DTV Converter Boxes and Signal Strength [Text View]

northbear

04-08-08, 05:38 PM

Quick question because I can't seem to find a clear answer:

Do most/all of the DTV converter boxes have on-screen signal strength indicators?

I haven't gotten an HDTV yet, and I'm in the process of setting up my DIY antenna in the attic. I want to optimize the direction of the antenna as much as possible, and I was hoping that the DTV converter boxes would have signal strength indicators similiar to those on most HDTVs.

Does anyone know which current DTV converter boxes do/don't have such indicators?

All CECB are required to have a signal strength indicator

"To further assist consumers in improving signal reception, we include in the Final Rule provisions that require manufacturers to include software which will display on the television receiver signal strength and permit the display of other operating parameters chosen by the manufacturer."

Source:
http://www.ntia.doc.gov/ntiahome/frnotices/2007/DTVFinalRule_2e.htm
Item #94

You probably already know about antennaweb.org (http://antennaweb.org/) and tvfool.com (http://tvfool.com/) which can help with aligning antennas, but I will mention it anyways just in case :)

Nitewatchman

04-08-08, 09:55 PM

Here in this document from NTIA :

TECHNICAL APPENDIX 1, NTIA Coupon-Eligible Converter Box (CECB), Required Minimum Performance Specifications and Features (http://www.ntia.doc.gov/ntiahome/frnotices/2007/DTVFinalRule_technical.htm)

#24 says :

"24. Signal Quality Indicator

"The equipment will display on the television receiver signal quality indications such as signal strength per ATSC A/74, Section 4.7. "

Note it says "such as signal strength", not "required signal strength" ...

---------------------------

ATSC doc. A74 "ATSC Recommended Practice: Receiver Performance Guidelines (with Corrigendum No. 1 and Amendment No. 1)", Section 4.7 Says : (http://www.atsc.org/standards/a_74-w-Corr-1-Amend-1.pdf )

4.7 Consumer Interface—Received Signal Quality Indicator
The capability to display received signal quality conditions on a quasi-real time basis is a feature that should be included in all digital broadcast receivers.
Unlike analog reception, transmission impairments such as echo, interference and noise do not manifest themselves in uniquely identifiable ways in a digital broadcast receiver’s display. Reception and display of digital signals on a digital receiver is largely a “go-no go” experience for the consumer, and the received picture or audio by themselves offer little useful guidance as to the relative difficulty of the current reception conditions.
A digital broadcast receiver’s digital signal quality indicator should be more than simply a signal strength meter, and should take into account the effects of multipath and interference impairments, as well as insufficient or excessive signal level. Moreover, the signal indicator should be easy to understand, intuitive to use and easy to access for a consumer in order to effectively position or aim an antenna, judge the need or effectiveness of additional front end amplification and/or aid in other user-controlled adjustments to optimize the receiver’s configuration with respect to the current reception conditions.
Receiver manufacturers should consider two applications of indicator displays; setup displays and operational displays. Each application should provide some manner of signal level indication as well as indications of the effects of multipath and interference impairments. Setup displays should be persistent to facilitate the installer’s achieving proper system alignment. Operational displays may be transient or under user control if desired. User options should be provided in both categories.
Means to achieve such signal quality indications should be left to the judgment of individual receiver manufacturers.

A74 basically says a "signal strength" meter is not enough, and goes on to specify/recommend all the stuff we'd love to have as signal diagnostic tools on our receivers, but then says "Means to acheive such signal quality indications shuld be left to the judgment of individual receiver manufactuers" ...

Well, OK, for the most part that's what the NTIA info says as well ... but what about the info northbear quoted which says :

"We include in the Final Rule provisions that require manufacturers to include software which will display on the television receiver signal strength and permit the display of other operating parameters chosen by the manufacturer. " ...

Gee, that seems like it's saying they are requiring signal strength meters, regardless of what other sort of meter is provided ... Did they revise/change/amend that or something, or did the rule as used by the manufacturers get "shortened" and summarized so that it lost the "signal strength" meaning ?

In any case, I suspect the "signal meters" on many, if not most DTV receivers, including CECB's such as my ZenithDTT900's, and including in some cases on DTV receivers when they are erronously labeled "signal strength" meters right on screen(such as the "bar" reading on my Sony KD34XBR960's "signal diagnostic" screen), may be implemented along the lines (if not exactly like this) as discussed in a Document that used to be available at either ATSC or ATSCforum site (but I couldn't find it there last time I looked, I did dig it up off a CD here though), entitled : " Preliminary DTV Field Test Results And Their Effects on VSB Receiver Design" Gary Sgrignoli Zenith Electronics Corporation - 8/20/99 --

As follows (the last part being of most interest) :

....."The MPEG data sync is reinserted at the receiver output for subsequent processing in the receiver’s MPEG transport decoder. The one-segment long binary frame sync not only provides pseudo-random number sequences (PN) for data frame synchronization, but can also be used as a training signal for the receiver’s equalizer and as a means to measure received signal quality."