Digital Electronics: Principles, Devices and Applications

492 Digital Electronicssmallest when D has the full-scale value. Figure 12.22 shows the noninverting type of programmableintegrator. The output in this case is given by∫V o = D/CR 1 V in dt (12.10)12.7.4 Low-Frequency Function GeneratorFigure 12.23 shows one possible circuit configuration of a D/A converter based low-frequency functiongenerator. There is no limit to the lowest frequency possible using this configuration. The upper limitCR FBOUT-1−−V refV inFigure 12.22 Non-inverting programmable integrator.OUT-2+R 1+V inV refR FBOUT-1D/AConverterOUT-2−+−+V oSignROMClockCounterFigure 12.23Low-frequency function generator.