Archive of the former Yahoo!Groups mailing list: MOTM

1.) The DVCO is a good idea in the freq shifter if it tracks
1v/oct. It is my understanding that to do frequency shifting you
need a quadrature oscillator and a filter that also does much the
same thing (quadrature filter?) That is you need four sine
waveforms (if you are using a sine) which are each offset 90 degrees
from each other. This is difficult to design into an analog
oscillator especially over a very big range and you definitely want
to be able to generate a very low frequency for subtle shifting
like .5 HZ or lower. You could scan a wavetable with a sawtooth
like the MiniWave to generate the four sines using a VCO like
Paul's. The filter is much trickier since it you are trying to
shift phase equally across the entire frequency range unlike a so
called phase shifter which is really more of a time delay filter.
The multiplier part is simple by comparison.

2.) I have a set of Greenlee punches which go up to about 3" in
diameter. .125 aluminum is no problem. I'm not sure I'd punch
steel that thick, but they do a pretty good job on steel as well.
They do take a lot of pressure but using the screw and ratchet that
came with the punches they do the job. A 1" hole is cake. Where it
gets tricky is with odd sized holes. I usually use the next smaller
punch and then enlarge the hole on a milling machine. (not CNC) If
the part to be mounted has a flange I usually just eyeball it,
otherwise setup is a pain. But the Greenlee punches are great. If
I was going to mass produce I'd make a die with removable punches
specifically for panels the size of the MOTMs. The punches could be
added or left out depending on the panel configuration. I'd use a
punch press and feed them one at a time.

3.) I'm very happy to have the schematics for the MOTM and Blacet
modules. However, I can understand the reasons for witholding them
as well. There are some companies which specialize in reverse
engineering and making knockoffs of everything. A company starting
with a B comes to mind. Patents do not help. If you file for a
patent you are telling your competition how you make your product.
Then they either figure out a product just different enough to get
outside the patent or the Chinese make it (they routinely ignore
patent and copyright law.) Patents, Copyrights and Trademarks are no
protection in an international market. If you are small enough you
will be ignored, but as the Chinese try to grab more and more of the
world market they are focusing in on smaller and smaller niches.
Other countries play this game as well, but the Chinese are the
biggest offenders. Beware!!! I have had experience in this and
know what I'm talking about.