Odd question about A/C digital clocks

[HOOfan_1]

DO A/C digital clocks at all depend on current frequency to keep time?

I have a Sony Dream Machine alarm clock that keeps perfectly normal time when hooked up to the mains.

I have had no power for the past 75 hours now due to Irene, but I have the clock hooked up to a generator and it seems to be going much faster.

In an 8 hour night it was 6 minutes faster than my battery clocks and watch.

I reset the time last night at 11:20PM and now at 7:11PM today it is saying 7:26 PM, so over 20 hours it has gone forward 15 minutes.

The only thing I can think of is that perhaps the generator's frequency is not the normal 60hz of US power.

[Hondacity]

some clocks do that, its weird. and yeah i agree with the 60hz variation causing oscillator to go bad. sorry no hard info but i've had that issues from imported digital clocks.

[Zero82z]

It wouldn't make a lot of sense to me if it did use the mains frequency as a reference. It's not like the frequency is always going to be constant. Even small variations would be a big deal for timekeeping accuracy.