## Measurement of electronic distances.

When Python is the interpreter, what is a good
design for the interface to the basic NEURON
concepts.

Moderator: hines

gary
Posts: 6
Joined: Wed Jan 23, 2013 5:19 pm

### Measurement of electronic distances.

Apologies in advance for another obtuse question.

I enjoyed working through the electronic analysis tutorial at http://www.neuron.yale.edu/neuron/stati ... zclass.htm using the NEURON GUI. Returning to my Python code, I am attempting to perform a similar analysis however I cannot see an obvious way to return the value of `attenuation' or `log(attenuation)'. Looking at http://www.neuron.yale.edu/neuron/stati ... html#ratio , the impedance class' function `ratio' is the closest thing I can find. Or is the attenuation measurement not available for the programmer?
ted
Posts: 5784
Joined: Wed May 18, 2005 4:50 pm
Location: Yale University School of Medicine
Contact:

### Re: Measurement of electronic distances.

The voltage transfer ratio is
voltage downstream / voltage upstream
and is always <= 1.

Voltage attenuation is simply 1 / voltage transfer ratio, so that a bigger number means more attenuation (makes sense, right?).
gary
Posts: 6
Joined: Wed Jan 23, 2013 5:19 pm

### Re: Measurement of electronic distances.

Thanks for an incredibly swift answer!
ted wrote:(makes sense, right?)
I *think* so. You can score my responses to your reply as to whether or not I really do understand!
ted wrote:The voltage transfer ratio is voltage downstream / voltage upstream and is always <= 1.
If this refers to Impedance.ratio(x) - I interpret this as downstream voltage recorded at the CAS at location x divided by the size of the upstream voltage source located according to Impedance.loc() after calculation with Impedance.compute(freq, flag). Since voltages can't `grow', this means its value must be <=1.
ted wrote:Voltage attenuation is simply 1 / voltage transfer ratio, so that a bigger number means more attenuation (makes sense, right?).
Or: log_e(Attenuation) = -log_e(Ratio) = my measurement of electronic distance in units of nepers?
ted