ECG Acquisition in a Computer - ECG Acquisition and Automated Remote Processing - page 87

The algorithm steps for computing the BER and PE are given in end of Chapter
Appendix 4 . If the values are permissible, then the extracted bit streams are
extracted and a new file with time-stamped ECG samples was formed.
In the next stage, the application software will compute the wave durations and
intervals from the collected ECG data over the wireless link. The processing steps
and algorithms are described in Chap. 2 . The following ECG time plane features
are computed:
(1) RR duration; (2) QRS interval; (3) QT interval; (4) P-wave duration; (5)
T-wave duration; (6) QRS amplitude; (7) P-wave amplitude; (8) T-wave ampli-
tude. The extracted wave durations and features are compared with the corre-
sponding ones at the transmit end. Table 4.1 includes the variance figures
computed from some of the leads transmitted using the wireless link, computed
over 5 beats of ECG data.
Figure 4.13 shows different fiducial points from received data.
A significant improvement in the 'quality of transmission' can be achieved by
adopting the principle of 'burst error correction (BEC)'. In BEC principle, 'error
correction by retransmission' is adopted where the transmitter waits for automatic
repeat request (ARQ) signal from the receiver before transmitting the next packet.
If no ARQ is received within a predefined 'timeout' period, the next packet is
delivered. This 'stop and wait' ARQ technique could be implemented using a
modification of the firmware of the PES MCU.
4.4 Conclusion
Tele-ECG is an emerging area if remote healthcare applications. In this chapter, a
brief review of ECG transmission techniques for remote-end acquisition and
computerized analysis is described. Our experimentation on ECG transmission
using a wire and wireless media for short range of communication is illustrated
with a few results.