distortion of the ground and ripples.

If you feed a sine wave through an amplifier that isn't exactly linear, the output will be distorted, not a pure sine wave.

Distortion is the defect where the output from a device does not mirror the input.

A distortion analyzer is an electronic test instrument that measures the accuracy of an electronic circuit at reproducing a wave. For instance, an audio amplifier might have a sine wave input to it, and the distortion analyzer measures how close the output is to a sine wave. If the output is clipped, the wave will be distorted, and the analyzer will measure the amount of harmonics present.

The analyzer does this by supplying a low distortion sine wave test signal which is connected to the device under test. The output from the device is connected to the input of the analyzer where the original input signal is filter out with a precision notch filter. Anything left over after filtering represents distortion components and noise. Amplifiers will frequently have a "Total Harmonic Distortion plus Noise" specification which is an accurate term for the quantity measured by a distortion analyzer.

There are many manufacturers of distortion analyzers. The Hewlett-Packard models 331a and 333 are laboratory standard instruments. Other notable manufacturers are Sound Technology Corporation and Textronix.

fundamental wave component is filtered in the front end.

distortion refers to any deviation in any parameter like amplitude,time shape of an electrical signal from an ideal input signal.the distortion occurs due to the inherent non-linear characteristics of the component and devices that form the electronic circuit cause some harmonics to take place in the waveform and resultant deviation is know as harmonic distortion.