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Quadrature delta sigma modular design with adjustable bandwidth and center frequency
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Alireza Shamsi *   |
| Department of Electrical Engineering, Shahid Sattari Aeronautical University of Science and Technology, Tehran, , alireza.shamsi@ssau.ac.ir |
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Abstract: (9072 Views) |
In this paper, a flexible Continuous time (CT) feedforward (FF) quadrature delta sigma modulator (QDSM) with variable bandwidth (BW) is proposed. The modulator BW and center frequency (fc) are variable which can be adjusted with two separate parameters. The modulator signal-to-noise ratio (SNR) will be optimized by these parameters at every center frequency and bandwidth. The modulator BW is changed by varies in the complex coefficients, and the structure of the modulator is no changed.
The proposed modulator is usable in multi standard receivers as well as in receivers with variable frequency input signal or frequency hopping. The center frequency of this modulator is from 0 to 1/4 fs and its bandwidth can be changed from zero to 1/12 fs.An example of quadrature modulator is designed with the proposed design method at the circuit level. The modulator is simulated for 2MHz and 5MHz bandwidths with a sampling frequency of 64MHz. The SNR for these bandwidths are 76.42dB and 56.59dB, respectively. The FOM has been calculated to be 0.375 and 1.46 (pj / conv), respectively.
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| Keywords: quadrature delta sigma modulator, Continuous Time, Programmable Bandwidth, Analog to Digital Converter (ADC) |
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Full-Text [PDF 1634 kb]
(989 Downloads)
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Type of Study: Research |
Subject:
ADC
Received: 2018/12/31 | Accepted: 2019/05/25 | Published: 2020/01/22
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