| back to text |
|
|
Using Mike Chin's software, written in CPM-- the standard operatuing system at the time for
S-100 bus computers, the cycle histogram data was resampled to produce 64 increments of phase
rather than 100, and a fast-Fourier-transform algorithm was applied. At low stimulus intensities,
the fundamental (linear) component consistently was the largest by far. The unit of amplitude
for that component was 1.0 spikes per increment of phase. Dividing the value of the
amplitude (X spikes per increment of phase) by the time represented by a single phase increment
(the total sampling time divided by 64) yields the peak instantaneous spike rate in the linear
response component (in our discrete representation of time, an instant is defined to be the time
in one 64th of a stimulus cycle). Dividing that peak instantaneous spike rate by the peak stimulus
intensity yields the linear transfer ratio, or transducer gain, of the unit for the frequency
at hand. For each saccular unit with a substantial resting spike rate (most of the units we have
observed), at low stimulus levels the computed transducer gain was independent of stimulus level.
Here are transducer gains computed for unit 11038105 at low stimulus levels for each of six frequencies.
The 3-dB bandwidth of the unit is about 40-50 Hz, making its filter quality factor (Q) about 2.
most recently updated 07/20/07