Abstract: An apparatus and method for automatically adjusting a gradient of a reset ramp waveform of a plasma display panel in order to automatically adjust a ramp waveform generated in a reset period contributing to deviation adjustments between circuit components and between panels are provided. The apparatus manufacturing process is simple and the reset ramp waveform gradient is automatically adjusted, without manually adjusting the reset ramp waveform gradient, by sensing image information related to a gradient adjustment of the reset ramp waveform of the plasma display panel through a sensor and automatically generating a ramp waveform of a most suitable gradient based on the sensed image information.

Abstract: A method of performing an inverse discrete cosine transform (IDCT) capable of reducing the amount of calculation while satisfying bit accuracy required by international standards. The IDCT method comprises the steps of defining each column of scalars X.sub.ij (where, i,j=0,1,2, . . . , N-1) and Y.sub.ij as a vector X.sub.i ={X.sub.i0, X.sub.i1, . . . , X.sub.i(N-1) } and a vector Y.sub.i ={Y.sub.i0, Y.sub.i1, . . . , Y.sub.i(N-1) }, respectively, storing values of ##EQU1## in a scalar register, storing values of X.sub.i ={X.sub.i0, X.sub.i1, . . . , X.sub.i(N-1) } in a vector register, obtaining Y.sub.i ={Y.sub.i0, Y.sub.i1, . . . , Y.sub.