Title :
A Delta-Sigma Pulse-Width Digitization Technique for Super-Regenerative Receivers
Author :
Liu, Yao-Hong ; Lin, Tsung-Hsien
Author_Institution :
Dept. of Electr. Eng., Nat. Taiwan Univ., Taipei, Taiwan
Abstract :
This paper presents a delta-sigma pulse-width digitizer (ΔΣ-PWD) architecture designed for a super-regenerative receiver (SR-RX) operated at the 400-MHz Medical Implantable Communications Service (MICS) band. The ΔΣ-PWD employs the operation principle of a ΔΣ modulator to convert the pulse-width (PW) value into digital domain and achieve fine resolution, which allows the SR-RX to support the 2-ASK/4-ASK modulations. It can be considered as the PW domain counterpart of a conventional ΔΣ modulator. The proposed architecture is capable of suppressing the PW quantization error over the direct-sampling-type PW detector by 23 dB. A linear model for the ΔΣ-PWD is devised in this paper for system analysis and design optimization. Fabricated in a 0.18-μm CMOS process, the whole receiver draws 700 μA from a 1.3-V supply, while the ΔΣ-PWD consumes only 100 μA. When operated on the 4-ASK modulation signal with 312-kbps data rate, the receiver achieves an energy efficiency of 2.9 nj/bit and -76-dBm sensitivity.
Keywords :
CMOS integrated circuits; amplitude shift keying; biomedical communication; delta-sigma modulation; optimisation; receivers; ΔΣ modulator; 2-ASK modulations; 4-ASK modulations; CMOS process; PW quantization error; bit rate 312 kbit/s; current 100 muA; current 700 muA; delta-sigma pulse-width digitization technique; design optimization; energy 2.9 nJ; frequency 400 MHz; gain 23 dB; loss 76 dB; medical implantable communications service band; super-regenerative receiver; system analysis; voltage 1.3 V; Amplitude shift keying; Detectors; Oscillators; Quantization; Receivers; Sensitivity; Amplitude-shift keying (ASK); delta-sigma modulator; pulse-width detection; super-regenerative receiver;
Journal_Title :
Solid-State Circuits, IEEE Journal of
DOI :
10.1109/JSSC.2010.2061614
