“…The first is to change the frequency interval slightly, for example, to increase 2 KHz or ôf=2 KHz in our condition, then t r must be increased slightly i. e. by ô t r to flatten the phase trace. Thereafter, n may be calculated from the following equation n=if(f+ôf) 6 tr/ôf (2) Due to the measurement error and the temperature effect, the calculated n may not be a whole number, then it is rounded to the nearest number. The second method is to decrease Lf until the phase differences between neighboring measurement points become less than 2, for example, let the total measurement bandwidth equal 10 MHz or f=12.5…”