How referrals work. A referral from your primary care physician can cover a period from 90 days to one year. Referrals for oncology, rheumatology and renal management are issued for one year. Your primary care physician will let you know when your referral is approved, or Blue Care Network will send you a letter in the mail.
Infinite impulse response (IIR) filters. IIR filters are the most efficient type of filter to implement in DSP (digital signal processing). They are usually provided as biquad filters. For example, in the parametric EQ block of a miniDSP plugin, each peak/notch or shelving filter is a single biquad.
UV filter. An L39 UV filter with a 55mm filter thread. A UV filter was used to protect the lens from damage. UV filters are individual compounds or mixtures that block or absorb ultraviolet (UV) light. UV filters are used in sunscreens to protect skin or in photography to reduce the level of ultraviolet light that strikes the recording medium.