You can access the distribution details by navigating to My Print Books(POD) > Distribution
Book signal tells what signal is . It s oscillation of matter particles atoms in space . They have north south polarity as discussed in the book. Signal is same as electric current in the air. It is produced from electricity as well as heat and fire. All matter generates signal or small electric current on combustion. Similarly electric current when leaks in to air it is signal. It can be picked up by the oscillator circuit as discussed.