IEEE-1546254 (pdf) A three-dimensional neural recording microsystem with implantable data compression circuitry
- quite a bit of engineering in this one!
- 256 site
- spike detection ASIC which transmits a parameterized version of the threshold crossings.
- Only consumes 5.4mW total. wow.
- outgoing bandwidth 2.5 Mb/sec.
- Only allows spike detection on 32 of these sites
- The mux is also limited to common groups to minimize consumed space.
- 5 bit spike detection ADC.
- 12.6uV RMS noise.
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- Unidirectional link -- sets threshold automatically.
- 8:1 channel mux changes on both positive and negative clocks, which prevents clock transitions in the middle of the sampling window.
- Measure crosstalk 6% or less -- really?
- Vibert [16] evaluated neural spike separation baseed on eight parameters and concluded that using three parameters, Vmax (the maximum positive spike amplitude), Vmin (the minimum negative spike amplitude) and T (the time between Vmax and Vmin) not only adequately sorted spikes but was superior to separation using more parameters. Other parameters were found to be correlated with Vmax, Vmin, and T, whereas Vmax Vmin and T were uncorrelated.
____References____
Olsson, R.H., III and Wise, K.D. A three-dimensional neural recording microsystem with implantable data compression circuitry Solid-State Circuits, IEEE Journal of 40 12 2796 - 2804 (2005) |