If the temperature is below setpoint, the output will be on longer; if the temperature is too high, the output will be off longer. The third controller type provides proportional with integral and derivative control, or PID.
Amplifier figures of merit. In electronics, the figures of merit of an amplifier are numerical measures that characterize its properties and performance. Figures of merit can be given as a list of specifications that include properties such as gain, bandwidth, noise and linearity, among others listed in this article. Figures of merit are important for determining the suitability of a particular amplifier for an intended use.
are sometimes expressed in NC (Noise Criterion) ratings. Concert halls and recording studios aim for ambient noise level ratings of NC-15 to NC-20; NC-15 is considered the lowest level that is feasible to achieve outside the laboratory. I hope this gets you started in the right direction!