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ADC to PC; best/better solution

Tomas Kratochvil

Nov 3, 2015
2
Joined
Nov 3, 2015
Messages
2
Hello,

I need help with my project. It´s about A-scan ultrasound, used for eye biometry(more here: http://emedicine.medscape.com/article/1228447-overview). It will serve as a learning tool at my school.

I want to get signal from ADC to PC:
ADC -> buffer -> ATXmega -> USB -> PC
or
ADC -> parallel-to-USB converter -> PC

FPGAs are commonly used in ultrasound devices, but I want to avoid them, because I have no experience with them.

Specifications:
-one data channel
-trandsucer resonence frequency - 2,25 Mhz
-8 bit external ADC atleast 22,5 MSPS
-powering, data and commands via USB
-only data bursts - not continuous data flow:
-ultrasound velocity in water = 1540 m/s = 1.54 mm / us
-eye ball diameter doubled = 50 mm
-one measuring will take 50/1.54 = 32.5 us
-> 22,5 sample on 1 us -> 32.5*22,5*8 = 5850 bits from one measuring
-> 730 bytes per one measurent

I found ADC08B200 from TI, it suits my needs with 8bit, sampling rate, 1kB buffer...

Questions:
Do you know about ADC with bigger buffer memory?
Do you know about any parallel-to-USB converter? Maybe with FTDI chip (didn´t find any that suits my requirements).

I have found few boards like this (http://store.redpitaya.com/red-pitaya-board-35.html) but it is overkill for my project.
 

AnalogKid

Jun 10, 2015
2,665
Joined
Jun 10, 2015
Messages
2,665
Nice part. The Atmel XMEGA series has more than enough I/O pins and horsepower to act as the interface between the ADC and USB. So will any of the FTDI modules, or even an Arduino depending on how long the gap is between data bursts.

ak
 

Tomas Kratochvil

Nov 3, 2015
2
Joined
Nov 3, 2015
Messages
2
Hello, thank you for you reply.
I know, but my fear is about the speed.

Can you help me with my questions?
"Do you know about ADC with bigger buffer memory?
Do you know about any parallel-to-USB converter? Maybe with FTDI chip (didn´t find any that suits my requirements)."

Did I put this thread to correct folder?
 
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