Motorboat is DMA buffer underruns. This is an D44 setting in the D44
control panel.
Here is the solid relationship you can count on.
M-Audio D44 DMA Buffer <= Power SDR Audio Buffer or Motorboat will occur.
I can repeat this ad infinitum.
DSP buffer size can be smaller than Audio Buffer or larger than Audio
buffer.
They are no longer constrained since we have the ring buffer mechanism
perfected.
<<<The limitations will be determined by your computer and what you have
on it >>>
The reasons for the super tiny audio buffers before was the way cw was
being generated
before. We no longer need these super tiny buffers for the new keyer.
I have the ring
buffers minimized for latency in the keyer. This sets a MAXIMUM buffer
size of 1024
for the AUDIO. Let the dsp be whatever it wants to be.
Even when the callback is not happening, the parallel port is being
read and the keyer state
is constantly being updated with new input and a ring buffer is being
filled with data for the
next callback by the keyer.
I can run, on my 3.4 Ghz P4 HT with D44 DMA buffers of 128, Audio of
256 and DSP
of 256 and not get a single underrun. But that puts a severe cramp on
the filter quality.
The 250 Hz filter is no better than the 500 Hz filte which is not much
better than the 1Khz filter.
This changes dramatically at DSP = 512 and again at DSP=1024. I can
send 40 wpm with
perfect keying with 1024/1024 for audio/dsp. Set your D44 DMA buffers
smaller or equal
to 1024. Mine came default to 2048!! I had motorboat until I set them
<<< TODAY>>>.
WARNING WARNING DANGER WILL ROBINSON:
So, as you make each of these numbers smaller, you go to the Kernel
context switch, interrupt
process, etc. not-so-deep well more often. You can run the well dry.
Here is what I am certain of. You will not run your machine on small
audio buffers with small
dsp buffers if you cannot set small DMA buffers. For those of you with
asio4all, you will need
to set the buffers accordingly in that control panel. The smaller
buffers will allow smaller portaudio
buffers to be set and smaller dsp buffers to be set.
Contrary to what you might believe, the "CPU meter" does not change
much. What changes
is the amount of time spent in system calls and makes your machine more
susceptible to
interference by those 29 things you have loaded on your computer so you
can make sure
this email message is not spam, does not have a spyware, and is not
loaded with malware
of any type. All of those things hurt your computers performance and I
know as well as
anyone how impossible it is to live without them. Just be aware of the
facts.
I have all of the keyer controls on the form. Eric and I put Speed is
on the front panel. I have
weight, ramp, and iambic inside on the DSP tab where it doesn't belong
but where I had room.
Sidetone frequency is set by CW tone freq on the DSP panel.
We will work on switching automagically tomorrow and likely Friday.
More later.
Bob
.
