Crystal characterization and
filter design
This
page is a place to put my notes and a few documents from a presentation
I gave at the OzarkCon QRP convention in Joplin, Missouri in 2008.
My slide show was really too big (over 4 MB) in native
PowerPoint, but I converted it into a PDF and made it much smaller.
Same for a Word document that covered the same stuff in greater
detail.
It feels incomplete, but you should have seen me trying
to cover all this ground in 50 minutes. I think the crystal
measurements topic is covered pretty well, but the filter design part
is mainly a discussion and overview of available software design tools.
The following links are to my presentation's slide show and an
accompanying text document.
Slide show PDF
Document PDF
I
was lucky to find (or be found by) Darell Brehm, WA3OPY of
International Crystals (ICM), who introduced me to Bill Carver W7AAZ,
noted ham technical guru and author of a number of articles.
Darell took four crystals I had measured with my homebrewed
circuits and did his own measurements with ICM's professional
equipment, then sent them to Bill who did them on his vector analyzer.
So I had two good "controls" for my crystals and I compare the
results with my own measurements in the slide show.
The links
below are to a couple of documents Mr. Carver was kind enough to
provide me. First are his notes from a crystal filter
presentation he did, I think at Dayton. Next is a sketched out
circuit he recommended to me for crystal measurements using the Hycas
amplifier I mentioned having built Note that his fixture puts the
crystal in a one ohm (!) environment, necessitating a lot of gain --
use for the Hycas.
Carver lecture notes PDF
Carver crystal test
circuit and notes PDF
Back to my ham
page