Biomedical Engineering Reference
In-Depth Information
TaBlE 7.3:
SNR calculations
NEURoN 1
NEURoN 2
Noise
V
rms
(µV)
8.24
8.24
Neuron
V
pp
(µV)
71.13
79.33
SNR (dB)
18.72
19.67
For all of the neural recordings presented here, the system power consumption for the Pico
Remote is quantified in Table
7.4
. The Pico remote consumes around 130 mW, whereas bin count-
ing, on a 3.7-V, 150 mA h LiON battery, would provide about 4.25 h of operation.
Now that the initial goal of bringing actual neural data from a live subject over the wireless
link to a PC has been achieved, we can move forward in processing the data on the Pico remote by
applying our spike counting algorithm. There are still additional tests that have to be completed, such
as, comparing in a parallel test, raw signal data and spike counts with a commercial system, such as
those from TDT Systems.
To ensure data integrity over the wireless link, we have created specifications for a robust com-
munications protocol that utilizes packet acknowledgements and resends. Any data sent over the
wireless network will be acknowledged by the receiving device. If the sending device does not receive
an acknowledgement in a few milliseconds, the data are resent. A new version of the Nordic part
allows for data resends in hardware reducing power and firmware complexity. Once the latest Nordic
parts and the protocol are implemented, we expect data loss to be very close to zero.
FIgURE 7.13:
Noise introduced by the Pico system.
