Constraints are placed on the designer on all sides by a power factor target plus all of the usual factors of efficiency, component cost, and board space occupied. This means good measurement is needed to optimize the design. Simple multimeters will usually misread to some extent when presented with distorted waveforms. A digital multimeter may make a good effort at reporting the RMS value of even a moderately distorted waveform, but it will be challenged to record power factor. An oscilloscope with current and waveform probes can be used to gauge the phase-shift, but only if the voltage and current wave-shapes are reasonably similar. Precision electromechanical meters that directly measure power factor aren’t suitable for tracking down the effects of kHz or MHz regulator switching in an advanced PSU. Instead, specialized equipment is now needed. These power analyzers rapidly sample current and voltage waveforms and perform a suite of calculations before applying a Fourier transformation to extract harmonic information. By doing this, every detail of a load's performance in terms of distortion and power factor can be revealed.