Patent ID: 7233966

Claim:
A device ( 1 ) for generating a digital output signal (y LOG (k)/K) as a mathematical function of a digital input signal (x LOG (k)), comprising a level-changing device ( 6 ) which by amplifying or attenuating the input signal (x LOG (k)) generates a first intermediate signal (A) that falls within a compressed argument range of said mathematical function, and a correction signal (Shift LOG ) that depends on the amplification or attenuation of said input signal (x LOG (k)), a storage device ( 20 ) in which function values of said mathematical function are stored at or between indices (x i , x i+1 ; y i , y i+1 ), the tabulated function values (B 1 ) being read from said storage device ( 20 ) in dependence on said first intermediate signal (A) and a second intermediate signal (B) being generated in dependence on the read tabulated function values (B 1 ), and a correcting element ( 12 ) that generates said digital output signal (y LOG (k)/K) by correcting said second intermediate signal (B) by means of said correction signal (Shift LOG ), wherein an interpolator ( 30 ) generates interpolation values (B 2 ) in dependence on the deviation of said first intermediate signal (A) from said indices (x i , x i+1 , y i ,y i+1 ), and an adder ( 29 ) sums said tabulated function values (B 1 ) and said interpolation values (B 2 ), and wherein in said interpolator ( 30 ) a linear interpolation is performed using increases m const 1 , m const 2 , m const 3 ) that are each constant within segments (I 1 , I 2 , I 3 ) of said compressed argument range, and a switchable multiplication system ( 31 ) is provided that multiplies a multiplier (A-ADR-Δx/2) corresponding to the deviation of said first intermediate signal (A) from reference positions ((x i + x+1 )/2, (y i , y i+1 )/2)) defined by the indices (x i , x i+1 , y i , y i+1 ), depending on the segment (I 1 , I 2 , I 3 ) in which said intermediate signal (A) is located, by the constant increase (m const 1 , m const 2 , m const 3 ) appertaining to the segment (I 1 , I 2 , I 3 ) concerned.