Transfer Standards To briefly review, a frequency calibration compares the device under test (DUT)to a reference. The DUT is usually a quartz, rubidium, or cesium oscillator. Thereference is an oscillator of higher performance than the DUT or a transfer standardthat receives a radio signal.13).Calibration MethodsTo review, frequency standards are normally calibrated by comparing them to atraceable reference frequency. In this section, weâll discuss how this comparison ismade. To begin with, letâs look at the electrical signal produced by a frequencystandard.
Further information: Factitious diarrhea. The most common cause of melanosis coli is the extended use of laxatives, and commonly anthraquinone containing laxatives such as Senna, Aloe Vera and other plant glycosides. The anthranoid laxatives pass through the gastrointestinal tract unabsorbed until they reach the large intestine, where they are changed into their active forms.
The following medical conditions are some of the possible causes of Cyanosis. There are likely to be other possible causes, so ask your doctor about your symptoms. 1  Cyanosis.  Some other causes of blue skin include: