Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.arch.embedded > #25113

Re: Optimize pow() function

From Chris <xxx.syseng.yyy@gfsys.co.uk>
Newsgroups comp.arch.embedded
Subject Re: Optimize pow() function
Date 2016-09-26 17:30 +0000
Organization Aioe.org NNTP Server
Message-ID <nsbluq$1jp5$1@gioia.aioe.org> (permalink)
References <ns0mo1$7j2$1@dont-email.me> <DZNFz.52445$ba.36815@fx25.iad> <ns8jte$kn4$1@dont-email.me>

Show all headers | View raw

On 09/25/16 13:36, Tauno Voipio wrote:

>
> The situation of the OP is more complex: He's attempting to measure
> the output power of a RF amplifier by measuring the DC feed voltage
> and relating the output power to it.
>
> There are simply too many moving parts in the equation, it will not
> work with some mathematical trickery.
>

This has been a long thread, but fundamentally, you can't determine
output power into the load without measuring the load vswr. Depending
on the output power, a simple directional coupler could be a short 
length of coax, measuring forward and reverse power simultaaneously,
which could be calibrated via a lookup table and interpolation to the
required accuracy. No need for complex math in the software...

Why does it have to be such hard work ?...

Regards,

Chris

Back to comp.arch.embedded | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Optimize pow() function pozz <pozzugno@gmail.com> - 2016-09-22 15:36 +0200
  Re: Optimize pow() function Don Y <blockedofcourse@foo.invalid> - 2016-09-22 07:17 -0700
    Re: Optimize pow() function pozz <pozzugno@gmail.com> - 2016-09-22 23:10 +0200
      Re: Optimize pow() function rickman <gnuarm@gmail.com> - 2016-09-22 17:31 -0400
        Re: Optimize pow() function lasselangwadtchristensen@gmail.com - 2016-09-22 14:44 -0700
        Re: Optimize pow() function pozz <pozzugno@gmail.com> - 2016-09-23 09:03 +0200
          Re: Optimize pow() function Paul Rubin <no.email@nospam.invalid> - 2016-09-23 00:17 -0700
          Re: Optimize pow() function Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2016-09-23 22:45 +0300
      Re: Optimize pow() function rickman <gnuarm@gmail.com> - 2016-09-22 17:44 -0400
        Re: Optimize pow() function pozz <pozzugno@gmail.com> - 2016-09-23 09:08 +0200
          Re: Optimize pow() function rickman <gnuarm@gmail.com> - 2016-09-24 01:54 -0400
      Re: Optimize pow() function Don Y <blockedofcourse@foo.invalid> - 2016-09-22 14:50 -0700
        Re: Optimize pow() function pozz <pozzugno@gmail.com> - 2016-09-23 09:23 +0200
          Re: Optimize pow() function Don Y <blockedofcourse@foo.invalid> - 2016-09-23 00:32 -0700
          Re: Optimize pow() function Evgeny Filatov <e.v.filatov@ieee.org> - 2016-09-23 12:56 +0300
            Re: Optimize pow() function Don Y <blockedofcourse@foo.invalid> - 2016-09-23 10:41 -0700
          Re: Optimize pow() function Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2016-09-23 21:07 +0200
          Re: Optimize pow() function Don Y <blockedofcourse@foo.invalid> - 2016-09-23 12:12 -0700
    Re: Optimize pow() function pozz <pozzugno@gmail.com> - 2016-09-22 23:12 +0200
      Re: Optimize pow() function Don Y <blockedofcourse@foo.invalid> - 2016-09-22 14:58 -0700
  Re: Optimize pow() function Tim Wescott <tim@seemywebsite.com> - 2016-09-22 10:01 -0500
    Re: Optimize pow() function Jack <jack4747@gmail.com> - 2016-09-22 08:08 -0700
      Re: Optimize pow() function Tim Wescott <seemywebsite@myfooter.really> - 2016-09-22 11:53 -0500
        Re: Optimize pow() function pippo2@disney.com (Jack) - 2016-09-22 21:12 +0200
          Re: Optimize pow() function lasselangwadtchristensen@gmail.com - 2016-09-22 13:12 -0700
          Re: Optimize pow() function Tim Wescott <seemywebsite@myfooter.really> - 2016-09-22 15:51 -0500
    Re: Optimize pow() function pozz <pozzugno@gmail.com> - 2016-09-22 23:15 +0200
      Re: Optimize pow() function Tim Wescott <seemywebsite@myfooter.really> - 2016-09-22 17:52 -0500
      Re: Optimize pow() function David Brown <david.brown@hesbynett.no> - 2016-09-23 09:32 +0200
    Re: Optimize pow() function David Brown <david.brown@hesbynett.no> - 2016-09-23 09:28 +0200
      Re: Optimize pow() function Paul Rubin <no.email@nospam.invalid> - 2016-09-23 00:47 -0700
        Re: Optimize pow() function David Brown <david.brown@hesbynett.no> - 2016-09-23 11:05 +0200
        Re: Optimize pow() function Tim Wescott <tim@seemywebsite.com> - 2016-09-23 11:44 -0500
  Re: Optimize pow() function Jack <jack4747@gmail.com> - 2016-09-22 23:15 -0700
    Re: Optimize pow() function Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2016-09-23 20:49 +0200
  Re: Optimize pow() function Richard Damon <Richard@Damon-Family.org> - 2016-09-25 06:50 -0400
    Re: Optimize pow() function Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2016-09-25 16:36 +0300
      Re: Optimize pow() function Chris <xxx.syseng.yyy@gfsys.co.uk> - 2016-09-26 17:30 +0000
        Re: Optimize pow() function Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2016-09-26 21:49 +0300
      Re: Optimize pow() function pozz <pozzugno@gmail.com> - 2016-09-26 23:30 +0200
        Re: Optimize pow() function Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2016-09-27 18:58 +0300
  Re: Optimize pow() function Robert Wessel <robertwessel2@yahoo.com> - 2016-09-26 22:44 -0500

csiph-web