METHOD FOR INTERPOLATING INTERMEDIATE VALUES IN A CLOSED LOOP SYSTEM
Original Publication Date: 1992-Dec-01
Included in the Prior Art Database: 2002-Jan-22
As a specific example (Figure 2), it may be required to display the power output of an amplifier to the nearest watt, but the A/D used to detect the power level can only resolve 4-watt steps. In the example shown, the power output is dependent on the gain of the amplifier. The gain of the ampliier is adjustable. To adjust the gain, the microprocessor outputs an S-bit word to the S-bit D/A converter. The analog level output from the D/A is used to control the gain of the ampliier. As the gain is changed, the output from the amplifier is also changed. The output level is detected by the level detector and sent to the internal 6-bit A/D. The microprocessor drives a digital level meter that displays the output level. Note that because the D/A has higher resolution, several steps of D/A level adjustment may t&e place before any AID input change is noted. It is this added control capability that allows the intermediate values to be interpolated.