At a recent checkup, I was shocked: Even though I was eating foods rich in saturated fat and a seemingly more indulgent diet, my total cholesterol was down 10 points, my bad LDL cholesterol was stellar, and my good HDL was the highest it's ever been.
As the frequency of the signal to be measured increases to approach the frequency of the source frequency, measurement error increases. To improve the accuracy of the frequency measurement for higher unknown frequency, we can use this second measurement method, count number of pulses in known time.
when thinking of a photon as a particle, frequency is a measure of how many of these particles pass a given point ni a given amount of time. This isn't correct. The frequency of light corresponds to the rate of oscillation of the E (and B) fields. The measure of how many of these particles pass a given point is the light's intensity. These were illustrated in the photoelectric effect.