FMS6406

www.fairchildsemi.com FMS6406 Precision S-Video Filter with Summed Composite Output, Sound Trap, and Group Delay Compensation Features 7.6MHz 5th order Y,C filters with composite summer 14dB notch at 4.425MHz to 4.6MHz for Sound Trap capable of handling stereo 50dB stopband attenuation at 27MHz on Y, C and CV outputs Better than 0.5dB flatness to 4.2MHz on Y, C and CV outputs Equalizer and notch filter for driving RF modulator with group delay of -180ns No external frequency selection components or clocks < 5ns group delay on Y, C and CV outputs AC coupled inputs AC or DC coupled outputs Capable of PAL frequency for Y,C,CV Continuous Time Low Pass Filters < 1.4% differential gain with 0.7° differential phase on Y, C and CV channels Integrated DC Restore circuitry with low tilt Description The FMS6406 is a dual Y/C 5th order Butterworth lowpass video filter optimized for minimum overshoot and flat group delay. The device also contains a summing circuit to generate filtered composite video, an audio trap and group delay compensation circuit. The audio trap removes video information in the spectral location of the subsequent RF audio carrier. The group delay circuit predistorts the signal to compensate for the inherent receiver IF filter’s group delay distortion. In a typical application, the Y and C input signals from DACs are AC coupled into the filters. Both channels have DC restore circuitry to clamp the DC input levels during video sync. The Y and C cha...