Model-8121C uses a logic circuit to generate Pseudo Random Noise , it is the newest and the most advanced design to generate audio white noise. It has a much flatter frequency response than using a diode. Model-8121C has: (1)White noise source.(2)Weighting filters. (3)Built-in power amplifier. (4)�¢?? TRUE RMS �¢?? voltage meter circuit. It can generate five different kinds of noise spectrum, including White Noise, Pink Noise, and three kinds of �¢??Weighted Noise�¢??, that conforms to the following nation�¢??s standards:(1) JIS C5531, IEEE 219, CNS 4785 (2) EIA 426B(3) DIN 45573 1. White Noise: -3dB Bandwidth: 20Hz 100kHz, Roll off:-24dB / Oct. Flatness: �?�±1dB 2. Pink Noise: -3dB Bandwidth: 20Hz�¯�½?20 kHz Roll-off: -24dB / Oct. Crest factor: 4 ( IEEE 219 ) Amplifier: 1.100W output is defined at an unclipped maximum output of sine wave. 2.Frequency response : 20 Hz~20 kHz �±0.2dB; 20 kHz~100kHz �±1dB 3. Output: With permanent short circuit protection. Load Impedance: 3.2