A VLSI architecture for a frequency-agile single-chip 10-MBaud digital QAM modulator

Cho, Kyung‐Ho; Putnam, J.; Samueli, H.

doi:10.1109/glocom.1999.831629

Cited by 4 publications

References 6 publications

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A frequency-agile single-chip QAM modulator with beamforming diversity

Cho¹,

Samueli

2001

IEEE J. Solid-State Circuits

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Architecture and circuit design techniques for VLSI implementation of a single-chip quadrature amplitude modulation (QAM) modulator with frequency agility and antenna beamforming characteristics are presented. In order to achieve reliable wireless communication modem function, the single chip all-digital QAM modulator implements various features, including high data rates with bandwidth efficiency, flexibility, meeting a wide variety of user throughput requirements with variable and width and data rates in a multiuser system, and robustness, incorporating diversity and redundancy techniques to guarantee robust communication for various operating environments. The modulator components consist of several digital processing building blocks, including various finite-impulse-response (FIR) filters, an innovative variable interpolation filter, a four-channel frequency translator with quadrature mixer for antenna beamforming diversity, a quadrature direct digital frequency synthesizer (QDDFS), a numerically controlled oscillator (NCO), a QAM formatter, a pseudorandom noise (PN) generator, an sin filter, and a microcontroller interface. An optimized architecture and chip implementation for the variable modulator is derived and evaluated which will support symbol rates from 6 kBaud to 8.75 MBaud continuously and digitally flexible IF frequencies up to 70 MHz with four-channel antenna beamforming function.

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A frequency-agile single-chip QAM modulator with beamforming diversity

Cho¹,

Samueli

2001

IEEE J. Solid-State Circuits

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A multicarrier QAM modulator

Vankka¹,

Kosunen²,

Sanchis³

et al. 2000

IEEE Trans. Circuits Syst. II

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A multicarrier quadrature amplitude modulation (QAM) modulator has been developed and implemented with programmable logic devices. The multicarrier QAM modulator contains four CORDIC-based QAM modulators. A conventional QAM modulator needs two multipliers, one adder, and sine/cosine ROM's. The designed CORDIC-based QAM modulator has about the same logic complexity as the two multipliers and the adder with the same word sizes. Each QAM modulator accepts 13-bit in-phase and quadrature data streams, interpolates them by 16, and upconverts the baseband signal to a selected center frequency. The frequencies of the four carriers can be independently adjusted. The proposed multicarrier QAM modulator does not use an analog modulator, and therefore, the difficulties of adjusting the dc offset, phasing, and the amplitude levels between the in-phase and quadrature-phase signal paths are avoided. The multicarrier QAM modulator is designed to fulfill the spectrum and error vector magnitude (EVM) specifications of the wideband code-division multiple-access (WCDMA) system. The simulated EVM is 1.06% root mean square (rms), well below the specified 12.5% rms for WCDMA. The measured ratio of the integrated first/second /third adjacent channel power (4.096-MHz bandwidth) to the integrated channel power (4.096-MHz bandwidth) is −68.16/−68.24/−66.17 dB versus the specified −45/−55/−55 dB.Index Terms-CORDIC algorithm, multicarrier, programmable logic devices, quadrature amplitude modulation, wideband codedivision multiple access..

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A 8.75-MBaud single-chip digital QAM modulator with frequency-agility and beamforming diversity

Cho¹,

Samueli²

Proceedings of the IEEE 2000 Custom Integrated Circuits Conference (Cat. No.00CH37044)

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A VLSI architecture for a frequency-agile single-chip 10-MBaud digital QAM modulator

Cited by 4 publications

References 6 publications

A frequency-agile single-chip QAM modulator with beamforming diversity

A frequency-agile single-chip QAM modulator with beamforming diversity

A multicarrier QAM modulator

A 8.75-MBaud single-chip digital QAM modulator with frequency-agility and beamforming diversity

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