Delta-Sigma Modulator Using a Resonant-Tunneling Diode Quantizer

Miwa MUTOH  Hiroyuki FUKUYAMA  Toshihiro ITOH  Takatomo ENOKI  Tsugumichi SHIBATA  

IEICE TRANSACTIONS on Electronics   Vol.E85-C   No.5   pp.1219-1221
Publication Date: 2002/05/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Electronic Circuits
RTD quantizer,  delta-sigma modulator,  three cascoded RTD quantizers,  quantization noise,  number of harmonics,  

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A novel delta-sigma modulator that utilizes a resonant-tunneling diode (RTD) quantizer is proposed and its operation is investigated by HSPICE simulations. In order to eliminate the signal-to-noise-and-distortion ratio (SINAD) degradation caused from the poor isolation of a single-stage quantizer (1SQ), a three-stage quantizer (3SQ), which consists of three cascoded RTD quantizers, is introduced. At a sample rate of 10 Gsps (samples per a second) and a signal bandwidth of 40 MHz (oversampling ratio of 128), the modulator demonstrates a SINAD of 56 dB, which corresponds to the effective number of bits of 9.3.