Environmental Engineering Reference
In-Depth Information
Evaluation of harmonic distortion factors for the amplifier schematised in
Fig. 7.3a is straightforward. We can use (7.7) and (7.8) after noting that the
input signal of the nonlinear block is now
Hence, the distortion
factors are
Harmonic distortion referred to the amplitude of the output signal
fundamental component are formally identical to the last equations in (7.7)
and (7.8) except that now these expressions must be evaluated at the
frequency of the input signal (fundamental). Note that this also holds for
i.e., also the output signal must be calculated at the fundamental frequency.
Consequently, when we have to evaluate the frequency behaviour of
and
it is easier to refer to their formulations in terms of the input signal
The above equations give the magnitude of and as this is the
most common information required by designers. However, in their general
form these equations can be used to obtain also information on phase
distortion. In the following we will consider only the magnitude of distortion
factors.
