Datasheet
ADAS1000-3/ADAS1000-4 Data Sheet
Rev. A | Page 26 of 76
ECG INPUTS—ELECTRODES/LEADS
The ADAS1000-3/ADAS1000-4 ECG product consists of three
ECG inputs and a reference drive, RLD (right leg drive). In
a typical 3-lead/vector application, three of the ECG inputs
(ECG3_RA, ECG1_LA, ECG2_LL) are used in addition to the
RLD path.
In a 3-lead system, the ADAS1000-3/ADAS1000-4 can be
arranged to provide Lead I, Lead II, and Lead III data or
electrode data directly via the serial interface at all frame
rates. Note that in 128 kHz data rate, lead data is only available
when configured in analog lead mode as shown in Table 11.
Digital lead mode is not available for this data rate.
Should the user have a need for increased electrode counts, then
there are other products within the ADAS1000 family that may
be suitable. For example, a derived 12-lead (8-electrode) system
can be achieved using one ADAS1000-3 or ADAS1000-4
device ganged together with one ADAS1000-2 slave device
as described in the Gang Mode Operation section. Similarly,
a 12-lead (10-electrode) system can be achieved using one
ADAS1000 or ADAS1000-1 device ganged together with one
ADAS1000-2 slave device as described in the Gang Mode
Operation section. Here, nine ECG electrodes and one RLD
electrode achieve the 10 electrode system, again leaving one
spare ECG channel that could be used for alternate purposes
as suggested previously. In such a system, having nine dedi-
cated electrodes benefits the user by delivering lead information
based on electrode measurements and calculations rather than
deriving leads from other lead measurements.
Table 10 outlines the calculation of the leads (vector) from the
individual electrode measurements when using either the
ADAS1000-3 or ADAS1000-4.
Table 10. Lead Composition
Device Lead Name Composition Equivalent
ADAS1000-3 or ADAS1000-4 I LA – RA
II LL – RA
III LL – LA
aVR
1
RA – 0.5 × (LA + LL) −0.5 × (I + II)
aVL
1
LA – 0.5 × (LL + RA) 0.5 × (I − III)
aVF
1
LL – 0.5 × (LA + RA) 0.5 × (II + III)
1
These augmented leads are not calculated within the ADAS1000-3/ADAS1000-4, but can be derived in the host DSP/microcontroller/FPGA.