The name is absent

107

to voltage noise in the photoreceptor through the membrane resistance. The output voltage
variance is given by:

^vuc = R²_mio                                  (5.21)

In the coupled rod network, current fluctuations in a rod are distributed through the
network according to the impulse response.

∞ ∞

^υl = ∑ ∑ ⅛                    (5.22)

TTl=-OO Tl=-OO

where ‰,_n is the steady-state impulse response function of the rod network (as in figure
5.5).

For a hypothetical current noise of unit variance, the output variances and standard de-
viations for the uncoupled and coupled cases are:

^vUC - R-m - 0∙09

^f^UC “ R^jτn ~ 0∙3

υ²_c = 0.02

υ_c = 0.15

Because of the signal averaging due to coupling, the baseline noise of the coupled net-
work is half the noise of the hypothetical uncoupled network. The signal-to-noise ratio is the
output amplitude divided by the noise standard deviation, so with whole field stimuli, the

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