Patent ID: 7653448

Claim:
A NICAM processing method comprising: receiving and temporarily storing a current frame of A-channel and B-channel input data into a first memory at a first clock rate; reading companded A-channel and B-channel data of a previous frame from a second memory at a second clock rate and in a manner for interleaving the previous frame companded A-channel and B-channel data into the NICAM standard required interleaved format, the companded A-channel and B-channel data of the previous frame having been temporarily stored during a previous frame into the second memory in a format other than an interleaved format according to NICAM standard requirements, wherein the second memory includes a first RAM and a second RAM, and wherein the format other than the interleaved format according to the NICAM standards comprises a dual word pre-interleaved format, and wherein each dual word of the dual word pre-interleaved format comprises 22-bits of a companded A-channel word and a companded B-channel word pair, and wherein each dual word is stored in one of the first RAM or the second RAM, and wherein the reading the companded A-channel and B-channel data of the previous frame from the second memory comprises: (i) reading a first dual word from an address of said first RAM and a second dual word from an address of said second RAM, wherein said address of said first RAM and said address of said second RAM have a same address value, (ii) extracting a bit from a first word of the first dual word and a bit from a second word of the second dual word to form a dibit, wherein the bit from the first word is a MSB of the dibit and the bit from the second word is the LSB of the dibit, and (iii) repeating the reading and extracting until all dibits contained within the second memory have been read and extracted, wherein the read and extracted dibits together form a bit stream of 704 bits of interleaved and companded A-channel and B-channel data according to NICAM standard requirements; and companding the A-channel and B-channel input data of the current frame and storing the companded A-channel and B-channel input data of the current frame into the second memory and in the format other than the interleaved format, wherein the companding and storing are performed at a third clock rate during an interval within the current frame that occurs subsequent to both the storing into the first memory and the reading from the second memory.