ADS1198: How to work with RLD

Hi,

Comments on question1 and 2 together -

Question 1: So, what sort of changes i need to do in my hardware as well as in its registers.

Question 2: How RLD works ?

Comments: please refer to datasheet page 58 59, you will need to try different combination to turn On and Off each switch, so that the differential signals after PGAxP and PGAxN can be fed to the inverting terminal of RLD Amp as summing amplifier to add the common mode noises. You should have an Integrator feedback circuit as shown in Cext and Rext in Figure 50. Then, after the RLD Amp, the added common mode noises should go out from RLDOUT pin and because of the integrator feedback circuit just mentioned, this output might be 180 degree phase shifted or inverted the original common mode noises. This way, it attenuates the original common mode noises from external. The non-inverting terminal of the RLD Amp, could be (AVDD+AVSS)/2 or your selected RLDREF voltage helps to drive/stabilize the human body or ECG simulator to a known reference voltage so when ECG signals are acquired from human body or ECG simulator, the ECG signals are not floating in an unknown voltage.

Customer will need to try different combination to turn On and Off each switch through trials, observing, collecting data, analysis to make decision for the appropriate switches combinations and gain settings.

I suggest start the tests, trials with one single channel first.

Question 3: When using RLD, do i need to disconnect WCT ?

No. Not necessary, unless you are using WCT as RLD; referring to the page 60 WCT as RLD section. It's option, but not necessary.

Question 4: If i need to get data with reference to RLD, do i need to remove all the negative connection except IN2N & IN3N ?

No, not necessary.  RLD is not used for reference unless you are doing WCT as RLD. Referring to the page 60 WCT as RLD section. It's option, but not necessary.

Suggest some good key words to study and understand ECG Right Leg Drive and ECG WCT.

Thanks.