According to Agilent the rule of thumb is f(bw) = 5 * f(clk) to get the 5th harmonic.
Nope. 5 * f(clk) is only the second harmonic.
f(clk) is the base frequency
3*f(clk) is the first harmonic
5*f(clk) is the second harmonic
7*f(clk) is the third harmonic
etc.
Sorry,it doesn't work that way.
There is no such thing as a first harmonic.
If there was,it would be the fundamental ----in this case,f(clk)
The 2nd harmonic is 2f(clk)
The 3rd harmonic is 3f(clk)
The 4th harmonic is 4f(clk)
The 5th harmonic is 5f(clk),& so on.
Just because a square wave only has odd harmonics,you don't get to change the designations of harmonics.
Yes,in this case 3f(clk) is the first harmonic
you are interested in,but it is still the
3rd harmonic of the fundamental.
heatbreak is correct,as he is using the correct terminology.