| 摘要 |
PURPOSE:To prevent noise due to crosstalk at a horizontal synchronizing signal by outputting a signal not applied with emphasis and a signal subject to emphasis while being switched, selected and syntehsized at a horizontal synchronizing signal period and a video image period. CONSTITUTION:A luminance signal Y after a band pass filter is delayed by tau1 at a delay circuit 22, inputted to a pre-emphasis circuit 5 as a signal YD and becomes an output YP. The YD is led to an input terminal 23b of a switching synthesis circuit 24 through a lead 25. The outputs TP, YD are switched and synthesized during a prescribed period by using a switching signal X1 fed to the circuit 24 and led to an FM modulator 26. A switched and synthesized output YS formed at it is led to an output terminal 27 as an FM luminance signal YFM having a frequency in response to the signal level. Furthermore, a luminance signal Y is inputted to a synchronizing separator circuit 4, a horizontal synchronizing signal HS from the signal Y and the pulse at the synchronism tip, i.e., a horizontal synchronism pulse HP is inputted to a pulse width expanding circuit 28. |
