2 Perform Measurements

It is critical to the reliability of this test that the load resistance be a known calibrated value. It is best to measure this using a 4-wire connection for the most accurate value. Several calculations will depend on the accuracy of this value.

The test will proceed in a stepwise manner across output power. At each power level of concern, the following data should be recorded:

Measuring both Voltages and Digital inputs require changing the AP Input source between the HiRes A/D Converter and the Digital inputs.

Figure 2-1 Measuring Analog Voltages - Use HiRes A/D

Figure 2-2 Measuring Digital Outputs - Use Digital Interface

Proceed to capture each of the above values, step the output power to the next amplitude, and repeat until the full output range under test is captured. However, in this configuration, the pilot tone amplitude is a scalar ratio of the fundamental. You only want to increase the magnitude of the fundamental, so this ratio will require adjustment at each step. Setting the ratio and the amplitude in units of dB will allow for easy adjustments. As long as the sum of the ratio and amplitude is kept constant, the pilot tone amplitude should remain fixed.

Once data collection is complete, you can perform calculations for each output level to determine accuracy.

It is necessary to determine the full scale voltage and current values from the data sheet of the amplifier being used. For example, you can pull this information for TAS2562 in Figure 2-3:

Figure 2-3 TAS2562 Full Scale Values