What is Waveshaping? – Types

Waveshaping is a part of signal processing where the signal waveform has to be properly shaped before amplification. It may be defined as a process of generating new waveforms from older 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 alteration of a triangular wave into a square wave, and vice versa, alteration of a square wave into a series of narrow pulses, alteration of a square or triangular wave into a sinusoidal wave, and alteration of a sinusoidal wave into a square wave. This 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 waveshaping and nonlinear waveshaping.

In linear waveshaping, signal shape is altered by transmitting it through a linear network—a network consisting of linear elements 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 circuits 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 waveforms such as step-pulse, square, ramp and exponential waveforms.

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