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ADAS1000 Questions

Question asked by alex.looi@welchallyn.com on Jan 25, 2015
Latest reply on Feb 22, 2016 by CatherineR

Hi,

 

I need some advice on ADAS1000.

 

1) In the electrical specs, a lot of the parameter are pointing to note 1 and 2.

Note 1 says" Guaranteed by characterization, not production tested"

Note 2 says "Guaranteed by design, not production tested"

I don't really understand what the notes mean. Do they mean that the specs are not tested but all are theoretical specs ?

 

 

2) The datasheet says that the ADC is a 14 bit SAR.

But in the electrical specs page 5, it says that the resolution can be 19, 18, and 16 bits.

Also, the respiratory ADC is 24 bits. How are these higher resolution being achieved ?

 

 

3) For Digital Lead Mode, for the V1 and V2 signal, the output of the ADC is already V1 - WCT.

Why does the digital domain calculation still needs to minus WCT again ? Refer to page 31 Figure 59 of the datasheet,

at the bottom of the page, it says Word 4 is V1' = V1 - WCT(4). And note 4 says that WCT is digitally calculated

based on the measurement of RA, LA, LL. Why is this required ? The WCT is already connected to

the -ve input of the amplifier for V1 and V2.

 

 

4) Page 39 of the datasheet, Figure 69 Simplieid Respiration Block Diagram. This diagram shows the use of internal respiration circuit.

Why is the mux switch (the one connecting the top 100pF to the +ve lead of the amplifier) at the top not closed ?

 

 

5) Page 42 Pacer Artiface Detection. The detectable pacer specs is of width 100us to 2ms, and amplitude 400uV to 1000mV.

What is the tolerance ? Eg, for min detection width of 100us, is it guaranteed ? Or it actually has a tolerance of eg 10% ?

i.e. the min may be 110us?

 

 

6) Page 42 Pacer Artiface Detection. The datasheet specifically says:

"The ADAS1000 pace algorithm can operate with the ac lead-off and respiration impedance measurement circuitry enabled.

What about DC leads off ? Does it mean that I cannot use DC lead-off if I want to use the pace algorithm ?

 

 

7) What is the probability that the Pacer detection algorithm mistake Q waves and S waves for a pacer pulse, since both waves are

narrow and may fit into the criteria of the pacer detection parameters ? Especially Q waves, since it is a short pulse duration that starts

from the baseline (PR segment).

 

Thanks.

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