Expressions for the intensity distribution in the diffraction images of a general triangular wave-object have been obtained. The diffracting aperture considered is an aberration-free annular aperture. The circular aperture system appears as a particular case when the obstruction ratio is zero. Use of incoherent light has been assumed throughout. General triangular wave response of such systems to spatial frequencies in the object has been plotted and the object function, which gives a wave response nearly similar to that of the sine wave, has been pointed out.