Results of the Design

 

The necessary time-bound was that all computation be done during the sampling interval or 0.2 ms. By examining the graphs we see that there are no discontinuities, which would indicate timing problems. Testing also showed that there were no timing or concureency problems.

 

By using a handheld Korg guitar tuner. We saw that our tune frequencies where within 1% of the intended value. The resolution on this device is not very good, so that is the closest we could estimate the frequency. Our calculated accuracy is 0.5%.

 

There may be some RF interference from the long wire going to the CPU. We don’t think this is very significant because it didn’t disrupt our input signal. Therefore it’s unlikely we disrupted other groups’ devices.

 

The device is very user friendly. The user sees which string they are tuning on the LCD, can select a new string by pushing one of six buttons, and can see the deviation in frequency on the five LEDs of the STK500 board.