WAVESHAPING

 waveshaping is a part of a signal processing where the signal waveform has to be properly shaped before amplification.It may be defined as a process of generating new waveforms by employing some network.In this process the output may vary in shape from input because of influence of the circuit elements on the signal.The influence of the circuit elements is determined by the ratio of output to input amplitude , and by the phase angle between the output and the input.Examples of waveshaping include alternation of a triangular wave into a square wave, and vice versa,alteration of a square wave into a series of narrow pulses,alternation of a square or triangular wave into a sinusoidal wave,and alternation of a sinusoidal wave into a square wave. Waveshaping  techniques are widely used in function generators,frequency synthesizers,and synchronization circuits that need different waveforms having precisely the same frequency.
Waveshaping may be of two types viz linear and non-linear waveshaping.
In linear waveshaping, signal  shape is altered by transmitting it through a linear network-a network consisting of linear element such as R,L and C.If a sinusoidal signal is applied to a linear network,then,in the steady state,the output signal will have the same waveshape as the input signal,though it may have amplitude and phase angle different from those of original signal.This feature of a sinusoidal signal to preserve its shape in all linear networks is unique.Thus R-C,R-L and R-L-C circuits are categorized as linear waveshaping circuits.such circuit are used to perform differentiation,integration and summation functions.
In nonlinear waveshaping,the shape of a signal is moderated by transmitting it through a nonlinear network.Nonlinear network consists of circuit elements having nonlinear transfer characteristics,such as diode,transistor,vacuum tube,in conjunction with other linear circuit elements.such circuits find application in amplitude limiting,clipping and clamping of signals.
In pulse circuitry there are many non-sinusoidal waveform such as step-pulse,square,ramp and exponential waveforms.
   

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