Ultrasound is commonly used for medical diagnostics such as sonograms. CPCs that qualify as medical clinics may provide pregnancy testing, sonograms, and other services. CPCs that qualify as medical clinics may also provide pregnancy testing, sonograms, and other services. These differences are sometimes minute, often detectable only in the sonograms. These visual representations are also called sonograms or sonagrams. Most of the sonograms were prepared from Robbins's own field recordings. The calls can be distinguished by sonograms. Sonograms can also be roughly converted back into sound.