The 1381 Random-Noise Generator generates truly random noise from a semiconductor source. The generated noise is flat down to 2Hz and is intended for random-vibration tests and for general-purpose use in the audio and sub-audio range. The upper frequency limit (@3 dB) can be switched to 2, 5, or 50kHz. Output level is adjustable from below 3 mV to 3 V rms (600 ohms impedance) and can be clipped symmetrically at 2, 3, 4, or 5 times the rms amplitude.