Kunnal,

A few common digital signal processing historically done using 8051 technology:

1)Digitally Controlled Oscillators and Arbitrary Waveform generators;
2)Digitally Controlled or implemented Filters;
3)Audio Delay Lines;
4)PolaPulse and other types close proximity SONAR ranging;
5)Servo and Micro-Stepping Motor Control,

Regards,
p