Concurrent dual-band 1-bit digital transmitter using band-pass delta-sigma modulator

This paper proposes a 1-bit digital transmitter able to output concurrent dual-band RF signals using band-pass delta-sigma modulator (BP-DSM). The transmitter consists of two BP-DSMs that share a portion of feedback loop to generate two stop-bands to suppress the quantization noise in the dual-band and meanwhile keep the stability after the combination of the BP-DSMs. The transmitter complexity is just proportional to each bandwidth of the dual-band RF signals and is irrelevant to the carrier spacing between the two bands. Measurement results demonstrate that two LTE signals with 5 MHz bandwidth at 0.8 GHz and 1.5GHz, respectively, are generated with the proposed transmitter using a single bit digital data stream of 3.9 Gbps, with high adjacent channel leakage ratio (ACLR) of 50dB at 0.8GHz and 48dB at 1.5GHz.