Patent ID: 7424649

Claim:
A latching method comprising the steps of: latching a first signal in response to a first portion of a second signal to generate a first latch signal, said first portion being one of a rising edge and a falling edge of the second signal, said first and second signals being periodic signals; latching said first signal in response to a second portion of said second signal to generate a second latch signal, said second portion being the other of the rising edge and the falling edge of the second signal; and selecting one of said first and second latch signals as a latch signal output, wherein said step of selecting includes: detecting a latching position error in each of said first latch signal and said second latch signal to generate a latch error signal, said step of detecting including detecting a latch error in said first latch signal to generate a first latch error signal, and detecting a latch error in said second latch signal to generate a second latch error signal, and selecting one of said first and second latch signals based on said latch error signal, wherein each of said step of detecting a latch error in said first latch signal and said step of detecting a latch error in said second latch signal includes: receiving an associated latch signal from among said first and second latch signals and using said second signal to generate a latch state signal indicative of the length from a predetermined reference position of said second signal to said latching position of said associated latch signal; and comparing said latch state signal for a first periodic portion of said first signal with said latch state signal for a second periodic portion adjacent to said first periodic portion of said first signal to generate a latch error signal in said associated latch signal in accordance with a result of the comparison.