Function Generators, Wave-Shaping Circuits

By Mallesham Devasane|Updated : September 11th, 2016

Function Generators

  • A Function Generator generates different voltage signals, such as Sine, Pulse, Triangle.
  • The most commonly required signals in electronic circuits are Sine and Pulse.
  • Sine wave signals find their use mostly in Analog circuits, such as amplifiers, filters, etc.
  • Pulse signals are useful in testing the time response of circuits and also as Clock signals in Digital circuits.
  • In a general pulse signal, the high and low level time periods are different. Square wave is a special case when the periods are equal.


Wave-shaping circuits

Timing circuits networks composed of resistors, capacitors and inductors are called linear network and they do not change the waveform of a sine wave when it is transmitted through them. On the other hand when non-sinusoidal waveforms, (e.g. step, ramp, exponential) are applied to the input of such networks the output signal may have very little resembles with the input waveform. The action of a linear network in producing a waveform at its output different from its input is called linear wave shaping.

  • Shaping circuits may be either series RC or series RL circuits.
  • The series RC and RL circuits electrically perform the mathematical operation of integration and differentiation.
  • Therefore, the circuits used to perform these operations are called integrators and differentiator.
  • The differentiator circuits are used to generate sharp narrow pulses either from distorted pulse waveform or from rectangular wave forms.
  • The integrator circuits are required to generate a voltage, which are required to generate a voltage, which increases or decreases linearly with time.

The wave shaping is used to perform any one of the following functions.

  • To hold the waveform to a particular d.c. level.
  • To generate one wave form the other.
  • To limit the voltage level of the waveform of some presenting value and suppressing all other voltage levels in excess of the present level.
  • To cut-off the positive and negative portions of the input waveform.

Non-sinusoidal Waveforms: Any waveform whose shape is different from that of sinusoidal wave is called a non-sinusoidal waveform.

  • Step Function: A step function shown makes an instantaneous jump from one steady value to another steady value. A step means an instantaneous change in level.
  • Ramp Function: A ramp function is one that voltage increases or decreases linearly with time.
  • Exponential Function: An exponential function is a function of voltage that increases or decreases exponentially with time.


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