Amateur radio + frequency measurements

[JamesGoh]

For an exam I am studying for, I have to understand the effect of measurement tolerance, calibration accuracy and time-related drift on frequency measurements.

Im aware that the time-related drift is due to the oscillator frequency becoming less accurate (due to continuous crystal vibration), however I am not sure about measurement tolerance and calibration accuracy.

Does measurement tolerance refer to a tolerated frequency range the ideal frequency measurement falls around ? (e.g say if I wanted to get an ideal reading of 9Hz and instead I get 8Hz, I would take 8Hz)

Im guessing that calibration accuracy would refer to how well the equipment has been calibrated to generate or measure a frequency (e.g. how well a crystal has been carved to generate a resonant frequency) ?

thanks in advance

 

[anorlunda]

HAMs @Baluncore, @berkeman ping

 

[berkeman]

For an exam I am studying for, I have to understand the effect of measurement tolerance, calibration accuracy and time-related drift on frequency measurements.

Im aware that the time-related drift is due to the oscillator frequency becoming less accurate (due to continuous crystal vibration), however I am not sure about measurement tolerance and calibration accuracy.

Does measurement tolerance refer to a tolerated frequency range the ideal frequency measurement falls around ? (e.g say if I wanted to get an ideal reading of 9Hz and instead I get 8Hz, I would take 8Hz)

Im guessing that calibration accuracy would refer to how well the equipment has been calibrated to generate or measure a frequency (e.g. how well a crystal has been carved to generate a resonant frequency) ?

thanks in advance

There is a lot of information available about initial crystal oscillator accuracy (over temperature, etc.), and the effects of aging. The wikipedia article is pretty good, and this is a good survey paper:

https://www.semtech.com/uploads/documents/xo_precision_std.pdf