Signal processing apparatus for adding synchronizing signal to horizontal and vertical blanking periods of a color difference signal

摘要

A signal processing circuit for adding a synchronizing signal to a predetermined signal, wherein the synchronizing signal oscillates to one side from a reference level of the synchronizing signal, and wherein the predetermined signal oscillates to one side from a reference level of the synchronizing signal, and wherein the predetermined signal oscillates to one or both sides from a reference level of the predetermined signal. The signal processing circuit includes a synchronizing signal adding circuit for adding the synchronizing signal to the predetermined signal, and a signal level adjusting circuit for adjusting the reference level and the amplitude of the synchronizing signal, wherein the signal level adjusting circuit makes the reference level of the synchronizing signal substantially identical to the reference level of the predetermined signal, and also makes an amplitude of the synchronizing signal with respect to the reference level thereof larger than the maximum deviation of the predetermined signal from the reference level thereof.