FIXED QUALITY SOURCE CODER

摘要

A fixed quality source coder (20) receives and performs VQ on an input signal ID. The fixed quality source coder (20) includes an encoder (28) and may also include a decoder (34). The encoder may include a lossy codec (52) that receives and encodes the signal ID to provide encoded information (38) to a multiplexer (30) regarding the signal ID. The lossy codec (52) also decodes the encoded signal to produce a decoded signal IVQ<-1> (62). A summer (66) receives ID and IVQ<-1> and determines an error signal ER (70) where ER equals ID - IVQ<-1>. A threshold circuit (74) receives the signal ER and passes a truncated error signal ET'. The threshold level T may be set to ensure that the maximum error allowed in the encoder (28) is equal to a particular desired maximum error.