Sony DVP-NS999ES - Manual (Page 13)

ES Series DVD-Video/CD/SA-CD Players; Version 3.0 Page 13
For progressive scanning, running the D/A converter at the minimum
frequency of 27 MHz makes it extremely challenging to design the
analog low-pass filter. The filter (red curve) must be steep to avoid
cutting into the video signal (blue) or including some of the noise (pink).
The solution to this problem is to run the A/D converter at a higher
frequency than 27 MHz. This process shifts the aliasing noise up in frequency,
opening up substantial room between the video signal and the noise. With more
room, we can relax the design of the analog filter, which can be far milder in
slope, and far more effective at optimizing both the picture detail and the picture
clarity.
Oversampling at the 108 MHz frequency of the DVP-NS999ES makes a
huge difference. Now the noise is far removed from the video signal. A
gently sloping analog filter can effectively control noise while delivering
all the video detail to your television.
Oversampling has been used successfully in CD players for decades.
And while the video equivalent is harder to achieve, the effect is the same. The
D/A converter of the DVP-NS999ES shifts the sampling frequency from the
standard 13.5 MHz to 108 MHz. For progressive scan playback, that's 4x
oversampling. For interlaced playback, it's a whopping 8x oversampling.
Signal Loss
27 54 81 108 135 162 189 216
Frequency in MHz
27 MHz Sampling, Progressive Scan
Video
Signal
Noise Noise Noise Noise Noise Noise Noise Noise
Analog Filter
Noise included with signal
27 54 81 108 135 162 189 216
Frequency in MHz
108 MHz Sampling, Progressive Scan (DVP-NS999ES)
Video
Signal
Noise Noise
Analog Filter
Noise well separated from signal
Full detail of signal retained