ML6415 S-Video Filter with Summed Composite
Output, Sound Trap, and Group Delay Compensation
GENERAL DESCRIPTION
The ML6415 is a dual Y/C 4th-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 to notch-out audio, pro-
viding an area for the addition of the FM audio carrier(s)
and mimic the group delay distortion introduced at the
transmitter. The group delay predistortion compensates
for the nominal TV receiver IF filter distortion.
In a typical application, the Y and C input signals from
DACs are AC coupled into the filter. Both channels have
DC restore circuitry to clamp the DC input levels during
video sync. The Y and C channels use a separate feedback
clamp. The clamp pulse is derived from the Y channel.
The outputs are AC coupled. The Y, C, CV, and modulator
outputs can drive 2Vp-p into a 150Ω load (1Vp-p 75Ω
coax load). The Y, C, CV, and notch channels have a gain
of approximately 2 (6dB) with 1Vp-p input levels.
FEATURES
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7.1MHz Y and C filters, with CV out
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14dB notch at 4.5MHz for sound trap
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42dB stopband attenuation at 27MHz on Y, C, and CV
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Better than 1dB flatness to 4.5 MHz on Y, C, and CV
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RF Modulator output differential group delay between
3.0MHz and 3.58MHz is typically -170ns.
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No external frequency select components or clocks
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9ns group delay flatness on Y, C, and CV output
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5% overshoot on Y, C, and CV output edges
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AC coupled inputs and outputs
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0.4% differential gain on Y, C and CV channels, 0.4º
differential phase on Y, C and CV channels
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0.8% total harmonic distortion on all channels
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DC restore with low tilt
APPLICATIONS
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Cable Set-top Boxes
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Satellite Set-top Boxes
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DVD Players
DATASHEET
June, 2000
MICRO-LINEAR [ MICRO LINEAR CORPORATION ]
