Looks like “one times 10 to the ninth” which equals 1000 megahertz (1 GHz).  1 Mhz would be “one times 10 to the sixth.”  It is scientific notation as used in mathematics.  When electronic calculators came into use they came up with a new notation system for scientific notation which was more compatible with calculator.  That’s where the 1E9 comes from (actually, the “E” stands for Engineering notation which is expressed in multiples of three – i.e., -12, -9, -6, -3, 0, 3, 6, 9, 12, which engineers use.  They relate to the more usually used units, Kilo, Mega, Micro, etc.) In the old days it would have been written 1 X 10^9, and actually, that is a change from the way you would write it by hand.  With computer keyboards – the method is to indicate a superscript 9 (raised to the power of 9) is by preceding the number with a carrot symbol.

Roger, KL7Q

 

 

Can anyone help with explanation of  following terminology for frequency:-
example 1e9
is this 1Mhz?
73 Laurie.