Similar circuits are still used in professional audio equipment (compressors, limiters and noise suppressors). Terry also started to develop signal processing hardware including compressor/limiters and small graphic equalisers. Inrush current can also be reduced by inrush current limiters. The compressor and limiters are ways of controlling the loudness of a track. The study provides objective data on what limiters and compressors do to the audio signal. These limiters may also retard the ignition timing. Some vehicle categories have various lower maximum limits enforced by speed limiters. Some modern consumer electronics devices incorporate limiters. First invented by Howdon Torque Limiters in 1978. Some proposed requirements include CCTV cameras, Panta Transportation Payment Terminal, speed limiters and GPS monitors. Some applications use limiters for component protection and gain structure control. Also some supercars have speed limiters to prevent instability. Some automatic cannons have larger burst limiters to coincide with higher rates of fire. Rockets have none of these inherent combustion temperature limiters. Rev limiters are pre-set by the engine manufacturer.