MOTM

lissajous patterns...I have a copy of Don Lancaster's Active Filter Cookbook and in it he describes "Quadrature Art".  I tried it with my MOTM-420 filters, one set to High Pass and the other to Low Pass.  Connected one to the vertical amp and the other to the horizontal amp.  Using an oscillator or 2 and fiddling with the resonance can produce some pretty spectacular results.

D. Abbey




________________________________
From: Dave Manley <david_l_manley@...>
To: motm@yahoogroups.com; jneilnyc <jneil@...>
Sent: Thursday, January 29, 2009 12:44:19 PM
Subject: Re: [motm] Re: Scope question


The extra pins on a tek scope probe  typically indicate to the 
scope what type of probe is attached, specifically the
attenuation of the probe (usually x1 or x10).  This allows the 
on screen display of voltage levels (assuming your scope 
supports that) to be scaled appropriately.  So when you measure
a 5V signal with your x10 probe, the scope displays it as
5V and not 0.5V.

All you need (as others have mentioned) is a BNC cable with
an appropriate plug on the end.  Go buy a 6' to 12' BNC to BNC
cable, and then cut it in half.  Put 1/4 plugs on the cut ends
and you have two cables to hook up your scope and make
lissajous patterns...


--- On Wed, 1/28/09, jneilnyc <jneil@jneil. com> wrote:

From: jneilnyc <jneil@jneil. com>
Subject: [motm] Re: Scope question
To: motm@yahoogroups. com
Date: Wednesday, January 28, 2009, 9:50 PM



I was hoping it was as simple as this!  But seeing all the funky
looking probes out there with all the odd connectors and built-in
electronics I just assumed that I was being naive thinking I could
just make a cable.

The Tektronics probes that came with my scope have BNC connectors with
additional contact pins coming out of them - I take it these aren't
necessary in a homebrew cable?

--- In motm@yahoogroups. com, David Abbey <abbeysynth@ ...> wrote:
>
> Beg, borrow, make or buy yourself a coaxial cable with a BNC
connector on at least one end.  Solder a 1/4" phone plug to the other
end (tip to center conductor and sleeve to the braid, but be careful
not to over heat the braid and melt the dielectric).  You can break
out a signal with a multiple by routing your signal into one jack,
taking it out of another in that multiple and plugging your 'scope
cable into a third.  I made 2 for my 'scope (A and B channels).  I
also made one with bananna plugs on one end to use with my DMM.
> 
> 
> 
> 
> ____________ _________ _________ __
> From: jneilnyc <jneil@...>
> To: motm@yahoogroups. com
> Sent: Wednesday, January 28, 2009 8:24:37 PM
> Subject: [motm] Scope question
> 
> 
> 
> I finally sat down tonight at got my Tektronix to give me some
> waveform views of one of my oscillators.  There was more than a little
> trial-and-error at first, but once I got in the ballpark I was able to
> zero in on clear, static waveforms that changed shape in predictable
> and expected ways, which was immensely satisfying (and will no doubt
> impress my musical buddies, for whom a MOTM cabinet is already like
> seeing something out of Close Encounters - this now adds that last mad
> scientist touch). 
> 
> And I got the onboard frequency counter working, which is a nice plus.
> 
> All this was done using a rather painful method whereby I clipped the
> ground to one exposed terminal on the end of a phone cable and touched
> the probe to the other.  While this worked, it was not at all easy to
> do one-handed, and clearly not a long-term methodology.  What I really
> want is to make this kind of connection permanent, ie just have some
> sort of probe terminating in a phone plug that I can tap into any jack
> without worrying about fiddly connections.  Does such a thing exist,
> either ready-to-use or in some combination of probes+adaptors? 
> 
> What do people who know what they're doing do?  (he said, and not for
> the first time...)
> 
> Thanks!
> JN
>