Editing Heaviside condition (section)

===Characteristic impedance===
The [[characteristic impedance]] of a lossy transmission line is given by
:<math>Z_0=\sqrt{\frac{R+j\omega L}{G+j\omega C}}</math>
In general, it is not possible to [[impedance matching|impedance match]] this transmission line at all frequencies with any finite network of discrete [[electrical element|elements]] because such networks are [[rational function]]s of jω, but in general the expression for characteristic impedance is complex due to the square root term.<ref>Schroeder, p. 226</ref>  However, for a line which meets the Heaviside condition, there is a common factor in the fraction which cancels out the frequency dependent terms leaving,
:<math>Z_0=\sqrt{\frac{L}{C}},</math>
which is a real number, and independent of frequency if L/C is independent of frequency. The line can therefore be impedance-matched with just a resistor at either end. This expression for <math>\scriptstyle Z_0 = \sqrt{L/C}</math> is the same as for a lossless line (<math style="vertical-align:-15%;">\scriptstyle R = 0,\  G = 0</math>) with the same ''L'' and ''C'', although the attenuation (due to ''R'' and ''G'') is of course still present.