Nt1310 Unit 4

The first part of the experiment was determining the resolution of the DAC in volts. Before a voltage was applied the noise was determined by measuring the DC offset, the reading of the DMM at an input of zero volts. This offset was removed from the recorded values in order to provide a more accurate reading of the resolution. These corrected values and their corresponding applied voltages can be found in Table 1 of the appendix. The lowest value recorded from the DMM was -9.968V and the highest value recorded was +9.968V making the range of the DMM about 19.94±0.01V. Using the equation for calculating resolution, the resolution was calculated for values of N from 10 to 18 in increments of 2 (recorded in Table 2). Considering that the DAS is a 16-bit system, the highest resolution the DAC could achieve is 3.052E-4V or 305μV. This was confirmed by comparing the calculated values for resolution against the values the DMM displayed. At 18-bits or higher the voltage readings are about the same as DC offset because the values have become so small it is difficult for the DMM to …show more content…
However, depending on the resolution needed for a measurement, N (number of bits) can be reduced to make the measurement more efficient. For instance, a 12-bit system can be used if a resolution around 10mV is needed, but it might be better to use a lower bit system instead. Although for the DAS in this experiment, the data in Table 3 shows that the resolution did not jump exactly 305μV every step, any discrepancies can be attributed to random errors due to the instruments that were used. Despite this error, Figure 1 still shows how the resolution changed by about 300μV each time which proves that the resolution of the system has been calculated correctly. Checking the step size of the resolution was only important to ensure that the resolution for the system had been determined