AN113 Phase Angles and Time Delays

As a prerequisite to this Application Note, the reader is encouraged to examine Dataforth's Application Note AN112, Reference 2, which describes the amplitude characteristics and reviews the analytical techniques of low-pass filter frequency dependent transfer functions associated with Dataforth's signal conditioning modules' filter circuits.

Internal filtering enhances sensor signal integrity of signal conditioning modules (SCM) by eliminating undesirable frequency and noise components. However, the inherent characteristic of this type of filtering functionality adds a phase angle with an associated propagation delay to the original signal. This added phase and delay does not generally affect steady state low frequency industrial process measurements. However, in some situations, near instantaneous changes in process variables need instant recognition. In these situations, one should carefully examine SCM specifications to determine their applicability. Dataforth SCM specifications include pulse transient data to assist selection. Visit Dataforth's website, Reference 1.