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Precision Amplifiers Forum
INA326 EMG amplifier
I'm trying to make an EMG front end amplifier with an INA326 and several OP amps for respective HP/ LP filtering. Could someone point me in the right direction with building such a device?
I'll be using filterpro for the hardware HP/LP filters with OP233's. What i understand is that there is no need for a right leg driver, like in ECG designs. I was told to High pass the signal first then low pass it. Wouldn't most of the noise exist in the High Frequency end?
My constraints for EMG are
large muscle use -amplitude from 0-10mV
Smaller muslces - amplitude from 0-1.5mV
0-500Hz freq range, with dominant energy in the 50-150Hz range.
As this EMG device will be on a wireless device, the subject will be moving. Will i need a right leg driver for signal fidelity.
Thanks in advance for any help or advice whatsoever.
The INA333 is a good choice. It meets your 5Vdc supply requirement and has low Vos and low Vos drift.
Precision Analog Applications
I implemented EMG circuit using LM308 for instrumentation amplifier. This picture might give you a better idea of the same:
Now, instead of using LM308, I am using INA 101 and also, instead of single channel, I am designing it to be multichannel. I had a few questions about INA 101, is there any technical stuff like application or example circuits available for INA 101 (I went through the data-sheet). Also, are there any multi-channel circuit diagrams available (EMG, ECG or EEG) all are same except for filtering.
Thanks in advance,
Hello sir ,can u plz attach the tina schematic for in326 amplifier
hello sir can u plz attach the tina schematic of the above post
thanks and regrds
Who's design are you after? Mine was riddled with noise. It requires a lot of trial and error and playing with the right filters to get a good signal. It also depends on the application whether small or large muslce stimuli is being measured.
Perhaps TI could provide some templates or a design guide.
Agreed. Most bio-sensor designs do require careful shielding and customized application-based filtering. Some of the circuits posted in this thread serve as a good starting point but are by no means complete. TI does not currently have a design guide for EMG systems, but this is definitely a good suggestion and something to target moving forward.
Sorry for getting this topic back from ages ago but i belive it is better than creating a new as it got a lot of good discussion in special about INA333. On my design i cant use DLR circuit as i need to go for dual electrode system. I designed a couple EMG amps in the past with the good old AD620 but using DLR circuit and it worked properly. Simple question, if i go to the ac coupled electrodes approuch following the design propoded a the ieee article, would be a problem to tie the center reference (in the middle of the resistors) to my middle reference (1.65V for instance)? An important fact is that that reference point is created spliting my supply with two precision resistors and using a OPA333 as voltage follower. I would do that so i can create the bias for the INA333 inputs and kill any electrodes offset improving my INAMP amplification. Thank you!
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