Re: XG3 and IMD testing

Posted by Jack Smith-6 on Apr 16, 2011; 1:55pm
URL: http://elecraft.85.s1.nabble.com/XG3-device-tp6271930p6278971.html

A  classic comb generator products equal level harmonics.

In the time domain, it is an impulse waveform--in the limit infinitely
narrow. It can be approximated by differentiating a fast rise/fall
square wave with an RC circuit.

If you search "comb generator" you can find many implementations on the
Internet.

Jack K8ZOA


On 4/16/2011 8:15 AM, David Cutter wrote:

> For my education: what is the mark-space ratio to develop optimum even and
> odd harmonics?  Does this have any merit?
>
> David
> G3UNA
>
>
>> And by the way, the XG1 and XG2 also have more or less square-wave
>> output. This is where the harmonics come from that allow them to put
>> out a useful signal on higher bands.
>>
>> For the intended applications, this waveform is not an issue, because
>> the receiver under test will virtually always have a low-pass filter
>> at its antenna input.
>>
>> 73,
>> Wayne
>> N6KR
>>
>>
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