Method of reacquiring clock synchronization on a non-tracking helical scan tape device

A method for reacquiring synchronization of a clock synchronization signal with a data signal in a non-tracking storage device, said non-tracking storage device comprising a read channel, said read channel comprising a read head which generates a data signal based on detection of data from a storage medium in said non-tracking storage device, a phase locked loop (PLL) which receives one of either a reference frequency or said data signal and generates said clock synchronization signal locked to said one of either said reference frequency or said data signal, and a packet reconstructor which reconstructs data packets from said data signal synchronized with said clock synchronization signal, said method comprising:

• switching said PLL to receive said data signal;
• monitoring a packet error status associated with each of a respective one of a predetermined number of a plurality of packets reconstructed from said read signal, said packet error status indicative of whether or not an error was detected in said reconstructed packet associated with said packet error status;
• detecting an unacceptable read quality condition, said unacceptable read quality condition based on the number of said plurality of packets in which an error was detected;
• and
• upon detection of said unacceptable read quality condition:
• switching said PLL to receive said reference frequency;
• locking said clock synchronization signal to said reference frequency;
• and
• repeating said method.