Ripple and Noise measurementBTCPower AN01 Ripple and Noise Measuring Output Noise and Ripple Measuring output noise and ripple requires a basic understanding of the high frequency nature of noise. Very often, ‘noise’ (as commonly measured) is actually the vector sum of common and differential mode noise. Common mode noise is common to both outputs ( i.e +OUT and -OUT) with respect to chassis or earth ground. Differential mode noise is found at one output with respect to the other. While the system load can be affected by differential mode noise, it is seldom affected by common mode noise. The common mode noise is often only created in the process of measuring the differential mode noise. Noise can be measured as root mean square (RMS) or peak to peak. Low frequency noise with a low peak to average ratio is often m……