Is there a way to know the ppm of the clock oscillator in a smartphone?
For example, in the Android documentation on System Clock, there is a function elapsedRealtimeNanos, which guarantees a monotonic clock. However, I would like to know how much drift may occur when compared to an atomic clock. Even using NTP won't reveal any intuition on what is an expected amount of drift given the current hardware in phones.
If it's possible, can you share where you found the ppm information and how to calculate the error (in seconds) after x seconds have passed?
Best Answer
ppm error on the oscillator may vary from one model to another. Here are some ballpark numbers.
Calculating error envelope from ppm is easy. 1 ppm is 1 microsecond. In 1 second, a 20 ppm clock can gain or loose 20 μs in the worst case.
On a smart phone, can you access the GPS time? It originates from atomic clocks. GPS time has good long term stability. Just an $0.02 thought.
Another somewhat related thread.