ADS1292R starting questions

Hi Sami,

I will do my best to help answer your questions in red-

1. Do I need to use amplifiers to amplify ECG signal before ADS1292r? If yes ; do you suggest cisruits or application notes? Measuring ECG signals can be accomplished directly with the ADS1292 or ADS1292r without a need for an external amplifier. Adding an external amplifier is going to add noise to an, already, noise sensitive system.
2. My design will be one lead ecg ; only two electrodes; so how can i use pseudo RLD with ADS1292R ? One way is to AC couple the inputs and then use either the RLD or midpoint between the two power supplies to set the bias point at the the input pins using weak pull up resisters. As shown below  

1. In the kit of ADS1292R ; there are 3 digital filters impelmented ; IIR, FIR and notch ; where I can find the codes of these filters ?  Depending on what you are interested in, the filtering was either done in the MSP430 firmware or in labview. The firmware has the filtering that is used during LIVE ECG Display which shows the ''streaming'' data in the GUI. The MSP430 firmware is found here:  C:\Program Files\Texas Instruments\ADS1x9xevm\Firmware. The Analysis tab uses filtering that is done in labview. If you are interested in that source code, let me know and I can get it to you.

 Regards,

Tony Calabria

Thank you Tony ;

I will tell you the results during my development;

I will use l bipolar power supplies ; so i will tie them to 0 volt (Avss  middle point) that what i understand from your post , Am I right?

Do I need in this case a low pass filter two after the AC couple ?

I dont have that link in my pc ; where do i install them kit softwares?

Regards

Hector

 If you are interested in that source code, let me know and I can get it to you.

Hi  Tony

Yes please ; could you give the source code ?

Regards

Hector

Hello

T o the analog guys ; Please check my first prototype shematic with ADS1292R and let me know please if i have something wrong .

I use channal 2 for reading ECG  ; because channal one will be used for respiration .

I use RLDout with 10M ohms resistor directly to the ECG signals ; because I use only 2 electrodes reading .

I use 22.2k ohms ,  with 6.8nF to forum a lowpass filter of cuttoff frequency about 1kHz for anti- aliasing ; my sample frequency will be maximum 500SPS.

I use +5v/-5v for ADS1292R and 3.3v for digital . 

I use internal oscillator.

I leave the unused pins floated.

I hope you could guide me to add pace detection to this circuit.

Thank you in advance.

 1423.ECG_MODULE_R_1.0.PDF

Thank you alot ;

I would be happy if someone could guide me to get good pace detector circuit too ; I? have googled around but nothing ...

Regards

Hector

Hi Hector,

We are in the process of doing some testing on a hardware pace detection circuit to be used with the ADS129x family of devices. Check back or post here again in about two weeks to give us time to complete testing and I can let you know how it turned out as well answer any questions you may have.

Regards,

Tony Calabria

Hello all,

Started to use the ADS1292R but I am not sure about what power supply is needed to make run the respiration and EKG funtionalities properly. The datasheet says that two are needed, an analog one and a digital one,can they be the same power supply?,so they  have the same value (3.3V)?, My analog signals won't go over 3.3 V and my Uc runs with 3.3 V as well.

Thanks in advance!

Yes

Thanks, i will connect the analog and digital voltage pins to the same power supply of 3.3 V then.

I would use bipolar supplies +5/-5 ; do you suggest me to use a unipolar 0-3.3v?

Jario could you share your shematic? Or could you check my shematci please ?

Regards

Hector,

It really depends on circuit design and the components you are working with. I dont really use 5/-5 supplies anymore as they considered by some literature authors as obsolete; because they need to be referenced to dc level when passing through a Uc, but it is up to you.

I highly recommend to use unipolar ones.

Regarding the schematic I am using the "ADS1x9xECG.pdf" file, page 51. http://www.ti.com/lit/ug/slau384a/slau384a.pdf

or if you insist with bipolar,  on page 60 of the "ads1292r.pdf" file there is a good option.  http://www.ti.com/lit/ds/symlink/ads1292r.pdf

Don't forget to set the internal reference  by setting the CONFIG2 register.

Cheers,

Hi Tony

Any progress  about the pace detector cırcuit?

Thank you

Hector,

In the testing process.

Will get back to you once completed.

Regards,

Tony Calabria