Index: impedance.c
===================================================================
--- impedance.c	(revision 31757)
+++ impedance.c	(revision 31758)
@@ -27,18 +27,18 @@
 #include "config.h"
 #include <math.h>
 
-#define TOM(x) (RND_COORD_TO_MM(x) / 1000.0)
+#define TOM(x) RND_COORD_TO_MM(x)
 #define SQR(x) ((x)*(x))
 #define N0 377
 
-double pcb_impedance_microstrip(rnd_coord_t trace_thick, rnd_coord_t trace_height, rnd_coord_t subst_height, double dielect)
+double pcb_impedance_microstrip(rnd_coord_t trace_width, rnd_coord_t trace_height, rnd_coord_t subst_height, double dielect)
 {
-	double w = TOM(trace_thick), t = TOM(trace_height), h = TOM(subst_height), Er = dielect;
+	double w = TOM(trace_width), t = TOM(trace_height), h = TOM(subst_height), Er = dielect;
 	double weff, x1, x2;
 
 	weff = w + (t/M_PI) * log(4*M_E / sqrt(SQR(t/h)+SQR(t/(w*M_PI+1.1*t*M_PI)))) * (Er+1)/(2*Er);
 	x1 = 4 * ((14*Er+8)/(11*Er)) * (h/weff);
-	x2 = sqrt(16 * SQR(h/weff) * SQR((14*Er+8)/(11*Er)) + ((Er+1)/(2*Er))*M_PI);
+	x2 = sqrt(16 * SQR(h/weff) * SQR((14*Er+8)/(11*Er)) + ((Er+1)/(2*Er))*M_PI*M_PI);
 	return N0 / (2*M_PI * sqrt(2) * sqrt(Er+1)) * log(1+4*(h/weff)*(x1+x2));
 }
 
Index: impedance.h
===================================================================
--- impedance.h	(revision 31757)
+++ impedance.h	(revision 31758)
@@ -1,2 +1,2 @@
-double pcb_impedance_microstrip(rnd_coord_t trace_thick, rnd_coord_t trace_height, rnd_coord_t subst_height, double dielect);
+double pcb_impedance_microstrip(rnd_coord_t trace_width, rnd_coord_t trace_height, rnd_coord_t subst_height, double dielect);