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Any recent 5th generation receiver chip news? - Page 11

post #301 of 433
Thread Starter 
Well, there is lighting and thunder right now in the city where I live, and my digital OTA indoor reception is not affected at all. My 4th generation chip is not that bad, I guess.

post #302 of 433
I've never seen reception problems from thunder and lightning on local (within 60 miles) stations. Strong winds have caused problems, mostly from moving the antenna around. I suspect hi-VHF digitals have more trouble with this than UHF signals.
post #303 of 433
Originally Posted by inky blacks View Post

Well, there is lighting and thunder right now in the city where I live, and my digital OTA indoor reception is not affected at all.

LOL ... I'm not talking about your average garden variety storms ... I'm talking about the kind were you should really be heading for the basement or closet - the kind where that pesky, bandwidth stealin' radar sub channel is actually useful. Too bad it just doesn't work when you need it the most.
post #304 of 433
Originally Posted by HDTVChallenged View Post

I'm talking about the kind were you should really be heading for the basement or closet

This is the point my wife says, Honey, I can't watch HDTV. Go see if you can re-aim the antenna.
post #305 of 433
Originally Posted by the_bear89451 View Post

This is the point my wife says, Honey, I can't watch HDTV. Go see if you can re-aim the antenna.

ROTFL ... Good thing I wasn't sipping my coffee
post #306 of 433
Originally Posted by sregener View Post

I've never seen reception problems from thunder and lightning on local (within 60 miles) stations. Strong winds have caused problems, mostly from moving the antenna around. I suspect hi-VHF digitals have more trouble with this than UHF signals.

I've had HDTV OTA in Tampa for 4 yrs now. Used to be a Dish 6000 w/ OTA module, now HDTiVo. I've regulary experienced weather issues during storms on OTA channels, I just don't remember which channels, or whether any one channel is worse than ohters. The big 4 all have good reception on a clear day (all are located in an antenna farm about 30 miles away except CBS, which is about the same distance, but in almost the opp. direction; I have a sep atenna for CBS). The ABC and CBS channels are UHF, the FOX and NBC are VHF (actual channels 12 and 7).

Maybe when the current D* boxes (HDTiVo and Hughes HD box) get changed out for new mpeg4 boxes, the new boxes will have better tuners. I proably should also get my antennas pointed a little better, esp for CBS.
post #307 of 433
Originally Posted by HDTVChallenged View Post

LOL ... I'm not talking about your average garden variety storms ... I'm talking about the kind were you should really be heading for the basement or closet - the kind where that pesky, bandwidth stealin' radar sub channel is actually useful. Too bad it just doesn't work when you need it the most.

We get those kinds of storms here in Minnesota - and I've watched as a 'hook' formed on radar some 75 miles away - between me and the transmitters, and there was some signal breakup.

We've also had a genuine tornado pass between me and the transmitters some 30 miles away with nary a problem. (Channels 36 and 46)

Your problems are more likely wind related.
post #308 of 433
Originally Posted by sregener View Post

Your problems are more likely wind related.

Anything's possible ... I guess
post #309 of 433

- Just joined but have learned a lot already. Like My Samsung SIR-T351 is not so good with multipath. That is too bad for me, I thought maybe all STB are having the same problems.
- At first I didn't know what the heck was going on: 10 bars no bars, 10 bars no bars, Etc. etc. Then I heard or the term "multipath" AAAAAHHH!
- Well I have been tinkering around with a 7 foot satellite dish that I have rigged up for teresterial use, bow tie at or near focal point). It was no good at picking up Syracuse 70 road miles away, (my main goal), but it does help with my locals and multipath! I am thinking of hooking a rotor to it and moving it to the top of my barn. I am shooting thru lots of trees.
- Pardon my ignorance but who/what is LG?

post #310 of 433
LG is one of the world's largest electronics/appliances companies.

It's headqartered in Korea and is the owner of, among many other things,
the Zenith brand.

post #311 of 433
LG is one of the world's largest electronics companies. They are Korean (interesting how we never need to say "South" Korean). You have heard of them in the brand name they previously used, "Goldstar." LG stands for "Lucky Goldstar." They also own Zenith, who developed and owns ATSC patents. They wanted to distance themselves from the second or third rate quality image that the name Goldstar had developed. They make a very wide variety of products, including cell phones, TVs, microwaves, etc.

LG makes the best ATSC tuner available. They produced something referred to as the "fifth generation" ATSC tuner. I've read that it pretty much eliminates multipath problems, might allow reception in moving vehicles, is about 4 times as sensitive as previous tuners, and will allow the use of rabbit ears (yes, indoor antennas) for digital TVs for much of the population. It was so good, Sinclair, the bane of ATSC and 8VSB, the champion of COFDM, threw in the towel and said yes, it's very good.

Too bad you can't buy it. Well, OK, there seems to be an implementation of it in the DTV box sold at Wal Mart, but that STB has other shortcomings (like no DVI/HDMI). LG might put it into their TVs, and seems to be willing to license it. But there's not much of an STB market today, so companies aren't rushing this product out to market.

Meanwhile, probably the best STB you can buy is the LG 4200A. This is their "fourth generation" ATSC tuner. I have one, and yes, it's quite good.

on edit: once again, someone types faster than me! No replies when I started this post.
post #312 of 433
This past week I received my Digital Connections DVICO FusionHDTV5 with LG 5th generation chip. NICE! I don't have the horsepower on the computer to view HD with it (it is only a P3 850), but the SD streams are watchable. The big difference I saw was when it did a channel scan, it picked up stations that have good signal over my location, but because I use a CM4228 antenna, multipath prevents locks in certain directions. The Fusion5 for the first time told me there were signals there and in 80% of the cases, locked on the PSIP data. One station was 180 degrees behind my antenna and 90 miles to boot and the card told me there was a digital signal there. Movement of the antenna about 30 degreess and the PSIP data started showing up! No other receiver I have (I have a 2nd, 3rd and 4th generation receivers) has EVER told me there was a signal there unless I was pointing at the station. Same thing for a local low power station that I have to have the antenna pointed at to be able to pick it up.

I also was able to pick up off the side of the antenna several stations with PSIP data at 60 miles. WIth some movement of the antenna to increase the signal strength, but not directly on them as usual, their SD channel came in very watchable.

Just from these very rudimentary tests, I would say the LG 5th gen chip is a noticable improvement when it comes to multipath. Of course if you don't have the signal strength to start with, it is no better than any other receiver. I need need to get a P4 to run it and then try more experments.
post #313 of 433
Thanks for reminding me about the Fusion card. I'd forgotten about it. I have an ATI HDTV Wonder at home, but I might try the Fusion card for work, which is at a bit lower elevation.

You might also consider AMD chips- P4 is not the only option.
post #314 of 433

EIA/CEA-909 interface spec for Smart Antennas has been around for several years now.
It is described as being able to select up to 16 antenna directions and up to four gain settings.
Sounds like the solution to a variety of problems, especially for indoor reception.
Could find best direction among various multipath arrival angles and prevent overload.
Could solve difficult multiple arrival direction problems, such as we experience
here in San Diego with three different transmitter sites in SD plus three more in LA.
Especially if a Smart Antenna Preamp Module would accept external antennas.

Several of the newer ATSC tuner chips have implemented this interface, including
Broadcom's BCM3517, BCM3520 & BCM3560, STMicroelectronics STV0370,
and fol. ATI tuner chip's: THEATER 310, XILLEON 210 VC TVonChip, NXT2005 and
NXT2004 (used in Funai STB400E, Sylvania 6900DTE and Hisense/USDTV STBs).
And although HDTVWonder uses NXT2004, they seem to have begged off on CEA-909.

So where are all the HDTVs, STBs and Smart Antennas with CEA-909 interfaces???
Maybe because ATI holds the Smart Antenna patent:

The first demo seems to have been Nxtwave's prototype NXTENNA at NAB2002:
The photo shows a cylindrical object about 1 foot in diameter and 1-1/2 feet tall.
The description states that the gain control function was not used in the prototype,
but doesn't say very much else....like what mystery lurked within....

At the 2002 IEEE Broadcast Technical Symposium, ATI (who bought Nxtwave) described
a Smart Antenna implementation consisting of four log periodic dipoles [perhaps like four
stacked Silver Sensor's???] which are combined via preamplifers to scan sixteen compass
points in about 800 msec. [Perhaps that's what was in the NXTENNA cylinder???]

What followed was ATI's DTV5000 Smart Antenna demonstrated at NAB2003:
It appears to be a small, squat, triad kind of thingy....but I can't find a source...
[Maybe three small log periodics in order to reduce the cost???]

So the only EIA/CEA-909 Smart Antenna that I've seen so far is the DTA-5000,
as recommended in the Sylvania 6900DTE Spec sheet.
Here is link to DX Antenna (Japanese manufacturer) pdf spec sheet:
which appears to have evolved from DX Antenna's manually phased DTA-3500:
and the manually steered DTA-3000 (actually it's an RV roll-up antenna):

The DTA-5000 pdf spec sheet says that it is amplified (25 dB Max) with 16 "segments"
and notes that the 29 x 29 inch dimensions include the VHF antenna elements.
So it appears that there might actually be some UHF antenna gain in the unit,
although the VHF section is probably just a pair of low-gain crossed dipoles.
[Lets see, 16 minus 2 (or is it 4?) VHF "segments" leaves 14 (or 12?) UHF "segments".]
[So maybe 3-element Log Periodic's in each direction???]

There is only 10 dB of gain reduction, which is probably not enough close to transmitter towers.
[Q: Separate gain controlled preamp's or single preamp with PIN diode attenuators on each input? My guess would be the latter.]

Unfortunately the spec sheet remains silent on many important points.
It doesn't specify the Noise Figure and Max Output, which are probably in the ballpark
of the other DX Antenna products (1.5 to 4.0 dB with 95 dBuV max output level).

Note that the Sylvania STB talks to an external Control Module via a modular jack interface.
The RF signal from the Smart Antenna passes through the Control Module on the way to the STB.
Apparently the downlead is used to pass control information to the Smart Antenna from the Control Module,
but is NOT used for all of the control signals.
So why didn't they design it to pass ALL of the control data via the downlead???

And if this is supposed to be an indoor antenna, good luck to the user trying to camoflage it.
post #315 of 433
I just couldn't resist the lure of playing with Adaptive Antenna Arrays (AAA)....again.

The Sylvania 6900DTE OTA STB ($200 on-sale at Amazon) and associated DX Antenna DTA-5000 (the AAA for about $100) are on order....

Maybe I can attach some CM4221's (and/or a CM4228) to the internal antenna inputs....
post #316 of 433

I don't expect the DTA-5000 to be a "true" adaptive antenna array, since the ATI patent disclosure describes an exhaustive search through the various combinations of antenna direction and gain until it finds a "good" solution, with a discard algorithm to eliminate co-channel and adjacent channel interference conditions.

However, it is only one approach to improving reception under difficult propagation conditions.

Some of the better AAA's use a "true" diversity combiner implementation wherein the phases of the multiple antenna input signals are aligned (after downconversion) and then a Maximal Ratio Combiner (MRC) is used to sum them together, with each input weighted by a measure of the "goodness" of reception for that channel.

Depending on the algorithm and the number of antennas/receivers channels,
these "true" AAA's are capable of steering a beam towards the desired direction and/or a null towards undesirable interference.

Inexpensive "true" diversity receivers using Maximal Ratio Combiners (MRC) are commonly available for wireless microphones.

Dual and Quad-diversity mobile TV receivers for analog NTSC are also readily available,
(check Crutchfield's website for "TV Tuners" for cars ).
But since I haven't seen any descriptions with "true" or "MRC" in them,
they are probably using switching diversity techniques that would not yield any gain from the multiple antennas.

Multiple Antenna Diversity Receivers (aka "AAA") are also available to dramatically improve DVB-T mobile reception in Europe:
post #317 of 433
Originally Posted by holl_ands View Post

The Sylvania 6900DTE OTA STB ($200 on-sale at Amazon) and associated DX Antenna DTA-5000 (the AAA for about $100) are on order....

Let us know how it goes ....
post #318 of 433
Yes please let us know how this works out.
post #319 of 433
I'm interested in your results with the DTA-5000 as well. I have a friend who is trying one out as well and will post on that. I'm in the DC market, and even using this model indoors without a lot of effort, my friend was picking up Baltimore stations that were never available with other indoor antennas. This looks like it could have some potential, especially when I need to replace my UHF only outdoor antenna to pick up VHF channels once the transition completes.
post #320 of 433
Inside the DTA-5000 Smart Antenna from DX Antenna of Japan:

Although earlier smart antenna demos at NAB were described as using four log periodic
antennas, what I found inside looks like 2-element Yagis (i.e. director and reflector)
that can be configured to point North, South, East and West. By combining the
variable gain preamp outputs from adjacent antennas, sixteen compass points can be
tested to see which one provides the "best" reception. Since it's a compact
antenna structure, despite the LRC "traps" and inductors trying to make it
electrically "bigger", I would guess that the UHF gain is probably in the same
range (3 dBd) as the Zenith Silver Shadow and Terk HDTVi indoor antennas.
And the VHF gain is probably about the same as amplified rabbit ears, except
you don't have to readjust them.

I'll be posting comparisons of the DTA-5000 to a 4-Bay antenna both indoors and outdoors
in the near future, using an RF attenuator prior to the STB input to determine the amount
of "attenuation reserve" for each configuration. I'm about half-way through the sequence.
It's holding it's own against the higher gain 4-Bay and of course doesn't have to be rotated.


Sylvania 6900DTE with DTA-5000 Smart Antenna RevA.zip 459.791015625k . file


DTA-5000 Smart Antenna Pics.zip 495.3017578125k . file
post #321 of 433
After being out of stock at Wal-Mart's website for a while -- and with reports coming in that Wal-Mart stores were clearing out their USDTV receivers -- the USDTV receiver is back in stock at Wal-Mart's website.

Could this be the much-anticipated 5th gen box?

Description and model number follow (including a puzzling reference to "DVD quality"):

"For under $200, enjoy digital-quality television right now, on any TV. And if you have an HDTV (High Definition) television, you'll get an amazing DVD-quality picture, too. Receives digital and HDTV signals in widescreen 16:9 or normal 4:3 format. Also provides Dolby Digital 5.1 surround sound.

"Model No. DB-2010, HD Receiver"
post #322 of 433
The Hisense/USDTV DB-2010 OTA STB is last years model, currently under $200 at Walmart.
It has Component Video but does not have a DVI/HDMI interface.

For about the same amount of money, you can order the Sylvania 6900DTE which has DVI.
And an EIA/CEA-909 Smart Antenna interface if you want to try it with the DTA-5000
(and perhaps other Smart Antennas in the future.)

Both STB's use the ATI NXT2004 ATSC decoder chip, the same as the ATI HDTV Wonder
and Philips TU1236 ATSC Tuner Module and similar to the NXT2003 (which adds QPSK receiver)
used in "most" cable-ready HDTV's on the market today (per ATI press release).

If you read the description in the zip file above, you will find that ATI claims exceptional
operation of their equalizer with 0 dB pre and post echo levels and dynamic multipath
(just like 5th Gen LG), so NXT2002/2003/2004/2005 series are also high performance
devices derived from the NxtWave prototypes. I've see a Comptek Tuner spec sheet
that claimed -8us to +45us, using the NXT2004, although test conditions were not stipulated.

The 5th Gen LG may or may not provide better performance. Unfortunately there is very
little lab or on-air comparison tests available. Also note that the software needs to
be carefully tweaked in order to extend the equalizer delay capability well beyond the
baseline guidelines found in ATSC A/74 (-10 us to +40us under "typical" conditions).

I have yet to see any on-air justification for going to -40us with +60-80 us echos,
other than that they are (finally) going to double length equalizers that
initialize with the first received signal being "centered" in the equalizer.
It is possible that the equalizer will initially lock onto a post echo, while the
primary signal is sustaining a fade. Having a -40us pre-echo capability allows
the equalizer to successfully handle the primary signal when it returns.
When this unusual condition occurs, you can sustain post-echos up to +80us.
And when the primary signal is detected first, it is centered in the equalizer,
so that -40us pre-echos and +40us post-echos can be tolerated.
[Specmanship, you gotta love the games.....]

Numerous on-air test capture programs have attempted to determine the "worst case"
performance requirements in order to derive the very detailed ATSC A/74 guidelines.
You would need to be in a particularly bad inner city location with tall buildings
reflecting signals to come even close to the above extremes. What is more
important to most users is the performance with short delay (under 1 us)
multipath, such as encounted from nearby buildings and objects (e.g. attic).

The most complete performance characterization that I've seen "recently" (Mar02 test)
was for the LINX prototype that evolved into the latest Micronas Tuner chips:

There are several earliler lab and on-air test reports (e.g. Brazil, Australia), but since they
used 1st and 2nd generation implementations, the performance was severely lacking.
post #323 of 433
First On-Air Test of the First EIA/CEA-909 interface in an STB with the First Smart Antenna.

For the past two weeks, I compared the On-Air DTV performance of the DTA-5000 Smart Antenna
to a 4-Bay Vertical Zig-Zag for two indoor and two outdoor locations chosen primarily for WAF.
The Smart Antenna consistently brought in the more difficult channels when the 4-Bay
required hunting around for the best location and still suffered varying degrees of signal dropout.
I was impressed the presumably low-gain, compact DTA-5000 outperformed a medium gain 4-Bay.

The DTA-5000 is probably best suited for short to medium ranges (under 30 miles),
and especially with difficult multipath conditions, such as indoors and perhaps in
urban concrete canyons (did not test).

See my above posts on 6/30 and 7/15, as well as below attachment for more info.

For the first Sylvania 6900DTE I received from Amazon.com, both the Optical and Coax
Dolby Digital Audio interfaces were not operating correctly. All of the idiot lights on my
Sony Surround Receiver indicated reception of a valid Dolby Digital 5.1 signal, however
no sound was coming out of my speakers except an occasional "click--snap" whenever
the DTV signal went though a signal dropout. The exact same thing occurred when I
tried the Optical and Coax inputs on a Creative Extigy Surround Sound system driving
Quad discrete audio outputs. Well, at least the Stereo L/R outputs work....

The replacement box came a couple days ago from Amazon.com.
Although I was very impressed by their nearly overnight response,
the second 6900DTE suffers from the exact same problem!!!!
Hmmm, "once happenstance, twice coincidence", but Amazon won't swap for a third.....

I checked the Owner's Manual and called the Funai Service Center at 1-800-968-3429.
They did not recognize either the 6900DTE or the Funai STB400E model numbers and
hence could not help me in either troubleshooting or Warranty Service info.

The Owner's Manual also gave the fol. website: www.funai-corp.com
Sure enough, the Sylvania 6900DTE is on the website and I found the phone number
for the Teterboro, NJ Sales HD (201-288-2063) and left my number on the automated
answering system, since it is impossible to talk to a living, breathing, (thinking?) hu-man.

They also had a different number for Funai Corp Service (310-787-3000) in Torrance, CA.
First time through they transferred me to Funai Cust. Service, who again didn't know
about the Sylvania 6900DTE and hence didn't know anything about Warranty Service.
Second time through I asked for "warranty management" and was connected to the
automated answering service for Dan Erickson, who has yet to call me back.
Third time through I asked for Sylvania Sales and was told to contact Nelson Cepeda
at the Teterboro, NJ office (201-727-4529), who has yet to call me back.

The above website also provided a list of authorized Sylvania Repair Centers.
I called the closest and explained to him the lack of info from Torrance Service Center.
He has never heard of the 6900DTE and figured that if the Svc Ctr didn't know about it
then he wouldn't expect that they would cover any warranty repair work.

The next day I called the next closest Repair Center, who checked the on-line Sylvania
Repair Center Only website and found information concerning the warranty coverage
for the 6900DTE, as well as schematics. (JACKPOT!!!)

He also gave me the name and extension (Carlos x233) of the Sylvania Repair POC at
the Torrance facility, who recognized that they provided Warranty Service for the 6900DTE,
but had no information whether there was either a known design defect or available
firmware update.

He connected me to a "Service Center Supervisor" who indicated that the 6900DTE was
indeed listed on his computer system, but he did not know of any known Dolby
Digital hardware design/manufacturing problems or firmware updates.

He then jumped into his "trouble shooting" script and tried to convince me that I had to
disconnect the L/R Audio interface in order for the Optical & Coax DD outputs to work.
I tried it and (of course) it made no difference. I also commented that there was a very
loud "click-snap" noise every time there was a signal dropout, at which time he said that
my problem must be in the antenna. AAARRRRGGGGHHHHH!!!!!!

I tried to explain to him that he wasn't helping to solve the REAL PROBLEM and that
no one would ever design a DD interface that required the L/R audio to be disconnected.
He said that I must know more about these equipments than he did...click buzzzz....

So I guess I'll watch SMALLVILLE tonight and tomorrow and probably decide to drop the
unit off at an authorized Sylvania Warranty Service Center.

The saga continues.....


Funai Tech Support claimed they found and fixed a problem in the Dolby Digital (Optical and Coax) on the Sylvania 6900DTE STB.
But when I connected it to my Sony STR-DE835 Surround Receiver, it had same symptoms as before:
idiot lights display when either PCM STEREO or DOLBY DIGITAL is detected, but no sound is output to speakers.
So back to using L/R Stereo connection...at least until SMALLVILLE goes to reruns.

Recently, I bought a new Surround Receiver (Pioneer VSX-1015TX-K with 100 MHz bandwidth component video switching)
and now the Dolby Digital (Optical/Coax) interface on the Sylvania 6900DTE STB is finally working!!!

So there must be some sort of compatibility problem between the 6900DTE and the STR-DE835.


Sylvania 6900DTE + DTA-5000 On-Air Test.zip 490.7197265625k . file
post #324 of 433
Wow thanks Hol_lands Great informational post. To bad about the digital audio issues. Gee its always something ! It looks like your OTA reception issues are greater then mine. What is the ant CTR socket for? is this hocked up to the antenna along with the RF. Is this needed for the DTA5000 antenna? Thanks for all the help this combo is on my short list.
post #325 of 433
The STB originates DC Power and EIA/CEA-909 Smart Antenna Control information,
which it provides to a DPI-10 Control Box via the ANT CTL jack.
The DPI-10 goes between the coax downlead and the STB's RF input, in order
to insert DC power and antenna control information up the coax to the DTA-5000.
post #326 of 433
Got ya thanks holl_lands
post #327 of 433

Finally found the Test Reports for the Zenith/LG 5th Gen Prototype STB, the LINX (now Micronas) Prototype STB
plus a Field Test Report for the LINX Prototype STB compared to an older Harris ATSC STB (plus some Nokia COFDM STB equalizer tests):

1. Performance of 5th Generation 8-VSB Receivers, Laud, Aitken, Brett and Kwak,
IEEE Trans on Consumer Electronics, Vol 50, No 4, Nov 2004.

2. An ATSC DTV Receiver with Improved Robustness to Multipath and Distributed Transmission Environments,
Wu, Wang, Citta, et. al., IEEE Trans on Broadcasting, Vol 50, No 1, Mar 2004.

3. Results of the Lab Evaluation of Zenith 5th Generation VSB TV Receiver, Communications Research Center (CRC, Canada), Sep 2003.

4. Field Tests of the LINX ATSC Prototype Receiver, Communications Research Center (CRC, Canada), Mar 2003.

5. Recent Performance Improvements to the ATSC Transmission System, Su, Wang, Salehian, et. al.,
Intl Broadcasting Convention (IBC) Conference Pub 2003. See http://www.crc.ca/en/html/crc/home/r...broadcast/rtnt

6. Results of the Lab Evaluation of LINX ATSC Prototype Receiver, Communications Research Center (CRC, Canada), Apr 2002.

IEEE refs are available on-line (for a fee) or from a well-equipped (University) library.
The first IEEE reference had the all important link to CRC reports: http://www.broadcastpapers.com/tvtra...RCATSCTran.pdf

ATSC Doc A/74, Recommended Practice: Receiver Performance Guidelines, Jun 2004
says that a typical channel impulse response ranges from -10 us (pre-echo) to +40 us (post-echo).

A/74 then goes on to provide an Echo Delay performance profile for Single Static Echoes with various Desired to Echo Ratios:

from 0 to +5 us (for D/E > 1 dB) [Note: 0 dB Echo is not stipulated.]
from -5 to +10 us (for D/E > 2 dB)
from -5 to +20 us (for D/E > 3 dB)
from -10 to +40 us (for D/E > 5 dB) [The typical response cited above.]
from -20 to +40 us (for D/E > 7.5 dB) [Suggested Extension]
from -25 to +50 us (for D/E > 16 dB) [Suggested Extension]

So A/74 expects the typical impulse response to have a D/E > 5 dB and the so-called 0 dB Echo
or equal strength signals are expected to have a fairly small delay.
And extremely long pre-echo or post-echo signals would be at a much lower level than the desired signal.
[Indeed, if the echoes are much more than a D/E of 16 dB, they could be expected to cause minimal if any degradation.]

So how well did the Zenith/LG 5th Gen and LINX/Micronas Prototypes perform?
The LINX prototype was better than the LG prototype for all except the last test:

a. Random Noise: LINX C/N was 0.4 to 0.8 dB lower. LG worse at Weak signal levels.

b. Burst Noise: LINX sustained slightly wider pulse widths.

c. Brazil A thru E Test Ensembles: LINX C/N was a few tenths to several dB better.

d. Strong Static Echoes: LINX C/N was much lower for ACATS #286 and
Modified Brazil C/D test profiles.

e. Single Dynamic Echoes with increasing Doppler Rates: LG was better for two test
conditions, but failed for another two. LINX was better for four test profiles
and did not fail any.

f. Susceptibility to Dynamic Echoes in Presence of Random Noise: As expected,
LINX failed the CRC #3 and #4 profiles due to 35 us Echo exceeding equalizer
capability. However, for CRC #1 and #2, the LINX could tolerate D/E
approaching 0 dB, whereas the LG could not.

g. Single Echo Affecting Pilot: LINX passed. LG could not handle without errors.

h. Single Echo Test (parens denote whether it meets A/74 Guidelines or not).
Note that while the LG prototype was significantly better than the LINX prototype,
NEITHER unit met all of the A/74 Guidelines during this last test:

D/E = 10 dB -48.5 to +49.5 us for LG (yes) and -29.5 to +38.5 us for LINX (close)
D/E = 6 dB -24.0 to +25.5 us for LG (no) and -9.0 to +28.5 us for LINX (no)
D/E = 3 dB -13.0 to +13.0 us for LG (no) and -11.0 to +12.0 us for LINX (no)
D/E = 0 dB LG: not working and LINX: no test entry

Other performance Guidelines from A74:

i. Sensitivity: -83 dBm [Hence Noise Figure ~ 7 to 8 dB.]
Zenith/LG was -78.4 dBm, which does not meet A/74 Guidelines.
LINX not tested.

j. Max Input: -8 dBm (for each of multiple input signals)
Zenith/LG was -2.3 dBm for single input, multiple inputs not tested.
LINX not tested.

k. DTV Co-Channel D/U (at -68 and -53 dBm): +15.5 dB
Not tested. [LG may have problems meeting this test, see results for a. above.]

l. NTSC Co-Channel D/U (at -68 and -53 dBm): +2.5 dB
Zenith/LG was +3.1 dBm, which does not meet A/74 Guidelines.
LINX was +3.9 dBm, which does not meet A/74 Guidelines.

m. NTSC Adj-Chan D/U: -40 dB (at -68dBm), -35 dB (at -53 dBm), and -26 dBm (at -28 dBm)
Zenith/LG was -41.8 (at -68 dBm) and -42.0 dBm (at -53 dBm), meets A/74.
LINX was -43.7 (at -68 dBm) and -39.9 dBm (at -53 dBm), meets A/74.

n. DTV Adj-Chan D/U: -33 dB (at -68dBm), -33 dB (at -53 dBm), and -20 dBm (at -28 dBm)
Not tested.

Based on these tests, if you don't need extremely long pre and post-echo performance,
the LINX/Micronas prototype clearly had better overall performance.
And when Zenith/LG claims +/- 50 us equalizer capability,
they must mean when the Echo is 10 dB or more below the Desired signal.
Note they avoided mentioning performance for A/74 stipulated typical condition (D/E = 5 dB),
because both units failed to meet that guideline.

So it is impossible to compare manufacturer equalizer "claims" unless they also stipulate the test conditions!!!!

Of course, performance for production units may be different.
post #328 of 433
Thread Starter 
Thanks for the informative post.

So where can we buy the LINX/Micronas in a stand alone OTA receiver?

post #329 of 433

Pop the cover off and let us know what Tuner Model number you find.
Opening the Tuner itself is highly discouraged, but you might see the part number
of the big ATSC Decoder chip on the main board or poking through the Tuner's view window....

See attached for a summary of what I've found after many hours of web surfing various
ATSC Tuner manufacturer websites, including a summary for ATSC PCI cards and the
beginnings of a summary for ATSC OTA STBs.

I read that LINX also licensed their technology to ST Microelectronics.
But I don't yet know what U.S. STBs use STMicroelectronics or Micronas
(they are apparently concentrating on DVB-T).
It isn't very easy to determine what's inside without actually opening it and looking.

So if you have the skills, pull out a screwdriver and give it a twist....


ATSC_NTSC Tuner Specs.zip 8.3935546875k . file
post #330 of 433
It seems somewhat illogical for the manufacturers to emphasize the MAXIMUM
equalizer capability for Desired to Echo (D/E) ratios of 10 dB or more.
ATSC A/74 Receiver Guidelines consider D/E ratios above 7.5 dB as being
a "Suggested Extension" to performance, no doubt based on measured statistics
that show extremely long pre- and post-echoes to be extremely rare.

Even more illogical is to overlook the performance for the large number of known test locations
where worst case pre- and post-echoes were found to be within -10 to +40 us with D/E less than 7.5 dB.

With that in mind, here are some more Maximum Static Echo test results:

Some Static Echo test results were found in CRC's "Field Test Report of the LINX ATSC Prototype Receiver"
(ref 4 above). Unfortunately, this is the only lab test included in the Field Test Report.
The test included an updated LINX Prototype (a year later than the preceeding report),
an earlier Harris ATSC Receiver (model number unknown)
and a Nokia DVB-T (COFDM) Receiver (model number unknown).

Single Echo Test Results (parens denote whether it meets A/74 Guidelines or not),
presented in chronological order (including preceeding test results).

LINX Prototype #1 (Apr 2002):
D/E = 10 dB, -29.5 to +38.5 us (close)
D/E = 6 dB, -9.0 to +28.5 us (no)
D/E = 3 dB, -11.0 to +12.0 us (no)
D/E = 0 dB, no test entry

LINX Prototype #2 (Mar 2003):
D/E = 10 dB, -35 to +38 us (close)
D/E = 6 dB, Not tested
D/E = 3 dB, -8.5 to +38.5 us (yes)
D/E = 0 dB, -17 to +17 us (yes)

HARRIS (2nd or 3rd Gen?) (Mar 2003):
D/E = 10 dB, -5 to +40 us (close)
D/E = 6 dB, Not tested
D/E = 3 dB, -1 to +36 us (no)
D/E = 0 dB, Not working

Zenith/LG 5th Gen Prototype (Sep 2003):
D/E = 10 dB, -48.5 to +49.5 us (yes)
D/E = 6 dB, -24.0 to +25.5 us (no)
D/E = 3 dB, -13.0 to +13.0 us (no)
D/E = 0 dB, Not working

Note that the LG prototype had a higher MAXIMUM equalizer capability (- 48.5 and +49.5 us)
when the Echo power was sufficiently weak (D/E = 10 dB).
The updated LINX prototype had nearly as much MAXIMUM equalizer capability (+35 and - 38 us)
and was the ONLY unit tested that met the A/74 Guidelines for the
much more frequently encountered Static Echo conditions with D/E < 7.5 dB.

Note that NONE of the units met all of the A/74 Guidelines during these tests.
Of course, production units may have different results.....

Almost forgot: Nokia DVB-T COFDM blew them all out of the water on this test.
It could sustain D/E between 0 and 1 dB at up to +/-74 us pre/post echo delays.
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