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Re: [Amps] Checking for IMD

To: Tony King - W4ZT <amps080906@w4zt.com>
Subject: Re: [Amps] Checking for IMD
From: R L Measures <r@somis.org>
Date: Sun, 13 Aug 2006 03:38:57 -0700
List-post: <mailto:amps@contesting.com>
On Aug 12, 2006, at 8:20 PM, Tony King - W4ZT wrote:

> Tom W8JI wrote:
>>> thread. I summarized some of their comments and included a method
>>> that Rich suggested for measuring AVERAGE IMD with another receiver
>>> and a calibrated step attenuator at <http://gs35b.com/imd.html>. Of
>>> course this method can't be used to quote specific numbers for the
>>> 3rd and 5th order products but produces an overall look at your
>>> system performance.
>
>>
>> I'm pretty sure that does not give you the average IM level Tony.
>>
>> I'll have to think about that a little bit more, but off the top it
>> seems wrong because the meter on our receivers detects peaks, not
>> average. I'm pretty sure it actually would measure the highest value
>>  of peak power contained in the bandwidth of the receiver filter,
>> assuming the receiver is perfect.
>>
>> Average makes no sense to me, since a receiver S meter is not an
>> averaging measurement device.
>
> That makes sense and it really isn't an issue of peak versus  
> average to
> me but rather a means to compare the levels

Indeed, Tony, indeed.
>>
> ...

R L MEASURES, AG6K. 805-386-3734
r@somis.org



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