4-line Digital Comb Filter V.s 3D Comb Filter


Just tried an Advent 27" HDTV "HT2751A"
(4-line Digital Comb Filter) and a Samsung 27" TXN2775HF (3 line filter), the picture of Advent is SIGNIFICANTLY BETTER and cleaner, espectially when I watch a reagular TV program. The Samsung's picture is very very dirty(lots of snow), much worth than my 5 years old 19" Zenith.

Went back the store to return the Samsung,a sales guy told me that the Samsung TXM2798HF
use "3D Comb Filter" which will be much better when watch regular Tv.

My question is:4-line Digital Comb Filter,3D Comb Filter,3 line filter which is better??


I found this in a buyer's guide, doesn't say anything about 4 line...

A 3D Y/C (also known as 3D Digital Comb Filter) is the best type of comb filter available today. In addition to separating the Y (black and white) and C (color) elements of a video signal, a 3D Y/C filter performs two additional key functions. While comparing three consecutive horizontal scan lines within a single video frame, it also analyzes each frame in advance, ensuring the best possible picture.

A 3-Line Digital Comb Filter separates the Y and C signals while simultaneously processing three consecutive horizontal scan lines. This type of comb filter does not pre-analyze individual video frames.

A 2-Line Digital Comb Filter separates the Y and C signals while simultaneously processing two consecutive horizontal scan lines.

Analog Comb Filters are found on less expensive large-tube televisions and on models smaller than 27". The two most common types are CCD (charge coupled device) Comb Filters, found on more recent models, and Glass Comb Filters, which are not as common today.

jj51, don't get hung up on the comb filter in your buying decision. The comb filers are used only on the antenna and composite inputs. S-Video, RGB (VGA), Component and Firewire already have the color and brightness signals seperate and the comb filter has no effect.

PAL (video standard for much of Europe) often uses a 4 line comb filter, I am not sure how it works compared with a 3 line comb filter for NTSC.

Many 3D comb filters can be considered to be 4 line comb filters, processing at any given time the current scan line, the scan line immediately preceding, the scan line immediately following, and the scan line in the previous frame corresponding to the current scan line (525 scan lines back).

for what it's worth...
The Advent HD tv can display in 480 lines and the Samsung regular tv can only display 240 (interlaced). The HD doesn't really need comb filter for DVD since it displays every line. For TV, I believe it does a interpolation of the line above and below. Much better than any comb filter (since the comb filter is an attempt to simulate the missing interlace line and the 480 tv already has the 480 lines) which is why you like the picture much better.

What you are describing is the difference between interlaced and progressive. Comb filters are only used to separate the color signal from the black and white signal. See

An HD set may not need a comb filter only if a standard definition RF or composite signal never reached the set.

Sony KV36FS100
This tv has up to 1080i on hi-scan. It has component video input and I want to know if this tv is hdtv ready and if I can buy a converter. Time warner currently makes a hdtv box that has component out. Can I use it? Is there a great difference between hi-scan circuitry (1080i) and hdtv (1080i)?

if it says HDTV monitor that means you have to buy a receiver to convert the signal. If it just says HDTV than it should have the receiver built in but you should always ask before purchase.

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