Patent ID: 8443016

Claim:
A method implemented in a signal processing apparatus for approximating an upper-bound limit for the absolute value of a complex number or the norm of a two-element vector, wherein the signal processing apparatus includes an upper bound function circuit, the method comprising: providing a complex number having a real part and an imaginary part associated with a signal to be processed; computing a first absolute value of the real part and a second absolute value of the imaginary part; through the upper bound function circuit of the signal processing apparatus, computing an upper-bound limit from the first and second absolute values, wherein computation of the upper-bound limit by the upper bound function circuit comprises: comparing the first absolute value against the second absolute value to determine which of the first and second absolute values has a relatively smaller value, and which of the first and second absolute values has a relatively greater value; computing a product result of multiplying the smaller value with a constant parameter; and obtaining the upper-bound limit as a result of adding the product result with the greater value; computing a third absolute value of the complex number; and through the upper bound function circuit, comparing the third absolute value against the upper bound limit to detect the occurrence of an overflow condition.