Archive of the former Yahoo!Groups mailing list: ComputerVoltageSources

Hello all,

Soon, a new version of the gc-sah-sr-qua.bas will appear - Original
code written by Woody Wall and revised by Dave Brown.

This program converts the PSIM into a Serge Analog Shift Register -
actually several of them, allowing for up to 16 stages, which would
take 6 Serge triple ASRs to replicate.

Thanks so much to Dave Brown for his time this weekend in this effort
- I very much appreciate your incites on the PSIM.

After some experimentation, some realizations are evident to me.

1). Dave's analysis of the PSIM's accuracy is spot on. ALL PSIM
programs that are designed to have accurate input/output ratio
throughput should reflect Dave's research.

As Dave describes:

For input, the range is 1024 steps over 10 volts, or 9.76 mV
increments.

For output, the range is 4096 steps over 10.666 volts, or 2.60 mV
increments.

Thus to pass an input to output, the scale factor is (10/1024)X
(4096/10.666) which is 3.75.

Thus to scale the input to output, it needs to be multiplied by
3.75, (not 4). I typically multiply by 15/4 to keep the math
integer based.

Note that 10.666 volts was chosen to calibrate to semitone

[end Dave's quote]

2). For the purposes of a shift register application such as
gc-sah-sr-qua.bas, IMHO, quantization is unnecessarary.

First off, many of the patterns that one may want to "arabesque-asize"
with a Shift Register will be already quantized - this makes the
issues of "arguments" between the PSIM's interpretation of what the
input is possible - I found that, even with Dave's more accurate
input/out ratios installed that my PSIM was constantly arguing with my
Sequantizer about what pitch it should e playing.

Secondly, I found that the unquantized shift register is not only more
accurate, but the wider range of the unquantized version is much
better use when utilizing the Shift Register to controll non-pitched
modules. It is also much more accommodating to patterns with wider
pitch ranges (such as playing a sequence that spans more than two
octaves). In this regard, the unquantized version performs brilliantly.

Thirdly, the unquantized version operates identically the Serge Analog
Shift Register - which, for me, is the architypical Shift Register in
my life....

Gary