Leaky Coaxial Cable radiation

hi,

I want to discus the leaky coaxial cable intruder detection system presented in the attach file. I am confused bout the detection method described in this document. At page 14 it says

" It is necessary to address the issue of sampling rate. The sampling rate used to
capture the waveforms is 3 KHz. According to (10) this is way below the required
sampling rate in order to monitor the 150 MHz signal. While this is true, our detection
method does not need accurate monitoring and reconstruction of the signal, and, instead,
designed so that it relies on aliasing to detect the change in amplitude. We do not need to
sample at 300 MHz (10) in order to detect the change in magnitude. Our signal of
interests is the modulated carrier frequency created by the movement of the
intruder/extruder and therefore 3 KHz is enough to catch the set of samples at which the
amplitude has changed. The use of 150 MHz was simply because the tLCX leaked
signals of the frequency the most."

How FM modulation is occurred there?

Where do you see FM involved? It's not mentioned in the report at all.

Sorry i miss-typed . it "modulated carrier frequency"

"modulated carrier frequency created by the movement of the intruder" , what does it mean?

It essentially means AM by variation of the reflected 150 MHz signal.

Thanks for reply.

The receiving cable is directly connected to the ADC module. Can i place a super-hetrodyne or direct conversion receiver at the receiver side?