From: email@example.com (Glen Walpert)
Subject: Re: Comb/Harmonic Generators
X-Newsreader: News Xpress 2.01
Date: Mon, 09 Dec 2002 13:48:25 GMT
NNTP-Posting-Date: Mon, 09 Dec 2002 08:48:25 EST
Organization: Net Access (netaxs.com)
In article , "Bill Sloman" wrote:
>"John Larkin" wrote in
>> On Thu, 05 Dec 2002 20:01:31 GMT, firstname.lastname@example.org (Glen Walpert)
>> >There is a diode built into these transmission lines, and apparently the
>> >effective dielectric constant of the transmission changes with the bias
>> >diodes? Perhaps Vance could tell us something about these?
>> right. You can google 'nonlinear transmission line' or 'shock line'. A
>> diode-loaded transmission line can propagate a wave that gets steeper
>> as it travels, essentially a soliton. It's also been done with
>> nonlinear ceramic capacitors, but not nearly as fast.
Thanks, I found a lot of interesting info on this effect, which I had never
previously even heard of.
>I've got a Russian paper (in English - my Russian was never up to much)
>lying around at home which describes a non-linear transmission line
>compresor based on ferrites operating near saturation. It was a present from
>a very clever friend of mine, who seemed to understand it.
Ah yes, propogation velocity in a transmission line is as much a function of
inductance per unit length as it is of capacitance per unit length, so any
nonlinearity in inductance must cause a change in pulse shape also; the
reduction in inductance due to saturation will cause an increase in
propogation velocity and leading edge compression for a pulse which increases
the DC bias current, or trailing edge compression for the opposite polarity.
If you can easily find the title of the paper you referred to I would be
interested in seeing if I can find a copy.
As far as uses for the resulting comb/harmonic generator, perhaps it could be
useful for EMI succeptability testing - greatly reducing the requirement for
signal generator frequency range, and allowing a slow sweep to cover a very
wide frequency range in a relatively short period of time?