Abstract: Due to unavoidable timing and slope errors in the leading and trailing edges of invert pulses utilized in encoding and decoding of the television signal by inversion of the picture signal portion relative to the synchronizing signal portion, transients are generated. A clamping circuit clamps the television signal to a predetermined reference level for short time intervals around each desired switching time instant. The time intervals are sufficiently long to include the maximum possible variation in the actual timing of the switching time instants. A grey level is thus inserted at the encoder. At the decoder, a clamping circuit clamps the television signal to ground potential during the grey level intervals thereby balancing the DC components of the signal portions.