Patent ID: 7035328

Claim:
A method of slewing a bandwidth characteristic of a digital filter within a range between a fast bandwidth characteristic and a second bandwidth characteristic, said digital filter including a plurality of cascaded filter sections, each of said sections having respective coefficients, wherein each of said filter sections is comprised of a second order filter having coefficients a 1 , a 2 , b 0 , b 1 , and b 2 , said method comprising the steps of: determining an index value for identifying a desired bandwidth characteristic within said range; interpolating values for said coefficient values for said a 1 and a 2 coefficients of a respective filter section in response to said index value; deriving coefficient values for said b 0 , b 1 , and b 2 coefficients in response to said coefficient values for said a 1 and a 2 coefficients such that said b 0 , b 1 , and b 2 coefficient values provide a matched unity gain for said respective filter section; and loading said coefficient values into said respective filter section; wherein said digital filter is a low pass filter and wherein said b 0 , b 1 , and b 2 coefficient values are determined according to the relationships: b 1 =0.25+0.5 ·a 1 +0.5 −a 2 ; b 0 =b 1 ÷2; and b 2 =b 0.