I am trying to design an ultrasound system. I need to find a right ADC for it.
Transducer : 3.5MHz center frequency +- 10%
Signal bandwidth : Expect to be low. say 2~5MHz at most.
Unfocused. Beam is expected to spread from 0.05m.
Pulse repetition (!! key factor to choose ADC sps?) : 6kHz. In other words, every 0.000167 seconds shoot pulse.
How many samples : 128 samples. I want to make 128 samples per pulse transmission.
My rough calculation:
It seems, I need to sample 128 times every 0.000167 seconds.
It turns out ~768ksps required ( < 1 Msps). So i would choose 2~3Msps with 10 bits resolution.
Transmit pulse will be 5V. Not sure how much voltage I would get from receiving pulse (out of human body). Might be 100 times less (50mV).
I looked into some adcs that have 3Msps and 10bits. and I am not sure if the ADC will do this job.
With all those facts, which ADC will be capable of 3.5MHz signal with 768ksps required with very tiny voltage return?