Other Parts Discussed in Thread: ADS1294, ADS1293
We are designing a single lead EKG recorder with sensors about 7.5 cm (3 inches) apart. As it is a small system and wireless (nothing is connected to the ground) it is my understanding that the common mode noise/power-line noise would be quite small.
However, we are contemplating the ADS1294 instead of the ADS1291 as the 1294/6/8 seem to be superior in some ways (except for power consumption) see table:
|
ADS1291 |
ADS1294 |
Input-Referred Noise |
8 μVPP |
4 μVPP (150 Hz BW, G = 6) |
Data Rate |
125 SPS to 8 kSPS |
250 SPS to 32 kSPS |
CMRR |
–105 dB |
–115 dB |
Power |
335 μW/channel |
0.75 mW/channel |
But having a closer look at the data rate shows (ADS1291 on top ADS1294 on bottom):
I believe 8kSPS is more than enough for all software analysis/filtering of a single lead EKG, therefore aren´t the data rates actually the same under these conditions?
So the question is: are the Input-Referred Noise and CMRR differences going to be noticeable? Or am I wrong regarding the data rate?
Secondly: Would adding a DRL (driven right leg) electrode help reduce noise even though that electrode would be placed near the other two and not on the right leg, i.e. far away?
Finally: Are there any data converters other than the ADS129x-series I should consider?
Thank you in advance