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None of these ideas optimize the SNR that you need. You need to design with error correction or (suppression); 50V/m grid E-field (Right Led Drive RLD) >100 dB suppression AM radio noise (...
Answer
#2: Post edited
by
TonyStewart
·
2025-03-03T22:07:19Z (27 days ago)
- None of these ideas optimize the SNR that you need.
- You need to design with error correction or (suppression);
- - 50V/m grid E-field (Right Led Drive RLD) >100 dB suppression
- - AM radio noise (LPF > -40dB @ 1MHz)
- - Galvanic skin response (motion artifacts) (firm electrode strain relief)
- If you search for front-ends on EKG/ECG/EMG solutions you will find the best use the common-mode signal fed back to create a CM gnd somewhere on the body not moving much, away from the sensors. This becomes your signal ground but using good medical* isolated supplies or batteries will not conduct much (uA) current. *=low leakage rated/approved.
This can be done with a single supply using an INA if you choose the best Vref just below V+/2. You will never get 120 dB CMRR if you use 1% passives in the front-end and you net a 1% DM/CM error that's a 20 dB CMRR. This is why INA's are used with laser-trimmed errors.-  https://www.researchgate.net/profile/Chusak-Thanawattano/publication/261229670_Wearable_wireless_ECG_sensor_with_cross-platform_real-time_monitoring/links/566a430008ae62b05f0296c5/Wearable-wireless-ECG-sensor-with-cross-platform-real-time-monitoring.pdf
- --------------------------
-  https://www.analog.com/en/resources/analog-dialogue/articles/ecg-front-end-design-simplified.html
- None of these ideas optimize the SNR that you need.
- You need to design with error correction or (suppression);
- - 50V/m grid E-field (Right Led Drive RLD) >100 dB suppression
- - AM radio noise (LPF > -40dB @ 1MHz)
- - Galvanic skin response (motion artifacts) (firm electrode strain relief)
- If you search for front-ends on EKG/ECG/EMG solutions you will find the best use the common-mode signal fed back to create a CM gnd somewhere on the body not moving much, away from the sensors. This becomes your signal ground but using good medical* isolated supplies or batteries will not conduct much (uA) current. *=low leakage rated/approved.
- This can be done with a single supply using an INA ensuring that Vref is near V+/2.
- You will never get 120 dB CMRR if you use 1% passives in the front-end and you net a 1% DM/CM error that's a 20 dB CMRR. This is why INA's are used with laser-trimmed errors.
-  https://www.researchgate.net/profile/Chusak-Thanawattano/publication/261229670_Wearable_wireless_ECG_sensor_with_cross-platform_real-time_monitoring/links/566a430008ae62b05f0296c5/Wearable-wireless-ECG-sensor-with-cross-platform-real-time-monitoring.pdf
- --------------------------
-  https://www.analog.com/en/resources/analog-dialogue/articles/ecg-front-end-design-simplified.html
#1: Initial revision
by
TonyStewart
·
2025-03-03T22:05:00Z (27 days ago)
None of these ideas optimize the SNR that you need.
You need to design with error correction or (suppression);
- 50V/m grid E-field (Right Led Drive RLD) >100 dB suppression
- AM radio noise (LPF > -40dB @ 1MHz)
- Galvanic skin response (motion artifacts) (firm electrode strain relief)
If you search for front-ends on EKG/ECG/EMG solutions you will find the best use the common-mode signal fed back to create a CM gnd somewhere on the body not moving much, away from the sensors. This becomes your signal ground but using good medical* isolated supplies or batteries will not conduct much (uA) current. *=low leakage rated/approved.
This can be done with a single supply using an INA if you choose the best Vref just below V+/2. You will never get 120 dB CMRR if you use 1% passives in the front-end and you net a 1% DM/CM error that's a 20 dB CMRR. This is why INA's are used with laser-trimmed errors.
 https://www.researchgate.net/profile/Chusak-Thanawattano/publication/261229670_Wearable_wireless_ECG_sensor_with_cross-platform_real-time_monitoring/links/566a430008ae62b05f0296c5/Wearable-wireless-ECG-sensor-with-cross-platform-real-time-monitoring.pdf
--------------------------
 https://www.analog.com/en/resources/analog-dialogue/articles/ecg-front-end-design-simplified.html