a pll apparatus and system for generating distributed clocks are disclosed . a synchronizing - edge detector is provided to the pll apparatus in the pll system to detect synchronizing edges of the input and output clock signals having gear relationship for the pll apparatus . the synchronizing - edge detector detects a sample signal the frequency of which is the common divisor of the frequencies of the input and output signal . the pll apparatus may be provided with a detection terminal connected with one of the input terminals of a pre - divider and loop divider for outputting the sample signal . alternatively , the pll system can comprise at least one additional divider coupled to the input and / or output signals of a pll apparatus to generate the sample signal .