The sensitivity of a quartz crystal's resonant frequency to changes in the external load capacitance connected across its pins. It is expressed in parts per million per picofarad (ppm/pF). High pullability is desirable in voltage-controlled crystal oscillators (VCXOs) where the frequency must be tuned, but undesirable in fixed clocks where stability is paramount.
We need a crystal with high pullability so the PLL can lock onto the incoming video sync signal.
Related terms
Quartz crystal
A precisely cut piece of piezoelectric quartz used to generate a highly stable oscillating frequency.
VCO
A voltage-controlled oscillator is a circuit that changes its output frequency based on a DC input voltage.
PLL
A phase-locked loop circuit that synchronizes an output oscillator with a reference signal.