General: USB Frequency Range

What frequency range is occupied by a 3 kHz USB signal with the displayed carrier frequency set to 14.347 MHz?

A. 14.347 to 14.647 MHz
B. 14.347 to 14.350 MHz
C. 14.344 to 14.347 MHz
D. 14.3455 to 14.3485 MHz

This is really just a question of simple addition, so don’t let all the numbers there throw you for a loop.

Remember that USB, or Upper Side Band, puts the actual signal on the” upper” portion of the signal.  This means that the 3kHz signal is above the “displayed carrier frequency” (which really makes this question a bit misleading, since single sideband really doesn’t have a “carrier” signal….)

So, do the math.  Add the 3kHz, or .003 MHz (remember your metric prefixes!), to 14.347, and you get B. 14.347 to 14.350 MHz.


1 thought on “General: USB Frequency Range”

  1. I kinda disagree with the answer considering the way it was asked. The “frequency range” of a 3 KHz at 14.347 MHz is just 14.350 MHz.The question assumes you know the range of the sideband audio signal’s low end. The rangw would have been 14.3473 MHz to 14.350 MHz if the question had asked what the frequency range is of a 300 Hz to 3 KHz USB signal. Not nitpicking. Just adding my 1.73 cents worth. 😀


Leave a Comment