Digital OFDM transmitter based on multi-bit delta sigma modulator

An orthogonal frequency division multiplexing transmitter based on multi-bit delta sigma modulator with switch mode power amplifiers is presented. Multi-bit up-conversion mixer and power amplifiers are revealed. With a 3-bit delta sigma modulator, an IEEE 802.11a based transmitter is simulated. Results show that the error vector magnitude of this transmitter achieves -20.74dB for 64-QAM. With up to +10% gain imbalance for the most significant bit, the transmitter's accuracy degrades 1.5dB.