Real-time development of a DSP-based ringing detection and warning system

Epilepsy is a neurological condition in which the electrical activity of groups of nerve cells or neurons in the brain becomes disturbed. This type of disease can cause muscle spasms, and loss of consciousness in the patient. Several factors can contribute to the triggering of seizures. Among these factors are external stimuli such as flashing lights or sudden changes from dark to light, or loud noises. This paper will focus on the development of a real-time DSP system that will assist a patient suffering from epileptic seizures that are triggered by loud and sudden telephone rings. It has been observed, however, that if the patient is forewarned of the impending occurrence of the rings he is able to prepare himself for the event and avoid a seizure. Therefore, the system developed in this project provides the ring detection and advanced warning needed by the patient. Since different rings are typically characterized by strong sinusoidal components present at different frequency bands, a Sub-band Adaptive Filter Detector (SAFD) will be used. The SAFD will divide the input audio signal spectrum into frequency bands that will be evaluated separately for the purposes of extracting any periodic component present in the incoming audio signal. This paper will discuss the offline performance of this system as well as the performance of the hardware implementation.