2 ms·
"One second per 300 billion years" is really a statement about the bandwidth of the signal that the clock generates, translated for lay readers. We don't know w
by klodolph 5y ago
"One second per 300 billion years" is really a statement about the bandwidth of the signal that the clock generates, translated for lay readers. We don't know what the actual bandwidth of the signal is, since it's not stated in the article. Bandwidth is measured in Hz.
In order to measure the bandwidth of the signal (and how accurate the clock is), you have to measure the clock over a period of time. The shorter that period of time, the worse your measurement will be. The smaller the bandwidth, the more time you need to measure it.
Note that a signal with 5 Hz bandwidth and 5 Hz center frequency would make a very terrible clock, while a signal with 5 Hz bandwidth and 5 GHz center frequency would make a very nice clock. The bandwidth is the same in both cases, and the amount of time required to measure bandwidth is the same, but they make very different clocks.
- oshiar53-0 5y agoDoes this mean that 0 Hz bandwidth leads to the ideal clock?
- rcxdude 5y agoYes, since that corresponds to a sine wave with fixed frequency extending forwards and backwards in time infinitely. (NB: it does depend on how you measure it. To truely get this you would also need to measure the clock output for all time).
- pastage 5y agoWhat does center bandwidth mean here? My understanding of this from the domain of GPS time, has always been; you can have a good clock (GPS is slow, accurate over a long time) or a good ocillator (fast, inaccurate over along time). But together you can have both.
- klodolph 5y agoDo you mean “center frequency?” A signal that goes from 9 Hz to 11 Hz has a center frequency of 10 Hz and a bandwidth of 2 Hz.
- deleted 5y ago[deleted]