Sound and vibration level recorders for field use

Abstract

Level recorders are widely used to measure the wide range analog level of noise and vibration. The conventional level recorder is sometimes inconvenient for the field measuring because of its size. With respect to the dynamic characteristics, this type recorder basically differs from the sound level meter conforming to ANSI and IEC standards. Especially in case of short duration signal input, there is large difference between them. The main reason is that the pen of the level recorder responds to the input at a constant speed, while the needle of a sound level meter deflects exponenially. The two newly developed level recorders have the pen response characteristics coinciding with the indication of a sound level meter, and is very convenient for use in the field accompanying a sound level meter because of its internal battery operation, smaller size, and lighter weight. One of these is specialized for the level recording adopting the dc servo mechanism, the other is for level and waveform recording adopting the high‐speed response multi‐pin‐head recording system.