# Rate and Frequency, Are they the same?

1. Mar 29, 2012

### bmed90

In my mind rate can be thought of as how often something occurs per time (in time domain)

To my knowledge frequency is cycles/time

Can these two words be thought of as different words with the same meaning?

2. Mar 29, 2012

### huntoon

I think rate does not include cycle in its meaning, whereas frequency does.
Frequency implies an oscillation but rate doesn't.

rate can be graphed as a flat line 70 miles per hour for 1 hr.

frequency is graphed like a sin, where you have highs and low to mark off discrete events that are counted per time.

3. Mar 29, 2012

### bmed90

Hmm so, perhaps they are not the same because rate can be a constant value over time whereas frequency is a value that is always changing?

4. Mar 29, 2012

### huntoon

rate:
A way of comparing two quantities.

frequency:
The number of times a value occurs in some time interval.

source: http://www.mathpropress.com/glossary/glossary.html [Broken]

Last edited by a moderator: May 5, 2017
5. Apr 1, 2012

### litup

An example of that would be radar: it can be an RF beam running at 10 gigahertz, say, and it has to by definition, send out pulses, so say it has a pulse width of 1 nanosecond and sends that out 100 times per second, that would then be a pulse recurrence frequency of 100 hertz. That is PRF. That is the rate the pulse is sent out. In between the pulses, the receiver is turned on to listen for returns. At 100 pulses per second, since the speed of light is about 186,000 miles per second, 1/100th of that would be 1860 miles but you have to cut that in half because the signal has to go out and come back so in this case the range of the radar would be 930 miles.

6. Apr 1, 2012

### PietKuip

Radioactive decay can occur at a certain rate, but it has no frequency. There is no periodicity, the times between decays are random.