Reference Section • 107
Chapter 5
Noise
• Sources of instrument noise in the MultiClamp 700A.
• See also Feedback Resistor, Filters, Grounding and Hum, Headstage, Power
Supply, Series Resistance Compensation.
Measurement of Noise
Noise is reported in two different ways in this manual.
• Peak-to-peak (p-p) noise. This measure finds favor because it is easily estimated
from an oscilloscope and its meaning is intuitively obvious. A disadvantage is that
it is very insensitive to structure in the noise (e.g. different frequency components).
For this reason, it is most commonly used for quantifying “white” noise. (See
Chapter 5,
FILTERS.)
• Root-mean-square (rms) noise. This is essentially the “standard deviation” of the
noise and can be calculated using a computer or an electronic circuit designed for
this purpose. For white noise, the rms noise is approximately one-sixth the peak-
to-peak noise. The MultiClamp Commander displays the rms noise on the
Membrane Current signal in V-Clamp mode after checking the Irms checkbox
below the meters. The measurement is made with a bandwidth of 30 Hz to 5 kHz
(4-pole Butterworth filter). See the table on page 81 in the Feedback Resistor
section for noise measurements using the CV-7A headstage.
When reporting measured noise, the bandwidth (i.e. filter cutoff frequency) must
always be stated.
To Next Page
Loading...
Need help?
General
