The effect of modulation broadening on the shape of the Fourier coefficientaoLdescribing an unsaturated, Lorentzian absorption line is examined theoretically and experimentally. An unusual feature, not previously observed, is the development of two equal maxima when the normalized modulation amplitude (1/&bgr;) exceeds (2)1/2. Expressions are derived for the position and amplitude of these maxima as a function of (1/&bgr;). Experimental evidence confirming these expressions is presented.