Patent ID: 7233893

Claim:
A speech signal transmitter comprising: a quadrature mirror filter for receiving a speech signal, dividing the speech signal into an enhancement band speech signal and a base band speech signal, and outputting the enhancement band speech signal and the base band speech signal; a base sub-band encoder for receiving and encoding the base band speech signal; an enhancement sub-band encoder for receiving and encoding the enhancement band speech signal; and a network connector for multiplexing the encoded enhancement band speech signal and the encoded base band speech signal based on the kinds of networks over which speech signals are transmitted, and transmitting the multiplexed signals to the networks, wherein the network connector simultaneously packets the enhancement band speech signal and the base band speech signal or packets only the base band speech signal, if the networks are composed only of networks guaranteeing or of networks not guaranteeing quality of service, and packets and transmits the base band speech signal to the networks guaranteeing quality of service and packets and transmits the enhancement band speech signal to the networks not guaranteeing quality of service, if the networks are composed of networks guaranteeing quality of service and networks not guaranteeing quality of service.