Hi,
I'm trying to specify a frequency dependent resistance (an approximation of the skin effect).
I have a parameters include file, and need to specify the frequency within an expression (in curly brackets) as follows:
S3_skin_tu1 = {PI*PWR(S3_r_tu1-SQRT(2*S3_res_tu1/(2*PI*FREQUENCY*u_Cu)),2)}
However, PSpice does not understand 'FREQUENCY' (nor 'FREQ' or anything else I've tried). I've not been able to find anything in the documentation.
Does anyone know of a way to use AC frequency in an expression?
Any suggestions will be gratefully received!
Regards,
Nick
I've found out how to do this. For those who are interested:
I've used an 'E' device (a controlled voltage source) as follows...
E_DEVICE_NAME node1 node2 LAPLACE {I(E_DEVICE_NAME)} = {XFORM expression involving 's'}
where the XFORM is:
rho*length/(PI*PWR(radius,2)-PI*PWR(radius-SQRT(2*rho/(ABS(s)*mu)),2))
rho=resistivity of conductor, radius=radius of conductor, mu=permeability of conductor
The frequency dependent resistor device is between nodes 'node1' and 'node2'. The simulated source voltage is equal to I(E_DEVICE_NAME) (i.e. the current through the device) multiplied by the XFORM where 's' is replaced by j*omega (omega=2*pi*frequency) which evaluates to the resistance required.
Note that here it is important that ABS(s) appear in the XFORM (rather than just 's') otherwise XFORM will be in general complex, and thus the device would have a reactance. Here I want the device to be purely resistive.