A 2-GHz carrier leakage calibrated direct-conversion WCDMA transmitter in 0.13-/spl mu/m CMOS

Brenna, G.; Tschopp, David; Rogin, Jurgen; Kouchev, I.; Huang, Qiuting

doi:10.1109/jssc.2004.831794

Cited by 68 publications

(22 citation statements)

References 4 publications

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“…To consider the carrier leakage, especially in low gain mode, the leakage signals are difficult to scale down with decreased output signal as the gain varies at baseband [16,17]. The gain control range is hence all implemented at RF band because the carrier leakage in the I/Q modulator output can be attenuated through the RF VGA.…”

Section: Architecturementioning

confidence: 99%

A calibrated direct conversion front-end transmitter with resonant matching techniques for mobile WiMAX/WiBro applications

Chang

Jou

2011

Analog Integr Circ Sig Process

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A direct conversion front-end transmitter with the properties of high linearity and high single sideband rejection ratio is described in this paper. The transmitter employs two resonant matching techniques to improve its operating bandwidth. The first resonant circuit design is applied at the inter-stage of the LO input buffer in order to achieve a wideband frequency response which ranges from dc to 6 GHz. The second resonant circuit is applied at the power amplifier (PA) driver output stage to increase the matching bandwidth and meet both the Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Broadband (WiBro) applications simultaneously. In addition, the sideband signal and carrier leakage of this transmitter are further minimized by a proposed calibration circuit design to achieve the error vector magnitude (EVM) specifications. The measured single sideband performance with calibration mechanism demonstrates approximately 15 dB improvement on sideband and carrier suppression. The rejected sideband and carrier signals can be up to 55.19 and 56.31 dBc, respectively. The measured dynamic gain range of the transmitter is 53 dB in 1-dB step with a maximum relative gain error lower than 0.4 dB. The transmitter delivers ?0.766 dBm output power with EVM of -34.687 dB for the orthogonal frequency division multiple access (OFDMA) 64QAM-3/4 modulated signals. The measured constellation is minimized to be\1.5% with output power from -2.3 to -36.2 dBm.

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Section: Architecturementioning

confidence: 99%

A calibrated direct conversion front-end transmitter with resonant matching techniques for mobile WiMAX/WiBro applications

Chang

Jou

2011

Analog Integr Circ Sig Process

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“…The I/Q modulator is a key device of zero-IF transmitter [7] . The EVM of transmitter has a great relationship with the carrier leakage and the image product caused by the I/Q modulator.…”

Section: I/q Modulatormentioning

confidence: 99%

A low EVM zero-IF RF transmitter for cognitive radio application

Zhang

Zhu

Liu

et al. 2010

J. Electron.(China)

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A zero-IF transmitter for Cognitive Radio (CR) application is presented. To effectively reduce the interference between Power Amplifier (PA) and Voltage Controlled Oscillator (VCO), two VCOs are adopted, one is 450 MHz and the other is from 1148 MHz to 1252 MHz with an 8 MHz step, so the frequency of them are different from the operational frequency of PA. The Local Oscillator (LO) of the modulator generated by mixing the signals of the two VCOs has a low phase noise of -82 dBc/Hz with an offset of 1 kHz. The measurement result of the transmitter shows that the Adjacent Channel Power Ratio (ACPR) is less than -47.5 dBc at 27 dBm output, and the Error Vector Magnitude (EVM) is less than 1.7%.

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“…Again, due to the modest Q value of on-chip inductors, typically use of a costly SAW filter before the power amplifier is inevitable [14][15][16]. On the other hand, as a result of the aggressive advancement toward more integration, this external SAW filter has been removed in some designs [14,[17][18][19]. However, without deploying a proper on-chip filtering mechanism and due to the stringent noise requirements, this would result in excessive transmitter power dissipation.…”

Section: Introductionmentioning

confidence: 99%