Inter-band carrier aggregation digital transmitter architecture with concurrent multi-band delta-sigma modulation using out-of-band noise cancellation

Concurrent multi-band delta-sigma modulation (CMB-DSM) with out-of-band noise cancellation is presented for the first time. A scaled replica modulator creates anti-phased quantization noise for multi-band noise cancellation, consequently reducing adjacent channel leakage and significantly relaxing the design of a multi-band RF filter to suppress undesirable out-of-band emission. A prototype digital transmitter is designed with 6th-order CMB-DSM using a loop filter with stability compensation. Experimental results show that the proposed noise cancellation technique achieves more than 15-dB suppression on the out-of-band quantization noise with LTE inter-band carrier aggregation (CA) on 856 MHz and 1450 MHz bands with 40-MHz aggregated channel bandwidth.