um, it's a semantic thing that i just wrote about in response to Urs. i
don't use the term myself, but i am defining nodal analysis the way i see
virtually all other lit doing it. when spice is modeling non-linear
circuits, it is using Kirchoff's current law on every node, Kirchoff's
Usually all analog can be generalized and approxmiated with the
simplest means.
These designs are usually simple to begin with, as less components,
meant more profit.
Sometimes far below audio-grade components were used, for instance in
monophonic synths, or feedback paths or similar.
On
Dear Robert,
On 22.06.2014, at 04:19, robert bristow-johnson r...@audioimagination.com
wrote:
it's possible that this is only a semantic issue.
Thanks for clearing this up. It's indeed a semantic issue (use of the term
nodal analysis), which then leads to further misunderstandings.
What we
And once more, still: taking a bunch of difference equations (and some
of those were built up in a respectable way, not as a random opportunist
algorithm), and taking their behavior to be exactly the same as a
sampled analog system requires a little rethinking on behalf of a lot of
people
On 22.06.2014, at 19:04, robert bristow-johnson r...@audioimagination.com
wrote:
i don't think i agree with the following claim, Urs,
... but no matter what method of integration we use, we always end up with
the same set of equations to solve for the actual step.
different methods of
On 6/22/14 1:20 PM, Urs Heckmann wrote:
On 22.06.2014, at 19:04, robert bristow-johnsonr...@audioimagination.com
wrote:
2. Get the computer to crunch numbers by iteratively predicting, evaluating and
refining values using the actual non-linear equations until a solution is found.
perhaps
On 22.06.2014, at 20:24, robert bristow-johnson r...@audioimagination.com
wrote:
On 6/22/14 1:20 PM, Urs Heckmann wrote:
On 22.06.2014, at 19:04, robert bristow-johnsonr...@audioimagination.com
wrote:
2. Get the computer to crunch numbers by iteratively predicting,
evaluating and
On 6/22/14 6:01 PM, Urs Heckmann wrote:
On 22.06.2014, at 20:24, robert bristow-johnsonr...@audioimagination.com
wrote:
On 6/22/14 1:20 PM, Urs Heckmann wrote:
On 22.06.2014, at 19:04, robert bristow-johnsonr...@audioimagination.com
wrote:
2. Get the computer to crunch numbers by
It is different for a circuit that isn't a 1 pole RC.
no, it's whenever an integrator (1/s in the s universe) is implemented
numerically with the trapezoid rule. doesn't matter whether it's a C or
anything else.
RBJ: please show me the derivation for a 2 pole Sallen Key using the
bi-linear
I think the important thing to note here as well is the phase.
Trapezoidal keeps the phase and amplitude correct at dc, cutoff, and
nyquist.
Nyquist? are you sure about that?
Yes, thanks for spotting that, I am so used to having nyquist warped
to inifinity that I use them interchanably in
rbj
another semantic to be careful about is transfer function.
we mean something different when it's applied to LTI systems
(the H(z) or H(s)) than when applied to a diode. the latter
semantic i don't use. i would say volt-amp characteristic
of the diode or vacuum tube. or if it was a
On 6/22/14 10:41 PM, Andrew Simper wrote:
It is different for a circuit that isn't a 1 pole RC.
no, it's whenever an integrator (1/s in the s universe) is implemented
numerically with the trapezoid rule. doesn't matter whether it's a C or
anything else.
RBJ: please show me the derivation for
RBJ: direct integration like I am proposing is a good idea can be
solved in many ways, what results is a set of linearised equations to
be solved, these can be for nodal voltages, or differences in
voltages, the latter is called state space. Have a read of this:
DISCRETIZATION OF PARAMETRIC
On 6/22/14 11:24 PM, Andrew Simper wrote:
so whether it's a function of a single variable or a function of two
variables with your previous output in recursion, why not just explicitly
define that function and evaluate it? if it's about tube curves being the
nonlinearity inside, fine, use your
you
have a function of two variables that you can explicitly evaluate
using your favourite route finding mechanism, and then use an
approximation to avoid evaluating this at run time. This 2D
approximation is pretty efficient and will be enough to solve this
very basic case. But each
sigh sigh sigh please at least try and understand what I wrote
before sighing at me! Yes, I agree that for low dimensional cases this
is a good approach, but for any realistic circuit things get
complicated and inefficient really quickly and you are better off with
other methods.
What I mean
On 6/23/14 12:16 AM, Andrew Simper wrote:
you
have a function of two variables that you can explicitly evaluate
using your favourite route finding mechanism, and then use an
approximation to avoid evaluating this at run time. This 2D
approximation is pretty efficient and will be enough to solve
On 23 June 2014 11:25, robert bristow-johnson r...@audioimagination.com wrote:
On 6/22/14 10:48 PM, Andrew Simper wrote:
I think the important thing to note here as well is the phase.
Trapezoidal keeps the phase and amplitude correct at dc, cutoff, and
nyquist.
Nyquist? are you sure about
I think you should look at this like a tool set. Table look up is one tool that
you can use as it iterative function evaluation. What tools you use depends on
circumstances. On the PC platform you have big caches, lots of memory and real
fast CPU clocks. If you go FPGA clock rate goes down as
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