The main function of a digital signal processor (DSP) is to perform real-time processing of digital signals. DSPs are used in a wide variety of applications, including audio and speech processing, image processing, and telecommunications. They effectively convert analog signals into digital form and perform computations to manipulate these signals for various purposes, such as noise reduction, compression, and filtering. The efficiency of DSPs makes them essential in devices like smartphones, audio equipment, and automotive systems, where high-speed processing and accuracy are crucial.