Suppose, I have one Tx and one Rx physically separated by the long distance with clock signals CLK1 and CLK2 as shown in fig. (say both of 50MHz). I wish to align them in phases. By that I mean, rising edge of CLK1 and rising edge of CLK2 should match at any instance of time. How to achieve it?
An oscillator at each end that is phase locked to the WWV transmission on 10.0 MHz (as long as both sites can reliably receive that WWV transmission) would accomplish your need. If the two sites are not to far apart the carrier (with the side-bands filtered out) of an am radio between them can be used to provide the reference frequency for your clock frequency synthesizers. With more effort a GPS frequency standard or the carrier frequency of a (receivable by both sites) FM radio station could be used. These methods will result in two separate phase locked frequency standards.