Channel coupling for an AC-3 encoder

A signal processor for a coupling process having:

• first and second coupled channel register;
• a coupling channel means for combining frequency coefficients of the first and second coupled channel;
• a coupling coordinate calculation means including:
• normalization means for analyzing mantissas of the frequency coefficients in a channel band in each of the channels, the normalization means producing first normalization values for each respective channel represented by a prescribed number of reduced bits;
• calculation means for determining a sum of the square of values for each channel;
• shifting means for post-shifting each sum to obtain a power value for each of the channels;
• divider means for providing a mantissa quotient by dividing the post shifted sum of the first and second coupled channels by the post shifted sum of the coupling channel, reduced to a prescribed number of reduced bits;
• and
• a lookup table for providing square root values of the mantissa quotients, the square root values representing a mantissa component of the coupling coordinate of each of the first and second coupled channels.

A signal processor for a coupling process for use with a first coupled channel, the signal processor comprising:

• normalizing means for normalizing frequency coefficients of the coupled channel to produce mantissas with respective normalization values represented by a prescribed reduced number of bits;
• calculating means for calculating a sum of the square of the values;
• and
• post-shifting means for post-shifting the resultant sum to obtain a power value of the coupled channel.