A simplified hardware for adaptive closed caption data slicing

A CMOS shift register is used to slice and store the closed caption data from the NTSC line 21 video signals, which is adaptively shifted by the DC output of a pulse width modulator. The adaptive data slicing algorithm is achieved with the use of a high speed microcontroller. Using these two simple digital devices, a prototype general RISC microcontroller that can be used to control all functions of a closed caption TV receiver is constructed without the need for dedicated hardware.