Sony G90 manual IEV Turboscan 1500 Line Doubler, Remote Control, Line Doubling = Deinterlacing

IEV Turboscan 1500 Line Doubler

Any home theater that uses a CRT front projector capa-

ble of graphics- or data-grade resolution needs a way

to reduce the visibility of scan lines and remove inter-

lace artifacts, which become painfully unpleasant on a big

screen. Until recently the devices (line doublers) for doing

this with credible quality have cost over $7,500. For my own

modest home theater, with a 7-inch CRT front projector and 6-

foot wide screen, this price was beyond budget. My first pri-

ority was to find a way to convert the YPbPr component video

outputs of my DVD player to work with the RGB inputs of my

projector. I also needed input switching for my laserdisc and

VCR viewing.

The least expensive YPbPr-RGB converter, without line

doubling, is about $900 from Extron. I was about to buy one

of these when I discovered the $2,495 IEV Turboscan 1500 line

doubler. This unassuming black box performs the conversion

I needed, has switching functions, and does line doubling.

This remarkable device also includes separate adjustment of

video parameters (brightness, contrast, color, tint, and sharp -

ness) for each input, and overall adjustment for red, green,

and blue gain and offset levels. The former is important to me

for matching the slightly different output levels of my

laserdisc player to those of my DVD player. The latter is use-

ful for fine control of color temperature, especially for a pro-

jector like mine that doesn’t have digital controls for this func-

tion. Imagine my delight to find all of these features in a box I

could afford!

Description

The back panel of the Turboscan sports an on/off switch (nor-

mally left on), a power plug input, and a large array of video

input/output connectors. The composite and S-Video inputs

include buffered loop-through outputs. There is also an RJ-11

connector for a remote infrared control (IEV can supply this

or you can buy from a third party) and an RS-232 connector

for computer control of the unit (RS-232 programming com-

mands are in the manual).

My only complaint is that the VGA input connector

should be female, not male. All the readily available con-

nector cables, including VGA to 5-conductor BNC, or com-

puter to VGA monitor, terminate in a male VGA connector.

To use these on the Turboscan you have to use a female-to-

female adapter, creating a potentially unstable connection.

For an RGB input, the Turboscan can automatically

detect whether it is already progressive (as all computer

VGA outputs are) or whether it is interlaced; it can also be

forced into one or the other state. Thus I set up the Tur-

boscan to accept a computer signal on the VGA input con-

nector (which also includes my 3Dfusion progressive DVD

player) and pass that through without dou-

bling. For laserdisc, I use the S-Video input

and for cable TV (via a VCR tuner) I use the composite

input.

The front panel of the Turboscan is clean, showing only

asmall LCD panel and a touch panel control with left-right-

up-down arrows. The menu commands, displayed on the

LCD panel or on a simple onscreen block, are logically

linked in a circle, all accessible by the left-right arrows on

the front panel or the remote.

Remote Control

The Turboscan 1500 has many features beyond its line dou-

bling capability, most of which I have already mentioned. As

supplied by IEV, it comes with the excellent Home Theater

Master SL-8000 universal remote that includes the control

codes for over 500 devices (audio, satellite, TV, VCR, cable,

CD, DVD, and auxiliary). My Turboscan, along with my Elec-

trohome projector, came from Hi Rez Projections, Inc., of

Boston (www.hometheater1.com), which include Home The-

ater Master’s better remote, the SL-9000 with learning capa-

bilities. Both these units are wonderful, exceeded only by

remotes costing several hundred dollars.

Line Doubling = Deinterlacing

The name “line doubler” is misleading. These devices don’t

increase the total number of scan lines per video frame.

They deinterlace conventional NTSC video by replacing

each interlaced video field, which alternately displays only

the odd or even half of the frame’s scan lines, with a pro-

gressive video frame containing all of the scan lines. Dein-

terlacing is a complex process because the fields from a

video camera represent the image at different moments in

time. Simply merging fields together would create double

images of objects in motion, while interpolating new lines

between existing lines of each field produces a softer image.

Deinterlacing video sources is where most line doublers fall

down, the IEV included. That is not to say that it does a bad

job, though.

Film sources are converted to video by a telecine device

that repeats video fields at regular intervals, to convert the

24-frame-per-second film to 60-field-per-second video. This

is called 3-2 pulldown and creates an opportunity for a line

doubler to detect this pattern and reverse the process to

generate progressive video. For many years, only Faroudja

had special patented circuits to detect film sources with 3-2

pulldown and perform an inverse-telecine process to ideally

deinterlace them. (See Issue 24 for details of the inverse-

telecine process.) The Turboscan does not have inverse-

telecine deinterlacing and must process both video and film

sources using other techniques. The question is, how well do

they match up to the Faroudja standard?

The IEV Turboscan 1500 performs well with

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