Switched-capacitor digital-analogue converters with built-in FIR filtering

Summary form only given. The traditional solutions for the conversion of digital signals into the continuous-time domain include a digital-to-analog converter (DAC) followed by a reconstruction filter. Since ordinary DACs only provide a very low selectivity filtering action due to the particular sampling format of the output signal, the reconstruction filter alone is responsible for the shaping of the output imaging spectrum. The authors propose a type of DAC which incorporates an FIR (finite-impulse-response) transfer function, and which can, therefore, allow a considerable reduction of the selectivity requirements of the reconstruction filter, or even their elimination. These devices, realized using switched-capacitor techniques, are attractive for integrated circuit fabrication, and their good performance is demonstrated by means of a simple discrete component model.<>