odular Precision Sound Level Meter Type 2231 is a Type 1 precision instrument in accordance with IEC 651 regulations. It can perform a wide range of measurements, and can be used with a variety of modules. The characteristics of the sound level meter depend on the module that you most recently loaded into it - the module’s software, transferred to the sound level meter, adapts the instrument to particular needs. The nature of the measurements that you require will determine those needs. In general, when the sound level, meter receives a signal, it performs several measurements simultaneously (for example, Peak and EMS detection). Therefore, you can look at the Peak and RMS values of the same measurement. A very wide frequency range of 1 Hz to 70kHz allows measurements in the infrasound and ultrasound regions. Depending on the module loaded, the sound level meter can perform several special functions, including automatic print-out of data at the end of preset time periods. These print-outs can be in any one of six languages. The sound level meter can also communicate with, and be controlled from, a computer. The sound level meter has three polarization voltages. This means that you can use almost any Bruel & Kjaer Microphone. "With Microphone Type 4133 plus extension cable AO 0027, the sound level meter becomes a Type 0 instrument, in accordance with IEC 651 recommendations. Features of the Type 2231 Sound Level Meter include: ■ Fulfils IEC 804 Type 1, relevant sections of IEC 651 Type 11, and ANSI SI .4-1983 Type 1. ■ When used with Microphone Type 4133 and Extension Cable AO 0027, fulfills IEC 804 Type 0 and relevant sections of IEC 651 Type 0 I. WH 24 to 113dB(A)* measuring range (30 to 133dB(A)* with attenuator) in 7 overlapping sub-ranges. M 73 dB Pulse range; 70 dB RMS Linearity range. ■ RMS and Peak detection in parallel. ■ Internal memory has back-up battery power which prevents loss of application software and data when the instrument is switched off.