Say Eric;
In regards to Telecommunications Industry Association do they have a web
site ?
Thanks
MH
----- Original Message -----
From: "Eric Lemmon" <[EMAIL PROTECTED]>
To: <Repeater-Builder@yahoogroups.com>
Sent: Thursday, September 09, 2004 9:14 PM
Subject: [Repeater-Builder] CTCSS Decoder Response Times - General
Information
> Several recent postings have mentioned that the speed of response to a
> carrier with a CTCSS ("PL") tone is faster with higher tones. It
> happens that there is an international standard, TIA-603-B-2002, which
> describes this and many other facets of commercial radio systems. The
> Telecommunications Industry Association standard is entitled, "Land
> Mobile FM or PM Communications Equipment, Measurement and Performance
> Standards." The great majority of reputable radio manufacturers certify
> that their products meet this standard.
>
> Paragraph 3.4.2.2 states that "The maximum attack time for CTCSS
> modulation shall be 250 ms except for frequencies below 100 Hz. Below
> 100 Hz, the time shall be computed by the following formula:" The
> formula is 25,000 divided by the CTCSS frequency in Hz; the answer is in
> milliseconds (ms). Given a low-end CTCSS tone of 67.0 Hz, a radio must
> respond within 373 ms. That's a long time! However, as several posters
> have noted, careful filtering of low-frequency noise and/or elimination
> of DC offsets can significantly reduce the response time.
>
> The same standard also specifies that CDCSS ("DPL") codes must be
> decoded within 350 ms. System operators who are considering using
> digital codes should be aware of this longer decode time.
>
> 73, Eric Lemmon WB6FLY
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/Repeater-Builder/
<*> To unsubscribe from this group, send an email to:
[EMAIL PROTECTED]
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
