digitization of sensor array

[bhatti]

Hi all

I need to digitize a 32 channel sensor array, hosed in a pipe of 50m
diameter and 6m length. Sensors are hydrophones integrated wit
preamplifiers. Simultaneous sampling is required with 20Ksamp/s/ch be th
required sampling rate.

To further complicate the matter, I need to send digitized data over 1000
quad cable (AWG30) or coaxial cable.One thought was to send digitized dat
over ethernet format but it had its own problems and limitations (a
mentioned in my previous post).

Can any one give me the idea how to accomplish this task?The hardware for
digitization and data sending needed to be fitted in 50mm dia pipe.I hav
used cirrus logic CS5368 8 channel ADC IC and with four of these ICs i ca
digitize whole array but one problem i face is how (and on what format) t
send the combine data over 1000m quad/coaxial cable(i have limitations t
use repeaters or optical fiber).

This will be a prototype designing which if successful will extend to a 12
channel sensor array.

Any other soution or idea will be much appreciated.

Best Regards


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[RCIngham]

Because your sensor array length is only 6m, you shouldn't get problem
with sampling strobe skew.

Is this eventually going to be a production system? If so about how many?

The reason that I ask is that if both are one-offs, the component cost i
less important than for a production system, but the design cost and ris
are more important.



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[Kolja Sulimma]

The data rate is rather low. 640ksps at 16 bits is only 12.8MBbps.
You can have one chip for each ADC, daisy chained to create one common
bitstream from all the sources.
This can be accomplished in very small FPGAs or in a CPLDs. With the
right protocol you could also
use a microcontroller.

The last chip can send this data using any technology that can provide
this bitrate at the desired distance.
You can either use standard hardware and protocols (eg. ethernet or
one of the DSL variants)
or given the simple application you can roll your own protocol using a
phy for one of these technologies.

If you build only one of these, microcontrollers with ADC interfaces
and ethernet that connect to an SDSL-Modem are
probably the easiest to do.

Kolja
cronologic

 

[bhatti]

If you build only one of these, microcontrollers with ADC interfaces >an
ethernet that connect to an SDSL-Modem are >probably the easiest to do.
Kolja >cronologic

Thanks for your reply.I have searched SDSL modems on internet but i coul
not find any modem that can be fitted in 50mm diameter pipe.If you hav
seen any such modem kindly share it.

Thanks

Best Regards

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