8121C loudspeaker aging tester

1、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 much flatter frequency response than using 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’s spectrum, including White Noise, Pink Noise and three kinds

of “Weighted Noise”, conforms to following nation’s standards:

(1) JIS C5531, IEEE 219, CNS 4785

(2) EIA 426B(3) DIN 45573

2、Since the Noise Generator (Model-8121C) is mainly designed for loudspeaker testing,thus, it is equipped with a 50W or 100W power amplifier, and “TRUE RMS” voltage measuring circuit , to measure the “TRUE RMS” of output noise. Never use a general VTVM, AC millivoltmeter or a digital voltage meter to measure noise voltage, unless

when these meters have specially noted that its AC testing function is a TRUE RMS mode,otherwise, the testing result of RMS value is only precise for a sinusoidal signal, because these meters are designed for sinusoidal RMS voltage testing. If these meters are used to test nonsinusoidal signals (including noise signals), the results of measured RMS

values will be inaccurate, therefore, the 8121C is equipped with “TRUE RMS” testing circuit, to measure the noise output voltage. Since noise voltage itself is not highly stable, thus,the voltage meter’s indicator needle will have a slight deflection, don’t mistake this as 8121C was faulted.