Which provides better performance – a clock source with sinewave output, or one with differential square wave outputs?
An important factor in reducing jitter is the slew rate of the input signal. PECL outputs tend toward a square waveform, which, along with their typical 800 mV amplitude, have good slew rates. In addition, PECL is usually used differentially, which improves the slew rate further. This makes PECL a good choice for a clock source.
