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 the noise spectrum, including White Noise, Pink Noise, and three kinds of Weighted Noise, that conform to the following nations standards:(1) JIS C5531, IEEE 219, CNS 4785 (2) EIA 426B(3) DIN 45573 1. White Noise: -3dB Bandwidth: 20Hzï½?100kHz, Roll off:-24dB / Oct. Flatness: �±1dB 2. Pink Noise: -3dB Bandwidth: 20Hzï½?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: