... measurement,AC/DC signal output 2.fast/slow time weighting 3.30 years manufacturing experience TL5633B digital sound level meterIt meets IEC ... , GB/T3785 standard and the second class sound level meter standard of JJG188-2002 sound meter verification regulations.It is suitable for ... .3v , changes according to 0.1v/10dB, load impedance 1MΩSound calibration TL 6020 ( 94dB,1000HZ)Power DC 7v-9v, with ...