Reply by Micah Stevens January 20, 20052005-01-20
Haha.. I find most of my accomplishments come by accident.. 

On Thursday 20 January 2005 02:32 am, onestone wrote:
>  There is obviously a finite limit, but I suspect it will be far smaller
>  than many people realise. I occasionally spend a few hours on my own
>  version of MP3, started in 1994. I now have it to `15:1 compression with
>  3% rms distortion of the original signal, but am still a long way from
>  the target of 38:1. I achieved my compression using 'models',
amongst
>  other things. It was just an interesting aside on your comment regarding
>  word contraction. Incidentally I got there purely accidentally. I
didn't
>  know anything about DSP algorthms, or DSP tools. They were in their
>  commercial infancy then, and information suitable for a beginner 30
>  years out of high schoool was very difficult to find. (A lot of branches
>  of modern electronics use a symbology that has a totally different
>  meaning to when I was taught.) I set out to try and derive a way to
>  extract the single most dominant pure tone from a complex audio
>  waveform. I ended up, after quite a while, with my compression
>  algorithm, and a filter with odd properties.
>
>  So not everything I do is by design. ;@}
>
>  Al
>
>  Micah Stevens wrote:
>  > On Wednesday 19 January 2005 05:27 pm, onestone wrote:
>  >> So preservation of the english language now becomes a good excuse
to be
>  >> anti-social. :@}
>  >>
>  >> More seriously, many years ago when I first started working on
voice
>  >> codecs I developed a rather odd voice compression method, and, in
a
>  >> series of experiments, over 3 years, eventually increased the
>  >> compression ratio such that a 16 bit recording, at 8000sps
(128000 bits
>  >> per second) reduced to 600 bits. I was told (by a whole bunch of
>  >> faculty at melbourne university) that it was impossible to reduce
data
>  >> this far and still retain intelligence that would still enable
the
>  >> content to be clear. So I demonstrated it to them. Not only was
the
>  >> speech clear enough to be easily intelligible, but you could
readily
>  >> recognise the speaker as well. Sure it echoed, had a few pure
>  >> sinusoidal artifacts, and clicks and pops, but it went to show
that
>  >> theory is only that, until someone proves or disproves it. Just
to
>  >> grandstand a little I reduced it still further. It got a bit
messy,
>  >> like listening under a shower, but even at 300bps you could make
out
>  >> the original data.
>  >>
>  >> So, when someone tells me you can only reduce something so far I
remain
>  >> skeptical until I've failed.
>  >>
>  >> Al
>  >
>  > Well, I didn't state an actual limit, but I think you'll
agree that it's
>  > self evident that if compression increases until the data no longer
>  > contains meaningful information, then it's too far.
>  >
>  > As to what that actual limit is, that's another issue. :)
>  > -Micah
>  >
>  >
>  > .
>  >
>  >
>  > .

Beginning Microcontrollers with the MSP430

Reply by onestone January 20, 20052005-01-20
There is obviously a finite limit, but I suspect it will be far smaller 
than many people realise. I occasionally spend a few hours on my own 
version of MP3, started in 1994. I now have it to `15:1 compression with 
3% rms distortion of the original signal, but am still a long way from 
the target of 38:1. I achieved my compression using 'models', amongst 
other things. It was just an interesting aside on your comment regarding 
word contraction. Incidentally I got there purely accidentally. I didn't 
know anything about DSP algorthms, or DSP tools. They were in their 
commercial infancy then, and information suitable for a beginner 30 
years out of high schoool was very difficult to find. (A lot of branches 
of modern electronics use a symbology that has a totally different 
meaning to when I was taught.) I set out to try and derive a way to 
extract the single most dominant pure tone from a complex audio 
waveform. I ended up, after quite a while, with my compression 
algorithm, and a filter with odd properties.

So not everything I do is by design. ;@}

Al

Micah Stevens wrote:
> On Wednesday 19 January 2005 05:27 pm, onestone wrote:
> 
>> So preservation of the english language now becomes a good excuse to be
>> anti-social. :@}
>>
>> More seriously, many years ago when I first started working on voice
>> codecs I developed a rather odd voice compression method, and, in a
>> series of experiments, over 3 years, eventually increased the
>> compression ratio such that a 16 bit recording, at 8000sps (128000 bits
>> per second) reduced to 600 bits. I was told (by a whole bunch of
faculty
>> at melbourne university) that it was impossible to reduce data this far
>> and still retain intelligence that would still enable the content to be
>> clear. So I demonstrated it to them. Not only was the speech clear
>> enough to be easily intelligible, but you could readily recognise the
>> speaker as well. Sure it echoed, had a few pure sinusoidal artifacts,
>> and clicks and pops, but it went to show that theory is only that,
until
>> someone proves or disproves it. Just to grandstand a little I reduced
it
>> still further. It got a bit messy, like listening under a shower, but
>> even at 300bps you could make out the original data.
>>
>> So, when someone tells me you can only reduce something so far I remain
>> skeptical until I've failed.
>>
>> Al
> 
> 
> Well, I didn't state an actual limit, but I think you'll agree
that it's self 
> evident that if compression increases until the data no longer contains 
> meaningful information, then it's too far. 
> 
> As to what that actual limit is, that's another issue. :) 
> -Micah 
> 
> 
> .
> 
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
> 
> 


Reply by Micah Stevens January 19, 20052005-01-19
On Monday 17 January 2005 10:35 am, Sepp Holzmayr wrote:
>  Just had one of my Under-The-Shower-Ideas....
will only work if you're
>  not going to process data between getting and transmitting. But look:
>  (Same assumptions as in my last mail!!)
>
>  int buffer;
>  char *transmit;
>
>  int GetADVal1 (void);
>  int GetADVal2 (void);
>  void SendByte (char x);
>
>  ...
>
>  buffer = (GetADVal1() & 0x0FFF);
>  transmit = &buffer;
>  SendByte(*transmit);
>  buffer = ( (buffer & 0x0F00) >>8 ) & ( (GetADVal2 &
0x0FFF) <<4 );
>  SendByte(*transmit++);
>  SendByte(*transmit);
>

Hey Sepp, 

Just so I know your strategey, can you tell me if this is what's happening?

1) Get first 12 bit conversion and place it in a 16 bit variable
2) let transmit point to the memory location of the buffer variable
3) send the lower 8 bits of the memory location referred to by transmit
4) let buffer be equal to the upper 4 bits of the original sample, shifted 
down to the lower 4 bits, and then put the second sample in the upper 12 bits 
of the variable by shifting it up 4 places.

5) (this is what I'm unclear on due to my inexperience in c) Send the lower
8 
bits of the variable, then increment the transmit pointer, which would then 
push it 8 bits higher in memory? (or does a pointer increment on the MSP go 
16 bits higher in memory?) 

6) send this upper 8 bits..

I would do this a little different by losing the pointer and doing more bit 
shifting, but maybe the pointer method is more effiecient? Any ideas on this?

My translation: 

 buffer = (GetADVal1() & 0x0FFF);
 SendByte(buffer);
 buffer = ( (buffer & 0x0F00) >>8 ) & ( (GetADVal2 & 0x0FFF)
<<4 );
 SendByte(buffer);
 SendByte(buffer >> 8);

Any thoughts on the difference? 

-Micah 

Reply by Micah Stevens January 19, 20052005-01-19
On Wednesday 19 January 2005 05:27 pm, onestone wrote:
>  So preservation of the english language now
becomes a good excuse to be
>  anti-social. :@}
>
>  More seriously, many years ago when I first started working on voice
>  codecs I developed a rather odd voice compression method, and, in a
>  series of experiments, over 3 years, eventually increased the
>  compression ratio such that a 16 bit recording, at 8000sps (128000 bits
>  per second) reduced to 600 bits. I was told (by a whole bunch of faculty
>  at melbourne university) that it was impossible to reduce data this far
>  and still retain intelligence that would still enable the content to be
>  clear. So I demonstrated it to them. Not only was the speech clear
>  enough to be easily intelligible, but you could readily recognise the
>  speaker as well. Sure it echoed, had a few pure sinusoidal artifacts,
>  and clicks and pops, but it went to show that theory is only that, until
>  someone proves or disproves it. Just to grandstand a little I reduced it
>  still further. It got a bit messy, like listening under a shower, but
>  even at 300bps you could make out the original data.
>
>  So, when someone tells me you can only reduce something so far I remain
>  skeptical until I've failed.
>
>  Al

Well, I didn't state an actual limit, but I think you'll agree that
it's self 
evident that if compression increases until the data no longer contains 
meaningful information, then it's too far. 

As to what that actual limit is, that's another issue. :) 
-Micah 

Reply by onestone January 19, 20052005-01-19
So preservation of the english language now becomes a good excuse to be 
anti-social. :@}

More seriously, many years ago when I first started working on voice 
codecs I developed a rather odd voice compression method, and, in a 
series of experiments, over 3 years, eventually increased the 
compression ratio such that a 16 bit recording, at 8000sps (128000 bits 
per second) reduced to 600 bits. I was told (by a whole bunch of faculty 
at melbourne university) that it was impossible to reduce data this far 
and still retain intelligence that would still enable the content to be 
clear. So I demonstrated it to them. Not only was the speech clear 
enough to be easily intelligible, but you could readily recognise the 
speaker as well. Sure it echoed, had a few pure sinusoidal artifacts, 
and clicks and pops, but it went to show that theory is only that, until 
someone proves or disproves it. Just to grandstand a little I reduced it 
still further. It got a bit messy, like listening under a shower, but 
even at 300bps you could make out the original data.

So, when someone tells me you can only reduce something so far I remain 
skeptical until I've failed.

Al

Micah Stevens wrote:
> 
>> I understand now! So ultimately the language becomes amazingly
>> efficient. every word sequence that starts with 'a' and ends
with ight,
>> or ite, becomes contracted to just a single word "aight", of
course this
>> helps with maths as well, since, in many regional accents this is also
>> the nu'er that co'es a'er s'en and b'ore nine.
:@}
>>
>> Al
> 
> 
> Well, keep in mind that it's not an infinite regression. You can only
compress 
> data so far, beyond which at a certain point it no longer contains any of
the 
> original message. So there is a social understanding of the meaning of the 
> contraction that contains the data. You cannot assume that it corresponds
to 
> every word that starts with a and ends with aight. 
> 
> Through social interaction the mind learns the context of the contraction. 
> ;)
> -Micah 
> 
> 
> .
> 
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
> 
> 


Reply by Micah Stevens January 19, 20052005-01-19
>  I understand now! So ultimately the language
becomes amazingly
>  efficient. every word sequence that starts with 'a' and ends
with ight,
>  or ite, becomes contracted to just a single word "aight", of
course this
>  helps with maths as well, since, in many regional accents this is also
>  the nu'er that co'es a'er s'en and b'ore nine.
:@}
>
>  Al

Well, keep in mind that it's not an infinite regression. You can only
compress 
data so far, beyond which at a certain point it no longer contains any of the 
original message. So there is a social understanding of the meaning of the 
contraction that contains the data. You cannot assume that it corresponds to 
every word that starts with a and ends with aight. 

Through social interaction the mind learns the context of the contraction. 
;)
-Micah 

Reply by onestone January 19, 20052005-01-19
Micah Stevens wrote:

>> aaiight sounds like a descent into neanderthal
protospeech. I've yet to
>> figure out if it means "shit the bugger bit me!", or
"Dad I got the
>> bastard, we eat now", "God was I ever constipated." or,
perhaps, damn,
>> who farted in the lift?"
> 
> 
> I find it just a good way to drop a syllable from alright.. I hate those
nasty 
> mid-word two-consonant syllable breaks.. 

I understand now! So ultimately the language becomes amazingly 
efficient. every word sequence that starts with 'a' and ends with
ight, 
or ite, becomes contracted to just a single word "aight", of course
this 
helps with maths as well, since, in many regional accents this is also 
the nu'er that co'es a'er s'en and b'ore nine. :@}

Al

> 
> -M
> 
> 
> 
> .
> 
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
> 
> 


Reply by Micah Stevens January 19, 20052005-01-19
>  aaiight sounds like a descent into neanderthal protospeech. I've
yet to
>  figure out if it means "shit the bugger bit
me!", or "Dad I got the
>  bastard, we eat now", "God was I ever constipated." or,
perhaps, damn,
>  who farted in the lift?"

I find it just a good way to drop a syllable from alright.. I hate those nasty 
mid-word two-consonant syllable breaks.. 

-M


Reply by onestone January 19, 20052005-01-19
Micah Stevens wrote:
> 
>> > I understand you guys down below are a little behind the times in
slang,
>> > but you can't blame me for that. ;)
>>
>> Oh I'm well aware of the slang, we hear it all on imported TV all
the
>> time. It's just that I refuse to descend to the level of intellect
that
>>   reverts to imbecilic slang to fit some street thug proto image. ;?}
>>
>> No offence to you. I just can't believe that the US has descended
so far
>> intellectually that once respected TV presenters are now reduced to a
>> vocabularly that revolves around aaaaight, word and other meaningless
>> vocal farts.
> 
> 
> Haha.. most of the 'proper' english language we speak today was
once only the 
> realm of the common street thug.. Either that, or stolen from someone elses

> language. Or both. 

Language, thankfully is alive and growing, English primarily derives 
from latin, which, of course, came with influences from all the nations 
the squashed on the way there. English picked up a strong Saxon 
influence after the Romans left around the 5th century, and also 
rediscovered much of its Celtic heritage. English appeared to change 
little throughout the 'dark ages', although it is difficult to tell, 
since the written language was still primarily latin.  In 1066 the 
French became the last people to beat us up at a home game, (in fact 
they weren't truly French, but 'Normans', descendants of Britains
who 
had fled the Saxon purges) they also influenced the lagunage strongly. 
However since their language was largely a compote of the same origins 
as English, the changes were not quite as great they might have been. I 
would probably understand enough English, as spoken since the 13th 
century, to be able to communicate reasonably. The language has grown 
some, but the base has remained fairly consistent. Technological change 
has added much to the language, and much has been lost through outdated 
technology and customs. Much has been added to the language during our 
Empire building forays, but proportionally, only a very tiny amount of 
this change has been due to a descent into illiteracy. The most common 
type of change due to 'lower class' influence (not an ideal, simply a 
reference) has been the combining and contraction of words.

> 
> By using the words, I'm not defending the stance of the lesser
educated, but I 
> do think they are really good at coming up with monosyllabic utterances
that 
> often fit the bill.

aaiight sounds like a descent into neanderthal protospeech. I've yet to 
figure out if it means "shit the bugger bit me!", or "Dad I got
the 
bastard, we eat now", "God was I ever constipated." or, perhaps,
damn, 
who farted in the lift?"

Don't take me too seriously, I'm just having some fun ;@}

Al


Reply by Micah Stevens January 19, 20052005-01-19
>  > I understand you guys down below are a
little behind the times in slang,
>  > but you can't blame me for that. ;)
>
>  Oh I'm well aware of the slang, we hear it all on imported TV all the
>  time. It's just that I refuse to descend to the level of intellect
that
>   reverts to imbecilic slang to fit some street thug proto image. ;?}
>
>  No offence to you. I just can't believe that the US has descended so
far
>  intellectually that once respected TV presenters are now reduced to a
>  vocabularly that revolves around aaaaight, word and other meaningless
>  vocal farts.

Haha.. most of the 'proper' english language we speak today was once
only the 
realm of the common street thug.. Either that, or stolen from someone elses 
language. Or both. 

By using the words, I'm not defending the stance of the lesser educated,
but I 
do think they are really good at coming up with monosyllabic utterances that 
often fit the bill. 

>  >>Only if you are doing overly tough things
with it. Kris is the real
>  >>hardcore RF guy here. I like black box solutions. Simple devices
like
>  >>the RFM1000 are ridiculously easy to get running to meet their
basic
>  >>specs, while the nRF905 and its like are almost as easy, but far
more
>  >>flexible at a much lower price. If you want to squeeze every drop
of
>  >>performance or data rate sure it's not easy, but if you
follow the
>  >>reference designs and fairly basic design rules RF can be as easy
as any
>  >>other peripheral, like IIC/SPi etc.
>  >
>  > I'm using the nRF2401, and although in the docs it's simple
enough, and
>  > I have the eval boards doing flips for me, my board hooked to the MSP
>  > ain't doing diddly.. All I can get out of it is a carrier wave
in raw
>  > mode.
>  >
>  > Stupid chip.. (frustrated)
>
>  Of course it isn't the chip that's stupid (nor you I hasten to
add).
>  There is a big gap between lack of specific experience and stupidity.

Thanks, eventually I usually beat these projects into submission. 

>  > Just a quick sanity question, can anyone
confirm that the configuration
>  > data for the Nordic nRF2401 is clocked in most significant byte
first?
>  > (I know it's MSB first, but the docs are unclear as to the order
of the
>  > bytes.)
>
>  I've used the part, but don't have an answer to hand, as
I'm still not
>  in front of my main machine, and won't be for a few more days yet.
I'd
>  ask Kris, he'll have an answer for you I'm certain.

Once again, thanks for throwing in your help. Turns out for those interested, 
it is clocked in highest byte first, MSB first. Also the default SPI clock 
timing is incorrect for the chip, you need to offset the clock signal so your 
positive transitions occur mid-data. 

My other problem which took me a while at the o-scope to realize was that when 
the SPI transmit flag is set, that only means that the data is done being 
transfered into the TX buffer, it does not mean that the data has completed 
the actual transfer. So I was bringing the CE pin on the transceiver back 
down before the data was done getting to it. *sigh* A short pause fixed that, 
but I was wondering if anyone had a better way to deal with that problem? 

-Micah