2003 Fiscal Year Final Research Report Summary
Ultrahigh-speed bandpass delta-sigma modulators using resonant-tunneling devices
| Project/Area Number |
14550330
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
電子デバイス・機器工学
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| Research Institution | Sophia University |
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Principal Investigator |
WAHO Takao Sophia University, Dept.Electrical and Electronics Eng., Professor, 理工学部, 教授 (90317511)
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| Project Period (FY) |
2002 – 2003
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| Keywords | resonant-tunneling / delta-sigma modulator / bandpass / HEMT / continuous-time / multi-bit / international / Germany |
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| Research Abstract |
By using resonant-tunneling diodes (RTDs) and high-electron-mobility transistors (HEMTs), multi-GHz continuous-time multi-bit delta-sigma modulators have been designed. Fundamental circuit blocks, such as quantizers and Gm-C filters, were designed first. The present 2-bit quantizer consisted of four conventional single-ended ones to obtain a quasi-differential operation mode. The filters employed fully differential HEMT operational amplifiers. The lowpass and bandpass delta-sigma modulators were then constructed by combining these circuit blocks. Transistor-level circuit simulation was carried out by assuming InP-based RTD/HEMT technology. A lowpass modulator was successfully designed with a 9-bit resolution and a100-MHz input bandwidth BW at a clock frequency f_c of 13 GHz. Regarding a bandpass modulator, a 7-bit resolution was obtained for BW=30 MHz and f_c=4 GHz. Since the design method have been clarified including an RTD device model used in the circuit simulation, further improvement in performance is possible by optimizing circuit parameters in the future. Our study clearly demonstrated a high potential of RTD/HEMT-based multi-GHz delta-sigma modulators.
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