OK Becuase I am not an electronics buff lets say I were to do it in software how would I find the sample rate of the system? I figured that the gear spins and the sensor sends out a pulse based on the gear speed. Can I not just alter the frequency of that pulse to change the speed?
There is a lot of good advice in the comments above so I'll just deal with the questions in this comment. Basically, your sensor does exactly what you think, it puts out a string of pulses based on the speed that its input shaft is turning. The device that it is fed into uses the frequency of that string of pulses to determine the rate at which some shaft is turning by multiplying that frequency by some constant. Then the rate is most likely used in a display of some sort or to control the speed of something else or both.
So, depending on what you want to accomplish by changing the frequency of the sensor pulse you will have to do different things. If, for example, you want the device to think the measured shaft is turning more slowly than it is, then you will have to reduce the frequency and if the opposite is your goal, you'll have to increase the frequency. You'll have to give us a bigger clue.