18-letter words containing p, a, s, f, i
- phase-shift keying — (communications) (PSK) A digital modulation scheme that conveys data by changing the phase of a carrier wave. The data can either determine the absolute phase relative to the unmodulated carrier or reference signal ("coherent phase-shift keying", CPSK) or the change in phase ("differential phase-shift keying", DPSK). The number of different phases used determines the amount of data that can be transmitted in each cycle. Each cycle can be considered to constitute one "symbol", e.g. with two possible phases, each cycle carries one bit. The more phases that are used, the less tollerant to noise the transmissions becomes. Alternatives to PSK are amplitude-shift keying (ASK) and frequency-shift keying (FSK).
- pilotless aircraft — an aircraft equipped for operation by radio or by robot control, without a human pilot aboard; drone.
- play second fiddle — be considered less important
- population figures — population totals; statistics relating to the size of populations
- potassium fluoride — a white, crystalline, hygroscopic, toxic powder, KF, used chiefly as an insecticide, a disinfectant, and in etching glass.
- presumption of law — a presumption based upon a policy of law or a general rule and not upon the facts or evidence in an individual case.
- prince of darkness — Satan.
- purchasing officer — the member of staff in an organization who is responsible for buying goods or products
- reinforced plastic — plastic with fibrous matter, such as carbon fibre, embedded in it to confer additional strength
- safety-deposit box — a lockable metal box or drawer, especially in a bank vault, used for safely storing valuable papers, jewelry, etc.
- saint peter's fish — another name for tilapia, taken from a Bible story about Saint Peter catching a fish with a coin in its mouth
- sampling frequency — sample rate
- seafloor spreading — a process in which new ocean floor is created as molten material from the earth's mantle rises in margins between plates or ridges and spreads out.
- self-contemplation — the act or process of thinking about oneself or one's values, beliefs, behavior, etc.
- self-deprecatingly — in a self-deprecating manner
- self-disparagement — the act of disparaging.
- self-preoccupation — the state of being preoccupied.
- self-tapping screw — a screw designed to tap its corresponding female thread as it is driven.
- soda-lime feldspar — plagioclase.
- spirits of ammonia — a 10% solution of ammonia in alcohol
- stepping-off place — jumping-off place (def 2).
- sweptwing aircraft — an aircraft which has wings that are swept (usually) backwards
- to play favourites — to display favouritism
- wild passionflower — the maypop, Passiflora incarnata.