[TenTec] Re: TenTec Amateur Radio Digest V4 #145

Richard B Drake rich@w3zj.com
Thu, 17 May 2001 13:05:46 -0400


Even the worlds largest super computers can not to floating point
arithmetic 100% accurately. This is because it is physically
impossible to represent fractional values 100% accurately in
binary. The more bits that are used in the process, the more
accurate it becomes but complex calculations have to be planned
out very carefully to minimize the error and in the end there is
always some rounding required. When you are talking about needing
accuracy in area of fractional parts per million (10 Hz out of
30MHz) a 32 or even 64 bit floating point processor is in over its
head.

----
73, Rich - W3ZJ

> -----Original Message-----
> From: owner-tentec@contesting.com
> [mailto:owner-tentec@contesting.com]On
> Behalf Of Carl Hyde
> Sent: Thursday, May 17, 2001 10:59 AM
> To: W B Reese; tentec@contesting.com
> Subject: Re: [TenTec] Re: TenTec Amateur Radio Digest V4 #145
>
>
>
> The drifting Mark is seeing in Digipan is due more to
> the software and the
> computers Real Time Clock that to the Omni V's drift.
> Remember PC Processors
> don't do floating point math very well.
>
> TT sets the offset to 600 Hz so just tune 600 away from
> the point where the
> other guys cw tone dissapears.
>
> Hell we've been sending and receiving CW with drifty
> old tube radios with no
> crystals since ham radio began. How accurate does it
> have to be? Not as
> accurate as it is.
>
>
> __________________________________________________
> Do You Yahoo!?
> Yahoo! Auctions - buy the things you want at great prices
> http://auctions.yahoo.com/
>
> --
> FAQ on WWW:               http://www.contesting.com/FAQ/tentec
> Submissions:              tentec@contesting.com
> Administrative requests:  tentec-REQUEST@contesting.com
> Problems:                 owner-tentec@contesting.com
>
>


--
FAQ on WWW:               http://www.contesting.com/FAQ/tentec
Submissions:              tentec@contesting.com
Administrative requests:  tentec-REQUEST@contesting.com
Problems:                 owner-tentec@contesting.com