Sine Wave Generator

A sine wave generator is a class of functional generators that produce a sinusoid-shaped waveform or signal.  The sine wave is continuous with a smooth periodic oscillation. It is one of the most simple and basic waveforms. The waveform repeats itself after every 360°. Some modern sine wave generators use digital signal processors to synthesize waveforms. Digital waveforms can be converted to the analog equivalent by passing them through digital to analog converter.

Sine Wave Generator
Sine Wave Generator

Construction

There are so many waves in the cosmos and so are the sources. Natural waves are diverse and more complex and account for very vital processes undergoing in the universe. This post will limit itself to artificial waves of the sinusoid shape. At the heart of this generator is an oscillator that is triggered to generate waves. Most signal wave generators mostly have an oscillator that is calibrated in frequency and amplitude. Additionally, they have a non-linear diode shaping circuit. The generator has terminals to control all characteristics of a signal. Modern sine wave generators have microprocessors control and will allow operation from a personal computer. They may be free-standing, self-contained instruments or may be incorporated into more complex automatic test systems.

Operation

The operation highly depends on construction, that is the various components used. The simplest sine wave is generated by ac electric power generator. The varying magnetism that cuts across conductors generates varying induced current that is sinusoidal in shape. So yes, the ac electricity is a sine wave. For equipment-generated waves, this is one of the circuits used. A square wave is first generated by switching the dc source on and off repeatedly. the consecutive switching on has the polarity reversed such that positive and negative cycle alternate. The square wave comprises any other shape of a wave that is may be desired. They derive a sine wave, an LC circuit is used. The square wave is passed through an inductor and resistor in parallel. The exchange of energy between capacitor and inductor gives rise to positive and negative cycles of a sine wave. The size of the capacitor and inductor determines the frequency while the magnitude of the square wave determines the output amplitude.

Another method of generation is as follows. At first triangular waveforms are generated by charging and discharging capacitors repeatedly from a constant current source. This produces a linearly ascending and descending voltage ramp. As the output voltage reaches upper or lower limits, the charging or discharging is reversed using a comparator, producing the linear triangle wave. By varying the current and the size of the capacitor, different frequencies may be obtained. A non-linear diode shaping circuit converts the triangle wave into a reasonably accurate sine wave by rounding off the corners of the triangle wave in a process similar to clipping in audio systems.

Properties of a good sine wave generator

  1. Produces smooth sine wave.
  2. Ability to generate a wide range of frequencies.
  3. Frequency stability of 0.1 percent per hour for analog generators or 500 ppm for a digital generator.
  4. Maximum sinewave distortion of about 1% (accuracy of diode shaping network) for analog generators.
  5. Supports Amplitude modulation (AM), frequency modulation (FM), or phase modulation (PM) may be supported.
  6. Output amplitude up to 10 V peak-to-peak without clipping.
  7. Amplitude can be modified, usually by a calibrated attenuator with decade steps and continuous adjustment within each decade.
  8. Have provision for DC offset voltage, e.g., adjustable between -5V to +5V.
  9. An output impedance of 50 Ω.

Conclusion

From the physics world, there are two broad branches of study, i.e. matter and waves. Electricity, light, sound, wind, and aroma are all waves. All communication whether near or far involves the transmission of a wave signal. The medical field depends heavily on signal generators in-lab diagnosis. Research equipment has signal generators that help scientists to carry out tests. The one that cannot be left out is that generators are a useful stimulus in the designing, testing, troubleshooting, and repairing of electronic devices. You may be interested in learning other types of wave generators, stay tuned.

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