FIXED QUALITY SOURCE CODER

摘要

A fixed quality source coder receives and performs VQ on an input signal ID. The signal ID may be characterized by the number of samples/frame and bits per sample, and may be provided by a traditional source coder. The traditional source coder may include a sample-and-hold (S/H) circuit producing rxs samples/frame and an ADC providing n bits per pixel. In a first embodiment, the number of bits/sample is increased. In the second embodiment, the number of samples/frame is increased. In a third embodiment, both the number of bits/sample and the number of samples/frame are increased. Measurements made in simulations involving the first and second embodiments show that the fixed quality source coder has a smaller data rate, mean absolute error (MAE) and root mean square error (RMSE) than that of the traditional source coder, while maintaining the same or less maximum error. The fixed quality source coder includes an encoder and may also include a decoder. The encoder may include a lossy codec that receives and encodes the signal ID to provide encoded information to a multiplexer regarding the signal ID. The lossy codec also decodes the encoded signal to produce a decoded signal IVQ-1. A summer receives ID and IVQ-1 and determines an error signal ER, where ER may equal ID-IVQ-1. A threshold circuit receives the signal ER and passes a threshold signal ET, where a threshold level T may be set to ensure that the maximum error allowed in the encoder is equal to a particular desired maximum error.