Interesting choice of example. The 9V battery gets its rectangular shape from being a stack of 6 1.5V batteries in series. Yet, claiming that the battery isn'

Interesting choice of example. The 9V battery gets its rectangular shape from being a stack of 6 1.5V batteries in series. Yet, claiming that the battery isn't 9V but 6 x 1.5V would be considered needless pedantry. Now, let's say that I have a cuckoo clock that chimes once per hour. This is a rate of ~ 278 μHz. Now, imagine that I buy 3600 of these clock and set them to offset them by 1 second each. I now have 3600 x 278 μHz signals. However, I also have 1 clock going off every second. Thus, the frequency rate for the entire system is 1 Hz, even though the individual components have a much slower rate. Now, let's say that I didn't do such a great job in aligning the signals of the clocks. Some are 2 seconds apart while others are mere milliseconds apart. From a Fourier transform perspective, there's now multiple signals with multiple frequencies occurring. However, if I average over a long time period, I'm still getting 3600 events per hour, or 1 event per second. The signal may not be a perfect sine curve, but, barring a pathological timing, the strongest Fourier component is going to be the 1Hz signal. Thus, 1Hz would be a reasonable way to describe the cuckoo bird rate of the system.