/diy/ - Do It Yourself

>>1687888
>tuning tank circuit Q of 50
seems iffy, especially if tunable over a 20% range
>what did they mean by this
broadcast stations are interleaved to prevent interference from anomalous propagation and to protect stations near one another from stomping on each other's sidebands and causing that groovy frequency-inverted sound, which is important in a crowded radio market like NYC or LA
>90° phase shift
assume the VCO is a square wave oscillator and that the PLL input signal has been squared off. now NAND them and filter to get a control voltage, which is at a steady 3/4 of max when locked, and rises and falls proportionally to the actual offset. if the VCO drifts a little slow relative to signal, the control voltage will rise slightly and the VCO will speed up slightly, thus taking up the slack and restoring the phase relationship, and vice versa. thus the PLL follows the phase of the input signal and can self-correct for (theoretically) up to ±90° of input shift. in practice the phase difference between any two cycles is much less than 1° even for broadcast FM. to maintain 0° or 180° offsets, you need to know and care which rising edge came first to know which way to pull the VCO, implyign 2 control loops and crossover distortion

>>1687902
you sure can