Detection of fatal transient impairments using an embedded secondary channel

It is desirable for voiceband data communication equipment to have an efficient transient channel impairment detector for fast recovery. One such detector is proposed for high-speed modems using a secondary channel synchronously embedded in the main channel. A known code word being multiplexed with the secondary port data is sent through the embedded secondary channel. The received code word is tested for detection of fatal transient impairments. For reliable detection, the confirmation is sequentially performed based on a modified up/down counter scheme. The performance of the proposed detector is analytically evaluated in closed form