Signal generators (Signal Sources)...
...provide defined signals for testing technology in quality management, development/design, training/teaching etc. This test signal is used to stimulate a device under test. The output or the "reaction" of the DUT to the test signal is monitored and measured. Thus, the behaviour of the DUT can be analyzed. For this purpose, the signal generator must output a stable and "clean" signal with as little noise as possible. In order to create the most realistic simulation possible of the later application reality, the test signal of the generator should also come as close as possible to the later "real" signal or cover the relevant signal frequency range. In addition to a pure sine wave, other signal forms are often required for testing purposes, such as square wave, sawtooth/ramp and arbitrary signals.
Available signal generators can be subdivided depending on the frequency range and the signals generated:
RF sources: In most devices for the RF range, the test signal is a sine wave. The frequency range of these devices goes up from a few GHz up to 67 GHz and more. In this category of devices, vector modulations such as PSK, QAM, FSK, ASK play an important role in addition to the common modulations such as AM, FM, ØM or pulse modulation. In addition, they offer sweeping, where the frequency of the signal varies cyclically between two definable values.
LF signal generators: They operate in frequency ranges far below 1 GHz (for example 120 MHz, 350 MHz, 500 MHz or even less). Depending on the model, they deliver different signal forms, whereby most manufacturers distinguish relatively freely between three types:
Standard signals/functions ("function generator") such as sine, square/pulse, triangle/sawtooth/ramp, noise.
Fixed arbitrary signals such as cardiac, exponential rise/fall, Gauss pulse, Haversinus, Sinc etc.
User-loadable arbitrary signals. For these signals the memory of the device (signal length), its sample rate and resolution are important. In addition, many devices offer sequencing of signal segments.
Depending on the model, the LF generators also support different modulations and sweep operation.