A PLL Is Set Up So That Its VCO Free-Runs

Multiple Choice

A PLL is set up so that its VCO free-runs at 8.9 MHz. The VCO does not change frequency unless its input is within plus or minus 75 kHz of 8.9 MHz. After it does lock, the input frequency can be adjusted within plus or minus 120 kHz of 8.9 MHz without having the PLL start to free-run again. The tracking range of the PLL is:

A) 240 kHz
B) 75 kHz
C) 120 kHz
D) 150 kHz