"Jerry Avins" <jya@ieee.org> skrev i meddelandet
news:40d6e9e0$0$3040$61fed72c@news.rcn.com...
> Martin Thompson wrote:
>
> > Jerry Avins <jya@ieee.org> writes:
> >
> >
> >>Kunal wrote:
> >>
> >>
> >>>I am making a Digital Dictation Machine and I need a solution to
> >>>digitize the voice, compress it and store it on a flash chip. It
> >>>should then also be able to decompress it and play it back through a
> >>>d/a. I need to control it using I2C.
> >>
> >>What Is I2C? I have much to learn.
> >
> >
> > Inter-Integrated-Circuit (IIC), also I-squared-C, hence I2C in boggo
> > text.>
I2C is a 400Kbit transmission capacity link - offen used for signaling stuff
to
chips. One can figure it as a "USB cord" for chips design puroposes.
> ...
>
> Thank you, Sir. "Boggo" is also new to me, but I can deduce it.
>
> Jerry
> --
> Engineering is the art of making what you want from things you can get.
> �����������������������������������������������������������������������
>
Reply by ●June 22, 20042004-06-22
Jerry Avins <jya@ieee.org> writes:
...
>
> Thank you, Sir. "Boggo" is also new to me, but I can deduce it.
>
You're welcome! "Boggo" may be a UK-ism, or maybe just a me-ism...
Cheers,
Martin
--
martin.j.thompson@trw.com
TRW Conekt, Solihull, UK
http://www.trw.com/conekt
Reply by yo●June 21, 20042004-06-21
Mu has the 13 bits. I could never get a clear picture of a law.
"Jerry Avins" <jya@ieee.org> wrote in message
news:40d6e94c$0$3040$61fed72c@news.rcn.com...
> Jim Thomas wrote:
>
> > Jerry Avins wrote:
> >
> >> I suppose that's a saving. Anyhow it stores 12 bits of dynamic range in
> >> 8 bits of storage space.
> >
> >
> > Hi Jerry,
> >
> > I could be wrong, but I think A-law starts with one more bit than
> > mu-law. I don't recall if mu/A are 12/13 or 13/14 though. I'm pretty
> > sure one of them starts with a 13-bit word though.
>
> Thanks. Live and loin. (Chop chop!)
>
> Jerry
> --
> Engineering is the art of making what you want from things you can get.
> �����������������������������������������������������������������������
>
Reply by Jerry Avins●June 21, 20042004-06-21
Martin Thompson wrote:
> Jerry Avins <jya@ieee.org> writes:
>
>
>>Kunal wrote:
>>
>>
>>>I am making a Digital Dictation Machine and I need a solution to
>>>digitize the voice, compress it and store it on a flash chip. It
>>>should then also be able to decompress it and play it back through a
>>>d/a. I need to control it using I2C.
>>
>>What Is I2C? I have much to learn.
>
>
> Inter-Integrated-Circuit (IIC), also I-squared-C, hence I2C in boggo
> text.
...
Thank you, Sir. "Boggo" is also new to me, but I can deduce it.
Jerry
--
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������
Reply by Jerry Avins●June 21, 20042004-06-21
Jim Thomas wrote:
> Jerry Avins wrote:
>
>> I suppose that's a saving. Anyhow it stores 12 bits of dynamic range in
>> 8 bits of storage space.
>
>
> Hi Jerry,
>
> I could be wrong, but I think A-law starts with one more bit than
> mu-law. I don't recall if mu/A are 12/13 or 13/14 though. I'm pretty
> sure one of them starts with a 13-bit word though.
Thanks. Live and loin. (Chop chop!)
Jerry
--
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������
Reply by ●June 21, 20042004-06-21
Jerry Avins <jya@ieee.org> writes:
> Kunal wrote:
>
> > I am making a Digital Dictation Machine and I need a solution to
> > digitize the voice, compress it and store it on a flash chip. It
> > should then also be able to decompress it and play it back through a
> > d/a. I need to control it using I2C.
>
> What Is I2C? I have much to learn.
Inter-Integrated-Circuit (IIC), also I-squared-C, hence I2C in boggo
text.
A 2-wire protocol invented (and licensed by I think) Philips for
low-speed comms between ICs. Multi-drop - each type of slave has a
unique ID. Some can be configured to several different IDs, so you can
hang several instances of a single IC off one I2C bus and communicate
with them all.
Examples are EEPROMs, lots of video chips (digitisers, scalers etc),
cameras.
The full spec can be found on the Philips website I think.
Cheers,
Martin
--
martin.j.thompson@trw.com
TRW Conekt, Solihull, UK
http://www.trw.com/conekt
Reply by Jim Thomas●June 21, 20042004-06-21
Jerry Avins wrote:
> I suppose that's a saving. Anyhow it stores 12 bits of dynamic range in
> 8 bits of storage space.
Hi Jerry,
I could be wrong, but I think A-law starts with one more bit than
mu-law. I don't recall if mu/A are 12/13 or 13/14 though. I'm pretty
sure one of them starts with a 13-bit word though.
--
Jim Thomas Principal Applications Engineer Bittware, Inc
jthomas@bittware.com http://www.bittware.com (703) 779-7770
To mess up a Linux box, you need to work at it; to mess up your Windows
box, you just need to work on it. - Scott Granneman
Reply by Zak●June 20, 20042004-06-20
Symon wrote:
> The GSM vocoder gets voice down to 13 kbit/s (Search for 'Regular Pulse
> Excitation - Long Term prediction'). ulaw/alaw are 64 kbit/s. Last I was
> working with GSM, c.4 years ago, they (ITU-T) were talking about a 8 kbit/s
> vocoder.
There's Enhanced Full Rate and Half Rate CODECs in GSM these days.
Note that teh GSM codec does stuffliek comfort noise detection and
generation which the OP may not desire (coder detects type of background
noise, and decoder plays correct background noise when no speech bits
are transmitted or received).
Thomas
Reply by Martin Blume●June 19, 20042004-06-19
"Jerry Avins" schrieb
> Leon Heller wrote:>
> > > What Is I2C? I have much to learn.
> > I2C = 'Inter-IC' - Philips's two wire bus for comms
> > between ICs.
You might have an I2C bus in your PC, as this is IIRC used
for temperature measurements (CPU, mainboard), perhaps
as well for dynamic fan control.
You might want to have a look at
http://www.philipslogic.com/products/i2c/
Regards
Martin
Reply by Tony●June 19, 20042004-06-19
A lot of the tiny MP3 players out there can also record/compress from
mic input. For a dictation machine you could code to as low as 16kb/s
with useful results. If you want to roll your own instead of hacking a
bought device, the MP3 player chips are easy to find and well
documented, and I believe Microchip and TI (at least) have apnotes
showing how to use their products in that application, and TI also
have MP3 (and other) libraries for their DSPs (ask them). There are
more efficient compression methods, but they generally take way more
code and horsepower for the compression process, and MP3 is way more
universal anyway.
Of course there are no/low-cost PC-based MP3 dictation machines out
there, but I assume you need to be independent of a PC or laptop?
On 18 Jun 2004 13:17:39 -0700, kunalshenoy@hotmail.com (Kunal) wrote:
>I am making a Digital Dictation Machine and I need a solution to
>digitize the voice, compress it and store it on a flash chip. It
>should then also be able to decompress it and play it back through a
>d/a. I need to control it using I2C.
>
>Questions:
>1) Which are the latest voice compression algorithms out there?. i
>know of a-law u-law, but what about the ones used in cell phones and
>other new ones.
>
>2) I found "voice band audio processors" at ti, are these suited to my
>application? Although they dont provide for external memory access,
>could I use them for the compression atleast?
>
>3)Another path would be to use a general purpose DSP chip and then
>program it. This way i could get the peripheral support and still get
>compression. Since this is a portable application, i plan to use the
>5000 (low power)series. Could you help me narrow down this choice to a
>specific chip or how should i estimate my processing needs.
>
>4) any other useful information would be great:
>
>Kunal