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Altera_Forum's avatar
Altera_Forum
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14 years ago

PLL output square wave distorted

I am testing PLL output from an old Stratix board. The PLL has an onboard 80MHz crystal as input clock. However at > 60 MHz, the PLL output is not as square as I wish with ripple and 50mv u...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

I suggest to think about some basic signal theory relations. TDS5034 has a bandwidth of 350 MHz. To display a 250 MHz square wave different from a sine, you'll need at least 750 MHz bandwidth to see the 3rd harmonics.