Spread spectrum time domain reflectometry. How inject frequencies?

[cupoftea]

Hi,
When you’re doing Spread Spectrum Time domain reflectometry, and you want to inject frequencies from 93kHz to 24MHz into a cable (to see where it has a fault)…..what do you use to inject those frequencies into the cable?

It could be electrical cable, data cable, coaxial cable or shielded power distribution cable.
Why is the range of SSTDR longer in “ shielded power distribution cable”.

 

[BradtheRad]

From what I understand a bat squeaks once while simultaneously disconnecting its auditory nerves so its ears are not overloaded by the noise burst. Then it connects its ears to listen for an echo.

Radar works the same way.

In similar fashion I imagine you send a single voltage spike through low impedance switch. Then immediately go to high impedance in order to detect a reflected pulse at a sensitive receiver.

 

[FvM]

Are you specifically asking about connecting the SSTDR measurement to a live wire? For power cables, you'll use a similar circuit as for power line communication, a kind of high-pass that can stand the supply voltage.

Why is the range of SSTDR longer in “ shielded power distribution cable”.

You'll look for loss factor at MHz frequencies depending on the cable configuration. An unshielded cable is dissipating or radiating RF signals to the vicinity after a short distance.