Hi

I get same digital numbers as Table: adas1000_data_format.png .

As I understand, we have 24-bit digital data at every led. How do I convert the 24 digital bits to the ECG voltage?

Hi

I get same digital numbers as Table: adas1000_data_format.png .

As I understand, we have 24-bit digital data at every led. How do I convert the 24 digital bits to the ECG voltage?

Hello Benjamin,

Thanks for your message.

You are correct, the digital data result is a 24-bit word (excluding the address bits) for each channel.

To convert the digital result into corresponding voltage, determine first which operating mode you are in, e.g. Electrode mode, Digital Lead mode or Analog Lead Mode, then apply the relevant equation shown in TAble 41 (page 65) of datasheet (copied here...)

I've also attached an example of the calculations across each mode. In these example calculations, I used a fixed GAIN = 1.4, but similarly, other gain settings could be used (and excel sheet modified accordingly). I hope this helps...

best regards,

Catherine.

Hello again !!

Thanks for your reply. The documents that you had attached helped me a lot.

I have another question about respiration digital conversion.

According to the data sheet: Respiration magnitude applies that, 2 x Vreff x (2^24-1)/(1.6468 x respiration gain) .

Can you explain how do you put the values into the equation?

Can you also explain how to calculate the phase of respiration ?

You might as well attach excel document like before.

Thank you again for your help .

Hi Benjamin,

Table 28 of the datasheet shows the Respiration Control register.

Here is where you can configure the gain. You can configre the gain to between 1 and 10. This gain is applied in the measurement path.

The voltage reference value is 1.8V. For standalone mode connect REFOUT to REFIN. There should be a 10uF and 0.1uF bypass capacitors to GND at this node.

Respiration performance is heavily dependent on the amount of impedance and capacitance load associated with the cable, patient and respiration path.

External software processing is needed to extract the envelope and perform the peak detection needed to establish breathing.

Regards,

Padraic

Hi Benjamin,

I was in contact with one of our design engineers in relation to this becuase what you pointed out is correct. The next version of the datasheet will need be updated to include the correct information. Thanks for pointing this out to us.

The correct LSB size is fact 4 x (Vref/(1.6468 x RESP gain)) /(2^24 – 1))

Regards,

Padraic

Hello Benjamin,

Thanks for your message.

You are correct, the digital data result is a 24-bit word (excluding the address bits) for each channel.

To convert the digital result into corresponding voltage, determine first which operating mode you are in, e.g. Electrode mode, Digital Lead mode or Analog Lead Mode, then apply the relevant equation shown in TAble 41 (page 65) of datasheet (copied here...)

I've also attached an example of the calculations across each mode. In these example calculations, I used a fixed GAIN = 1.4, but similarly, other gain settings could be used (and excel sheet modified accordingly). I hope this helps...

best regards,

Catherine.