Abstract: Improvement of the signal-to-noise ratio for a wideband video signal is effected by subtraction from the wideband video signal of a signal which follows low-amplitude excursions of the video signal's high frequency component. The latter signal is formed by a circuit arrangement which includes a high pass filter, of a C-R differentiator form, coupled to the input of an amplifier. A negative feedback path, coupled between the amplifier output and the junction of capacitive and resistive elements of the differentiator includes threshold devices which permit activation of the negative feedback path only during input signal excursions which exceed selected close-to-axis limits.