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Subject: Re: Frequency Shifter (improved layout idea)

From: "strohs56k" <strohs@...>
Date: 2003-11-05

--- In motm@yahoogroups.com, "Tony Karavidas" <tony@e...> wrote:
>
> This was truly one of the most constructive emails I've read all
> night. Seth, in a way of voicing his opinion about the current
> layout, offered a nice alternative.

I put a little more thought into this and I think I have some
improvements.

Here is the tweaked drawing:

http://www.eskimo.com/~strohs/FSlayout3.GIF

http://www.eskimo.com/~strohs/FSlayout3grid.GIF


The second drawing (with grid in the name) shows the design on top of
the "standard" MOTM grid lines.

As you can see, this design actually fits pretty well on the MOTM
grid. The big frequency knob is centered between what would be the
upper four knob positions on the MOTM grid. And for the small knobs,
the lowest row matches up vertically with the lowest row of knobs on
the MOTM grid. The jack field is exactly on the grid.


What I changed:

Put the input jacks (signal and CV) in a group at the left and the
outputs (local oscillator and shifted signals) in a group at the
right. I think this is the normal left to right signal flow
convention.

I moved the fine shift knob to the right of the big shift knob. This
better matches the convention of oscillators with the coarse tune on
the left / fine tune on the right.

I moved the gain knob to the left of the big shift knob. I think this
better matches the left to right signal flow.

The CV shift knob has therefor moved below the big shift knob. I
think this has good association.

The sine and cosine amplitude knobs (for the local oscillator outputs)
are now on the left side. (This matches up with the local oscillator
outputs in the jack field.)

The up and down feedback knobs are now on the right side. (Again,
matches up with the frequency shifted signal outputs in the jack
field.)

I moved all of the LEDs to the left side of the panel to match the new
positions of their associated knobs.


This version has a little less symmetry than my first stab but is much
more logical in terms of signal flow and grouping of like
functionality.

Also, this might make things a little easier for Tony because there is
a lot more space opened up between the lower set of knobs for
components hidden behind the panel. Also, this is actually a little
closer to his proposed design as far as knob grouping.


Questions for Tony / I think some of these may have been asked and
discussed previously but just in case...

Because the design is "thru zero" - I assume a positive CV makes the
up output up shifted (and down output down shifted) where as a
negative CV makes the up output down shifted (and down output up
shifted)

If so, should the main shift knob be "bipolar" - no shift at center,
negative CV to the left, positive CV to the right? (Should the fine
shift knob also be a "bipolar" control with 0 at center?)

Further, should the "freq CV" knob be a reversing attenuator? (Zero
at center.)

Can we have two more local oscillator outputs for inverse sine and
inverse cosine?


seth


PS: yes, there was a FSlayout2.GIF but just as I was about to upload
the drawing I decided I didn't really like it, pushed some stuff
around again, and it became version 3 :)