The signal generator is an electronic device that induces repetition and non-repetition of analog or digital signals.
The signal generator is widely used in troubleshooting, signal tracing, testing, amplifier response tuning, and radio and TV circuit alignment.
The signal generator has a built-in modulation property. Amplitude and modulation properties are very common in signal generators.
The signal generator’s block diagram is represented in the graphic below. A VCO is the major component of the signal generator (voltage controlled oscillator). The frequency of the VCO is determined by the input control voltage.
The control voltage has a strong connection with the VCO frequency. The frequency of the oscillator is determined by the signal provided to the control input. When the audio input signal is placed across the control voltage, the VCO produces a frequency modulated signal.
Tone, arbitrary, and digital waveforms are generated by the signal generator. The fundamental distinction between a signal generator and an oscillator is that signal generators create the changed output signal alongside the other signal.
The signal is considered to be creating a continuous height wave signal when it creates unmodulated signals. Produces square waves, triangular waves, complex signals, and other modulated signals.
The modulator circuit is put after the VCO for frequency modulation. The AM output signal is produced by changing the VCO output voltages.
Types of Signal Generators
Analog Signal Generator:
The analogs base the production of all types of waves on the triangular one. The triangle wave is produced by the charging and discharging of a capacitor. The voltage fluctuates up and down due to the change in the capacitor’s charge. A comparator (an electrical device that compares two voltages or currents and changes its output to indicate which is higher) reverses the process of charging and discharging the capacitor when the voltage reaches its greatest and minimum levels. This comparator also allows the generation of the other types of waves. By varying the current and the size of the capacitor, different frequencies can be obtained.
Otherwise, there are a lot of analog types that can generate the basic types of electrical waves: sinusoidal, square and triangular.
Digital Signal Generator:
This equipment allows the generation of digital wave functions (sinusoidal, rectangular, triangular and pulses) from the DDS system (“direct digital synthesis”) and by means of a phase accumulator and a digital to analog signal converter (CDA). The frequency range is 0.001 to 20 MHz with a resolution of 6 digits or 1 mHz, and the amplitude is variable, between 5 mV and 20 V, peak to peak, for an impedance of 50-600 W.
Digital signal generators use a D / A converter to generate the waveform from values stored in memory. Typically these generators only supply sine and square signals at maximum frequencies and triangular signals and other waveforms at much lower frequencies.