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.
internal rate of return (IRR) One of the two discounted cash flow (DCF) techniques (the other is net present value or NPV) used in comparative appraisal of investment proposals where the flow of income varies over time. IRR is the average annual return earned through the life of an investment and is computed in several ways. Depending on the method used, it can either be the effective rate of interest on a deposit or loan, or the discount rate that reduces to zero the net present value of a stream of income inflows and outflows.