A low pass filter based integrator in a digital feedback loop AGC for WLAN receivers
Keywords:Automatic Gain Control, Quadrature Amplitude Multiplexing, Wireless Local Area Network, Feedback AGC.
This paper describes a Digital feedback loop automatic gain control (AGC) for Wireless Local Area Network (WLAN) receivers. The proposed AGC employs a novel lowpass filter-based integrator for the gain generation, which controls digital multiplier to maintain constant signal dynamic range. The AGC performance is analyzed for 16 and 64 Quadra-ture Amplitude Multiplexing-Orthogonal Frequency Division Multiplexing (QAM-OFDM) modulated signal with differ-ent attenuation factors under Additive White Gaussian Noise (AWGN) channel. The proposed AGC has a dynamic range of 70dB with the gain error less than ±1dB and settling time is 1.2µs. The proposed algorithm is validated on a Field Programmable Gate Array (FPGA) platform.
 Jiangfeng Wu, Giuseppe Cusmai, Acer Wei-Te Chou et al, (2016, April). A 2.7 mW/Channel 48â€“1000 MHz Direct Sampling Full-Band Cable Receiver, In IEEE Journal of solid-state circuits, Vol. 51, No. 4, (pp. 213-215).
 Shen Yuyao, Wang Yongqing, Sheng Dewey, Wu Siliang. (2015, February). Digital AGC Based on Coherent Adjustment Cycle for DSSS Receiver. In China Communications, Vol. 12, No. 2, (pp. 95-106). https://doi.org/10.1109/CC.2015.7084405.
 Okjune Jeon, Robert M. Fox, Brent A. Myers. (2006- October). Analog AGC Circuitry for a CMOS WLAN Receiver. In IEEE Journal of Solid-State Circuits, Vol. 41, No. 10, pp. 2291-2300, Oct. 2006. https://doi.org/10.1109/JSSC.2006.881548.
 Sagar Ray, Mona Mostafa Hella. (2016, February). A 10 GB/s Inductor less AGC Amplifier with 40 dB Linear Variable Gain Control in 0.13 Î¼m CMOS. In IEEE Journal of Solid-State Circuits, Vol. 51, No. 2, (pp. 440-456). https://doi.org/10.1109/JSSC.2015.2496782.
 Tingting Mo, Jianjun Zhou. (2012, November). Reconfigurable Dual-Channel Multiband RF Receiver for GPS/Galileo/BD-2 Systems. In IEEE Transactions on Microwave Theory and Techniques, Vol. 60, No. 11, (pp. 3491-3501). https://doi.org/10.1109/TMTT.2012.2216287.
 Thangarasu Bharatha Kumar, Kaixue Ma, Kiat Seng Yeo. (2012-November).7.9-mW 5.6-GHz Digitally Controlled Variable Gain Amplifier with Linearization, In IEEE Transactions on Microwave Theory and Techniques, Vol. 60, No. 11, (pp. 3482-3490). https://doi.org/10.1109/TMTT.2012.2217151.
 Wang Jingdian, LU Xiuhong, Zhang Li. (2018, December). Modeling of a Multiple Digital Automatic Gain Control System, In Tsinghua Science and Technology, Vol. 13, No. 6, (pp. 807-811). https://doi.org/10.1016/S1007-0214(08)72204-1.
 E. Tisserand and Y. Berviller. (2016, October). Design and Implementation of a New Digital Automatic Gain Control. In Electronics Letters, Vol. 52, No. 22, Apr. 2016 (pp. 1847-1849). https://doi.org/10.1049/el.2016.1398.
 Di Lin, Yin-Tang Yang, Zhan Jing, Zuo-Chen Shi, Yang Liu. (2014, January). A fully integrated feedback AGC loop for ZigBee (IEEE 802.15.4) RF transceiver applications. In Microelectronics Journal, Elsevier, Vol. 45, (pp. 657-665).
 Y.J. Zheng, J.N. Yan, Y.P. Xu. (2008, December). A CMOS VGA with DC offset cancellation for direct- conversion receiversâ€, In IEEE Trans. Circuits Systems, Vol. 56, No. 1, (pp. 103-113).
 Sunyoung Ki, Namjun C ho, Seong-Jun Song, and Hoi-Jun Yoo. (2007, October). A 0.9 V 96 _W Fully Operational Digital Hearing Aid Chip. In IEEE Journal of Solid-State Circuits, Vol. 42, No. 11, (pp. 2432-2440).
 Xiaoman Wang, Baoyong Chi, Zhihua Wang. (2010, January). A Low-Power High-Data-Rate ASK IF Receiver with a Digital-Control AGC Loop. In IEEE Transactions on Circuits and Systems, Vol. 57, No. 8, (pp. 617-621).
 Hsin Wang, Shen-Iuan Liu. (2008, March). 0.18-Âµm CMOS 1.25-Gbps Automatic-Gain-Control Amplifier. In IEEE Transactions on Circuits and Systems-II: Express Briefs, Vol. 55, No. 2, (pp. 136-140).
 Di Li, Yin Tang Yang, Zhan Jing, Zuo Chen Shi, Yang Liu. (2014, May). A fully integrated feedback AGC loop for ZigBee (IEEE 802.15.4) RF transceiver applications. In Microelectronics Journal, Elsevier, Vol. 45, (pp. 657-665).
 E. Tisserand and Y. Berviller. (2016, Oct). Design and implementation of a new digital automatic gain control. Electronics Letters, Vol. 52, No. 22, (pp. 1847â€“1849). https://doi.org/10.1049/el.2016.1398.