signal (radio in this context). Sometimes a signal is so strong that it causes problems for a receiver by overloading the front end (first bit of the receiver). This can cause interference problems with your desired signal. Reducing the signal strength, sometimes of the desired signal as well, can allow the desired signal to get through without distortion.
A line amplifier boosts the strength of a radio signal to overcome losses in the connecting cable. They also boost the noise in the signal and introduce a certain amount noise of their own so should be used with extreme caution. They are usually NOT the answer to problem.
PaulR