delay chips and circuit

[mike e]

I need to put together a circuit that delays an audio signal a constant in the area of 1 mS. Reasonably good quality, perfect not required. The MN chips seem to be impossible to obtain more that a couple of. The ones I did find are 1024 stage BBD's which spec only to 2.56mS (lowest delay). The couple digital delay chips I've found on the internet had even higher minimum delay times. If any one has a source for the fewer stage BBDs or another delay method I'd appreciate the help! - Mike

 

[Spehro Pefhany]

On Tue, 16 Mar 2004 16:35:29 GMT, the renowned "mike e"
<20questions&nospam@optonline.net> wrote:

I need to put together a circuit that delays an audio signal a constant in the area of 1 mS. Reasonably good quality, perfect not required. The MN chips seem to be impossible to obtain more that a couple of. The ones I did find are 1024 stage BBD's which spec only to 2.56mS (lowest delay). The couple digital delay chips I've found on the internet had even higher minimum delay times. If any one has a source for the fewer stage BBDs or another delay method I'd appreciate the help! - Mike

1ms isn't very long. At an 8kHz "voice" sample rate, it's only 8
samples (and a bunch of filtering).

Howzabout a microcontroller, sample at 50-100kHz, shove 50-100 samples
into FIFO in internal RAM (100-200 bytes), output to DAC or whatever.
Details depend on what "reasonably good quality" means to you, but if
that's 12 bits in/out and 100k samples/second, then the Silicon Labs
C8051Fxxx series is an (expensive) one-chip solution (two built-in
12-bit DACs) that could provide up to a 23msec delay at 100k
samples/s. It could also do two channels at half the sample rate and
half the maximum delay.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Tim Wescott]

"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> wrote in message
news:2ece505ngmgl9a4ehf5j5uo0d7decib8of@4ax.com...

On Tue, 16 Mar 2004 16:35:29 GMT, the renowned "mike e"
20questions&nospam@optonline.net> wrote:

I need to put together a circuit that delays an audio signal a constant
in the area of 1 mS. Reasonably good quality, perfect not required. The MN

chips seem to be impossible to obtain more that a couple of. The ones I did
find are 1024 stage BBD's which spec only to 2.56mS (lowest delay). The
couple digital delay chips I've found on the internet had even higher
minimum delay times. If any one has a source for the fewer stage BBDs or
another delay method I'd appreciate the help! - Mike

1ms isn't very long. At an 8kHz "voice" sample rate, it's only 8
samples (and a bunch of filtering).

Howzabout a microcontroller, sample at 50-100kHz, shove 50-100 samples
into FIFO in internal RAM (100-200 bytes), output to DAC or whatever.
Details depend on what "reasonably good quality" means to you, but if
that's 12 bits in/out and 100k samples/second, then the Silicon Labs
C8051Fxxx series is an (expensive) one-chip solution (two built-in
12-bit DACs) that could provide up to a 23msec delay at 100k
samples/s. It could also do two channels at half the sample rate and
half the maximum delay.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers:
http://www.trexon.com
Embedded software/hardware/analog Info for designers:
http://www.speff.com

A company I used to work for did this with video to replace an analog delay
line -- it works quite well. You're not really losing anything over a BBD.

You might also consider a DSP with a built-in audio CODEC. Analog Devices
and TI (and probably more) have DSPs with built-in sterio-quality CODECs;
you're just a little bit of software away from a solution.

 

[John Woodgate]

I read in sci.electronics.design that Spehro Pefhany <speffSNIP@interlog
DOTyou.knowwhat> wrote (in <2ece505ngmgl9a4ehf5j5uo0d7decib8of@4ax.com&gt
about 'delay chips and circuit', on Tue, 16 Mar 2004:

1ms isn't very long. At an 8kHz "voice" sample rate, it's only 8 samples
(and a bunch of filtering).

A loudspeaker with a microphone a foot away is a very simple solution.
(;-)
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[CBarn24050]

Hi, loads of micros would eat this job for breakfast, too many to list but pic,
avr springs to mind.

 

[Tim Stinchcombe]

"mike e" <20questions&nospam@optonline.net> wrote in message
news:l1G5c.15667$F17.2331106@news4.srv.hcvlny.cv.net...
I need to put together a circuit that delays an audio signal a constant in
the area of 1 mS. Reasonably good quality, perfect not required. The MN
chips seem to be impossible to obtain more that a couple of. The ones I did
find are 1024 stage BBD's which spec only to 2.56mS (lowest delay). The
couple digital delay chips I've found on the internet had even higher
minimum delay times. If any one has a source for the fewer stage BBDs or
another delay method I'd appreciate the help! - Mike
----------------

Small Bear are showing 128-stage BBDs, MN3206

http://www.smallbearelec.com/Ordering/Stocklist.htm

(no idea if they are likely to have large quantities though).

Shanghai Belling actually make some of the old Panasonic chips, but
apparently only 1024, 2048 stages:

http://www.belling.com.cn/col89/article.htm1?id=1567

--
__________________________________________________________
Tim Stinchcombe

Cheltenham, Glos, UK

 

[mike e(remove & nospam fo]

Thanks for all the suggestions. I'm undecided spkr/mic may be the way to go here, though in fact I don't think the circuit needs a delay at all, but I'm not in charge of the project just researching. Thanks