signal level(n = noun.attribute) - the amplitude level of the desired signal;
is a kind of amplitude

a level, abney level, air level, amplitude level, background level, background signal, biosafety level, biosafety level 1, biosafety level 2, biosafety level 3, biosafety level 4, block signal, blood-oxygenation level dependent functional magne, brightness level, carpenter's level, college level, distress signal, dumpy level, electronic signal, energy level, fog signal, frost signal, fuel level, ground level, groundwater level, input signal, intensity level, level, level at, level best, level crossing, level head, level off, low level flight, mason's level, nautical signal flag, noise level, o level, on the level, output signal, plumb level, poverty level, pressure level, price level, radio signal, radiotelegraphic signal, sea level, signal, signal box, signal caller, signal detection, signal fire, signal flag, signal light, sound pressure level, spirit level, split level, starting signal, storm signal, support level, surveyor's level, telegraphic signal, threshold level, time signal, traffic signal, turn signal, visual signal, wake-up signal, warning signal, water level, weather signal, wind signal, y level