Patent ID: 7206740

Claim:
In a Noise Feedback Coding (NFC) system operable in a ZERO-STATE condition and a ZERO-INPUT condition, the NFC system including a long-term noise feedback filter having a first filter memory and a short-term noise feedback filter having a second filter memory, a method of updating the first and second filter memories, comprising: (a) producing a first ZERO-STATE contribution to the first filter memory and a second ZERO-STATE contribution to the second filter memory when the NFC system is in the ZERO-STATE condition; (b) producing a first ZERO-INPUT contribution to the first filter memory and a second ZERO-INPUT contribution to the second filter memory when the NFC system is in the ZERO-INPUT condition; (c) updating the first filter memory as a function of both the first ZERO-STATE contribution and the first ZERO-INPUT contribution; and (d) updating the second filter memory as a function of both the second ZERO-STATE contribution and the second ZERO-INPUT contribution.