pna can do time domain measurement,and can locate the cable default position,I want to know pna how know the distance of the default position in the cable? pna can measure the distance like radar? pls help,thx!

" pna can do time domain measurement,and can locate the cable default position,I want to know pna how know the distance of the default position in the cable? pna can measure the distance like radar? pls help,thx! "

Hi, the time domain transform uses a form of the inverse Fourier transform to convert reflections in the frequency domain to equivalent response in the time domain. If you think about a cable with two bad spots (mismatches) in it, the frequency response (return loss) will show valleys when the two bad spots are 1/2, 3/2 ...wavelength apart (in reflection) and peaks in between. If you convert this to the time domain, you will see two peaks, separated in time. The time spacing is proportional to the inverse of the spacing of the frequency peaks. If we know the velocity of propagation of the cable, we can say what the distance is between the the time domain peaks.

Hi, the time domain transform uses a form of the inverse Fourier transform to convert reflections in the frequency domain to equivalent response in the time domain. If you think about a cable with two bad spots (mismatches) in it, the frequency response (return loss) will show valleys when the two bad spots are 1/2, 3/2 ...wavelength apart (in reflection) and peaks in between.

If you convert this to the time domain, you will see two peaks, separated in time. The time spacing is proportional to the inverse of the spacing of the frequency peaks. If we know the velocity of propagation of the cable, we can say what the distance is between the the time domain peaks.