03-24-2009 08:55 AM
harlow, to everyone!!
What is ur opinion is use DAQ USB6009 to read signal we get from the brain?
the resolution for USB 6009 is 14-bit. are this enough??
sample rate is 48 kS/s
the min voltage is (-1/+1) but our brainwave only around 10UuV, this can be slove if we gain it till 1V
is around 1000 times.
will this spoil the wave n more noise?
My design for amplifer is Instrument Amplfier --> low pass -=-> high pass ---> amplifer (100times) --> notch flier--> non-inverting amplifer--->otocouple.
any idea for it?
03-25-2009 04:58 AM
03-25-2009 12:02 PM
The resolution will be enough - the dynamic range of EEG signals is not that great (unless you need to capture EEG during a seizure). 12-bits is plenty. One possible issue is that the 6009 product is a multiplexed A/D so each channel is scanned/sampled in sequence, which could lead to loss of accurate phase information. This may or may not be a concern for you depending on how the data will be collected and used.
There are still lots of analog optical isolation modules on the market - search for "isolation amplifiers". Analog Devices has a good selection. Battery power for the front-end makes a lot of sense, but you still need to be worried about DC fault currents even from the battery. AC coupling the instrumentation amplifier solves this issue, as well as blocking the DC offsets from typical surface electrodes.
03-26-2009 10:30 AM