An analog modulator/demodulator using a programmable arbitrary waveform generator

We present an analog implementation of a modulator/demodulator (programmable analog modulator/demodulator, PAMD) for analog signal processing applications. The PAMD architecture is fully programmable enabling it to be used for a variety of communication schemes and not specifically for a particular application. PAMD uses an architecture similar to a direct digital frequency synthesis implementation to generate the waveforms. We use our programmable floating-gate MOS transistors as analog memory cells to store easily programmed samples of the waveforms. Experimental results showing the programmability along with both modulation and demodulation using the presented architecture are presented. The IC prototype generating eight programmable waveforms was fabricated in a 0.5 μm n-well CMOS process and occupies 0.95 mm² of area.