鑒於無線通訊系統對於高資料傳輸率與高能源效率的需求日益增加，傳統直接轉頻發射機設計正面臨諸多實行面上的嚴峻挑戰。盱衡目前文獻，功率放大器非線性失真以及本地振盪源牽引效應乃是惡化射頻訊號完整性的關鍵因素。在本論文研究中，上述兩項議題皆被嚴謹地分析，藉此了解其對直接轉頻發射機輸出訊號品質的惡化並研擬改善方法。基於以上思維，本論文共涵蓋兩項研究主題。首先，針對本地振盪源受到調制訊號自我注入干擾現象建立完整的理論模型，以此分析牽引效應對發射機訊號品質的影響。基於理論推導，本論文提出一項利用最佳化鎖相迴路參數並且使用一內部自我注入迴路的整合方法來改善本地振盪源之牽引效應。其次，於時變波包調制系統中，本論文探討功率放大器非線性失真與本地振盪源牽引現象兩者複合效應對於直接轉頻發射機所造成的負面影響。欲全面性提升發射機線性度，本論文提出一項結合開回路數位預失真技術與類比回授補償機制之發射機架構，能有效地改善功率放大器線性度與抵抗發射機本地振盪源牽引效應。在實驗上則將上述方法實施在一發射機原型用以輸出cdma2000 1x與WCDMA QPSK調制訊號做為驗證。本論文經由嚴謹的理論分析與實驗確認所提出之發射機訊號品質改善方法，於未來複雜與寬頻調制無線通訊系統中，具備很好的應用潛力。

In the wireless communication system, owing to the increasing demands for high data rates and high energy efficiency, several practical implementation-related challenges arise in the design of conventional direct-conversion transmitter (DCT). According to the existing literatures, power amplifier (PA) nonlinear distortions and local oscillator (LO) pulling effects are the most critical factors to deteriorate the RF signal integrity. In this doctoral research, the above two issues have been rigorously investigated, and hence improved, the resultant degradation of DCT output signal quality. Based on the above thought, this dissertation includes two topics. The first topic begins with a theoretical analysis of a LO under directly modulated self-injection, which accounts for the transmitted signal quality deterioration due to pulling effects. Based on the presented theoretical deduction, an integrated approach by incorporating PLL parameters optimization and inner self-injection loop is proposed to mitigate the pulling effect. Furthermore, the next topic of this dissertation is dedicated to elucidate how the combined effects of PA distortion and LO pulling adversely impact a DCT in time-varying envelope modulation systems. To comprehensively enhance the transmitter linearity, an improvement approach for PA linearization and anti-LO pulling is developed by combining an open-loop digital predistortion (DPD) method and the proposed analog feedback compensation mechanism. Experiments are conducted to verify the feasibility of the proposed improvement approaches by implementing a prototype transmitter delivering the cdma2000 1x and WCDMA QPSK-modulated signals. Rigorous theoretical analysis and experimental verification prove that the proposed approaches to improving the DCT signal quality has great potential for application in the future complex modulation and wide bandwidth wireless communication systems.

Contents


1 Introduction 1
1.1 Research Motivation 1
1.2 Local Oscillator Pulling 2
1.2.1 Injection Pulling on Phase-Locked Oscillator 2
1.2.2 Mitigation Approach 3
1.3 Power Amplifier Nonlinearity and Linearization 4
1.3.1 AM-AM and AM-PM Distortion 5
1.3.2 Linearization Techniques 6
1.4 Dissertation Objectives and Organization 8
2 Analysis of Local Oscillator Pulling Effects on Direct-Conversion Transmitter in Constant Envelope Modulation Systems 9
2.1 Introduction 9
2.2 Local Oscillator Pulling Effects Model 11
2.2.1 Generalized Locking Equation 11
2.2.2 Self-Injection Pulling Effects on Phase-Locked Loops 14
2.2.3 PLL Parameter Impact 18
2.3 Improvement Approach and Results Discussion 21
2.3.1 Inner Self-Injection Loop 23
2.3.2 Applicable Parameters 26
2.3.3 Optimal Design Strategy 29
2.3.4 Spectral Regrowth Improvement 30
2.4 Summary 32
3 Direct Conversion Transmitters with Resistance to Combined Effects of Power Amplifier Distortion and Local Oscillator Pulling 33
3.1 Introduction 33
3.2 Analysis of the Combined Effects of PA Distortion and LO Pulling 35
3.2.1 Power Amplifier Distortion 35
3.2.2 Local Pulling Effect 37
3.3 Proposed Improvement Approach 41
3.3.1 Baseband Digital Predistortion 43
3.3.2 Second-Point VCO Modulation 45
3.3.3 Inner Self-Injection Loop 48
3.4 Improvement Results Discussion 50
3.4.1 Ability to Improve LO Pulling Effects in Time-Varying Envelope Modulation System 50
3.4.2 Ability to Resist PA Nonlinear Distortions and LO Pulling Effects 53
3.4.3 Ability to Enhance DCT Linearity and Average Efficiency 55
3.5 Summary 59
4 Conclusions 60
Bibliography 62
Vita 68


















List of Figures


1.1 Illustration of transmitted signal quality degradation owing to combined effects of PA distortion and LO pulling in a DCT 2
1.2 Digital polar transmitter incorporating a digitally controlled delay (DCD) for mitigation of digitally controlled oscillator (DCO) frequency pulling by the digital power amplifier (DPA) 3
1.3 Illustration of power amplifier AM-AM and AM-PM conversion characteristic 5
1.4 Illustration the application of correction linearizing to a PA 6
1.5 Block diagram of the predistortion system 7
1.6 Block diagram of a transmitter with baseband digital predistorter 8

2.1 Block diagram of an oscillator under injection 11
2.2 Vector diagram of the signals in the oscillator under injection 12
2.3 Time-domain phase dynamics of a PLL under injection 14
2.4 Frequency-domain model for analyzing phase noise and modulation accuracy of a directly modulated self-injection PLL 15
2.5 Block diagram of the LO pulling test setup for a direct-conversion GMSK transmitter 19
2.6 Analysis of LO pulling effects and validation under various PLL phase margins. (a) Calculated magnitude of the reference and oscillator noise transfer functions. (b) Calculated magnitude of the PM injection noise transfer functions. (c) Calculated LO phase noise. (d) Measured LO phase noise (e) Calculated and measured transmitter EVMs. 20
2.7 Analysis of LO pulling effects and validation under various PLL bandwidths. (a) Calculated magnitude of the reference and oscillator noise transfer functions. (b) Calculated magnitude of the PM injection noise transfer functions. (c) Calculated LO phase noise. (d) Measured LO phase noise (e) Calculated and measured transmitter EVMs 22
2.8 Block diagram of the pulling test setup for the direct-conversion GMSK transmitter with an inner self-injection loop 23
2.9 Photo of the experimental setup. 23
2.10 Frequency-domain model for analyzing phase noise and modulation accuracy of a dual self-injection PLL 24
2.11 Improvement of LO pulling effects and validation under various inner self-injection power ratios. (a) Calculated magnitude of the reference and oscillator noise transfer functions. (b) Calculated magnitude of the PM injection noise transfer functions. (c) Calculated LO phase noise. (d) Measured LO phase noise (e) Calculated and measured transmitter EVMs 25
2.12 Improvement of LO pulling effects and validation under various inner self-injection angles. (a) Calculated magnitude of the reference and oscillator noise transfer functions. (b) Calculated magnitude of the PM injection noise transfer functions. (c) Calculated LO phase noise. (d) Measured LO phase noise (e) Calculated and measured transmitter EVMs 27
2.13 Improvement of LO pulling effects and validation under various inner self-injection delays. (a) Calculated magnitude of the reference and oscillator noise transfer functions. (b) Calculated magnitude of the PM injection noise transfer functions. (c) Calculated LO phase noise. (d) Measured LO phase noise (e) Calculated and measured transmitter EVMs 29
2.14 Comparison of EVM performance by selecting different combinations of the PLL and inner self-injection parameters 30
2.15 Measured DCT output spectra for comparing the LO pulling effects between with and without improvement 31

3.1 System analysis model of a DCT with combined effects of PA distortion and LO pulling 37
3.2 Comparison of output signal quality under different distortion mechanisms when DCT delivers a 1.98 GHz QPSK-modulated signal with a 1.25 MHz channel bandwidth. (a) Transmit spectrum (b) Constellation 40
3.3 Block diagram of the proposed transmitter experimental setup for improving the combined effects of PA distortion and LO pulling 42
3.4 System analysis model of the experimental DCT shown in Figure 3.3 42
3.5 Photo of the experimental setup 43
3.6 Block diagram of the baseband digital predistorter. 44
3.7 Illustration of the proposed second-point VCO modulation approach (a) Block diagram of the experiment setup (b)System analysis model 46
3.8 Illustration of the proposed inner self-injection approach (a) Block diagram of the experiment setup (b)System analysis model 49
3.9 Comparison of transmitter EVMs among different improvement options 51
3.10 Comparison of transmitter output spectra among different improvement options. (a) Measured results. (b) Simulated results 51
3.11 Experimental results for the experimental DCT when delivering a 1.98 GHz cdma2000 1x QPSK-modulated signal with a channel bandwidth of 1.25 MHz and an OBO of 6 dB. (a) EVMs (b) ACPRs 53
3.12 Experimental results for the proposed DCT when delivering a 1.98 GHz WCDMA QPSK-modulated signal with a channel bandwidth of 3.84 MHz and an OBO of 8 dB. (a) EVMs (b) ACLRs 54
3.13 Experimental results for the proposed DCT when delivering a 1.98 GHz cdma2000 1x QPSK-modulated signal with a channel bandwidth of 1.25 MHz and a pulling signal power ratio of -65 dB. (a) EVM (b) ACPR 55
3.14 Experimental results for the proposed DCT when delivering a 1.98 GHz WCDMA QPSK-modulated signal with a channel bandwidth of 3.84 MHz and a pulling signal power ratio of -65 dB. (a) EVMs (b) ACLRs 56
3.15 Comparison of measured average efficiencies with respect to OBO for the proposed DCTs operating with a pulling signal power ratio of -65 dB. (a) Delivering a 1.98 GHz cdma2000 1x QPSK-modulated signal with a channel bandwidth of 1.25 MHz (b) Delivering a 1.98 GHz WCDMA QPSK-modulated signal with a channel bandwidth of 3.84 MHz 57
3.16 Experimental results of transmit spectra for the proposed DCTs operating with an OBO of 2.5 dB and a pulling signal power ratio of -65 dB. (a) 1.98 GHz cdma2000 1x QPSK-modulated signal with a channel bandwidth of 1.25 MHz. (b) 1.98 GHz WCDMA QPSK-modulated signal with a channel bandwidth of 3.84 MHz 58






List of Tables


1.1 Summary of PA input correction linearization techniques. 6

2.1 Comparison of ACPR results with and without improved as the DCT implemented in the GMSK modulation system 31

3.1 Comparison of ACPR results with and without improved as the DCT implemented in the cdma2000 1x modulation system 52

Bibliography



[1] B. Razavi, “Challenges in portable RF transceiver design,” IEEE Circuits and Devices Mag., vol. 12, no. 5, pp. 12–25, Sep. 1996.
[2] B. Razavi, “RF transmitter architectures and circuits,” in Proc. Custom Integrated Circuits Conf., San Diego, CA, 1999, pp. 197–204.
[3] S. C. Cripps, RF Power Amplifiers for Wireless Communications, Norwood, MA: Artech House, 1999.
[4] F. H. Raab, P. Asbeck, S. Cripps, P.-B. Kenington, Z.-B. Popovic, N. Pothecary, J. F. Sevic, and N.-O. Sokal, “Power amplifiers and transmitters for RF and microwave,” IEEE Trans. Microw. Theory Tech., vol. 50, no. 3, pp. 814–826, Mar. 2002.
[5] O.-E. Eliezer, R.-B. Staszewski, I. Bashir, S. Bhatara, and P.-T. Balsara, “A Phase Domain Approach for Mitigation of Self-Interference in Wireless Transceivers,” IEEE J. Solid-State Circuits, vol. 44, no. 5, pp. 1436–1453, May 2009.
[6] L. Anttila, P. Handel, and M. Valkama, “Joint Mitigation of Power Amplifier and I/Q Modulator Impairments in Broadband Direct-Conversion Transmitters,” IEEE Trans. Microw. Theory Tech., vol. 58, no. 4, pp. 730–739, April 2010.
[7] B. Van der pol, “Forced oscillations in a circuit with nonlinear resistance,” Phil. Msg., vol. 3, pp. 65–80, Jan. 1927.
[8] R. Adler, “A study of locking phenomena in oscillators,” Proc. IRE, vol. 34, no. 6, pp. 351–357, June 1946.
[9] L. J. Paciorek, “Injection locking of oscillators,” Proc. IEEE, vol. 53, no. 11, pp. 1723–1727, Nov. 1965.
[10] R. D. Huntoon and A. Weiss, “Synchronization of oscillators,” Proc. IRE, vol. 35, no. 12, pp. 1415–1423, Dec. 1947.
[11] K. Kurokawa, “Injection locking of microwave solid-state oscillators,” Proc. IEEE, vol. 61, no. 10, pp. 1386–1410, Oct. 1973.
[12] B. Razavi, “A study of injection locking and pulling in oscillators,” IEEE J. Solid-State Circuits, vol. 39, no. 9, pp. 1415–1424, Sep. 2004.
[13] C.-J. Li, C.-H. Hsiao, F.-K. Wang, T.-S. Horng, and K.-C. Peng, “A rigorous analysis of local oscillators pulling in frequency and discrete-time domain,” in 2009 IEEE Radio Frequency and Integrated Circuits Symp. Dig., pp. 409–412.
[14] J. Dominguez, A. Suarez, and S. Sancho, “Semi-analytical formulation for the analysis and reduction of injection-pulling in front-end oscillators,” in IEEE MTT-S Int. Microw. Symp. Dig., June 2009, pp. 1589–1592.
[15] R.-B. Staszewski, D. Leipold, and P.-T. Balsara, “Direct frequency modulation of an ADPLL for Bluetooth/GSM with injection pulling elimination,” IEEE Trans. Circuits Syst. II, Exp. Briefs, vol. 52, no. 6, pp. 339–343, June 2005.
[16] S. Mendel, C. Vogel, and N. Da Dalt, “A phase-domain all digital phase-locked architecture without reference clock retiming,” IEEE Trans. Circuits Syst. II, Exp. Briefs, vol. 56, no. 11, pp. 860–864, Nov. 2009.
[17] I. Bashir, R.B. Staszewski, O. Eliezer, K. Waheed, V. Zoicas, N. Tal, J. Mehta, M.-C. Lee, P.T. Balsara, and B. Banerjee, “An EDGE transmitter with mitigation of oscillator pulling,” in 2010 IEEE Radio Frequency Integrated Circuit Symp. Dig., pp. 13-16, May 2010.
[18] I. Bashir, R.-B. Staszewski, O.-E. Eliezer, and P.-T. Balsara, “A novel approach for mitigation of RF oscillator pulling in a polar transmitter,” IEEE J. Solid-State Circuits, vol. 46, no. 2, pp. 403–415, Feb. 2011.
[19] P. Lavrador, T.-R. Cunha, P. Cabral, and J.-C. Pedro, “The linearity-efficiency compromise,” IEEE Microw. Mag., vol. 11, no. 5, pp. 44–58, Aug. 2010.
[20] G.-T. Zhou and J.-S. Kenney, “Predicting spectral regrowth of nonlinear power amplifiers,” IEEE Trans. Commun., vol. 50, no. 5, pp. 718–722, May 2002.
[21] L.-C. Nunes, P.-M. Cabral, and J.-C. Pedro, “A physical model of power amplifiers AM/AM and AM/PM distortions and their internal relationship,” in IEEE MTT-S Int. Microwave Symp. Dig., vol., no., pp.1,4, June 2013.
[22] P. B. Kenington, High-Linearity RF Amplifier Design, Norwood, MA: Artech House, 2000.
[23] Y. Xin and J. Hong, “Digital predistortion using adaptive basis functions,” IEEE Trans. Circuits Syst. I, Reg. Papers, vol. 60, no. 12, pp. 3317–3327, Dec. 2013.
[24] J. K. Cavers, “Amplifier linearization using a digital predistorter with fast adaptation and low memory requirements,” IEEE Trans. Veh. Technol., vol. 39, no.4, pp. 374–382, Nov. 1990.
[25] K.-J. Muhonen, M. Kavehrad, and R. Krishnamoorthy, “Look-up table techniques for adaptive digital predistortion: a development and comparison,” IEEE Trans. Veh. Technol., vol. 49, no. 5, pp.1995–2002, Sept. 2000.
[26] W.-J. Kim, S.P. Stapleton, J.-H. Kim, and C. Edelman, “Digital predistortion linearizes wireless power amplifiers,” IEEE Microw. Mag., vol. 6, no. 3, pp. 54–61, Sept. 2005.
[27] H. H. Chen, C. H. Lin, P. C. Huang, and J. T. Chen, “Joint polynomial and look-up-table predistortion power amplifier linearization,” IEEE Trans. Circuits and Systems II, Exp. Briefs, vol. 53, no. 8, pp. 612–616, Aug. 2006.
[28] R. C. Mackey, “Injection locking of klystron oscillators,” IRE Trans. Microw. Theory Tech., vol. MTT-10, no. 4, pp. 228–235, Jul. 1962.
[29] H. L. Stover and R. C. Shaw, “Injection-locked oscillators as amplifiers for angle-modulated signals,” in 1966 IEEE G-MTT Int. Symp. Dig., pp. 60–66.
[30] H. R. Rategh and T. H. Lee, “Superharmonic injection-locked frequency dividers,” IEEE J. Solid-State Circuits, vol. 34, no. 6, pp. 813–821, June 1999.
[31] J.-S. Paek and S. Hong, “A 29 dBm 70.7% PAE injection-locked CMOS power amplifier for PWM digitized polar transmitter,” IEEE Microw. Wireless Compon. Lett., vol. 20, no. 11, pp. 637–639, Nov. 2010.
[32] C.-T. Chen, C.-H. Hsiao, T.-S. Horng, K.-C. Peng, and C.-J. Li, “Cognitive polar receiver using two injection-locked oscillator stages,” IEEE Trans. Microw. Theory Tech., vol. 59, no. 12, pp. 3484–3493, Dec. 2011.
[33] K. Kurokawa, “Noise in synchronized oscillators,” IEEE Trans. Microw. Theory and Tech., vol. MTT-16, no. 4, pp. 234–240, Apr. 1968.
[34] A. Mirzaei, M. E. Heidari, and A. A. Abidi, “Analysis of oscillators locked by large injection signals: generalized Adler’s equation and geometrical interpretation,” in Proc. IEEE Custom Integrated Circuits Conf., San Jose, CA, 2006, pp. 737–740.
[35] I. Ali, A. Banerjee, A. Mukherjee, and B.-N. Biswas, “Study of injection locking with amplitude perturbation and its effect on pulling of oscillator,” IEEE Trans. Circuits Syst. I, Reg. Papers, vol. 59, no. 1, pp. 137–147, Jan. 2012.
[36] X. Lai and J. Roychowdhury, “Capturing oscillator injection locking via nonlinear phase-domain macromodels,” IEEE Trans. Microwave Theory and Tech., vol. 52, no. 9, pp. 2251–2261, Sep. 2004.
[37] S. Srivastava, X. Lai, and J. Roychowdhury, “Nonlinear phase macromodel based simulation/design of PLLs with superharmonically locked dividers,” in Proc. IEEE Custom Integrated Circuits Conf., San Jose, CA, 2006, pp. 350–352.
[38] P. Maffezzoni and D. D’Amore, “Evaluating pulling effects in oscillators due to small-signal injection,” IEEE Trans. Computer-Aided Design of Integrated Circuits and Systems, vol. 28, no. 1, pp. 22–31, Jan. 2009.
[39] C.-J. Li, C.-H. Hsiao, F.-K. Wang, T.-S. Horng, and K.-C. Peng, “A rigorous analysis of a phased-locked oscillator under injection,” IEEE Trans. Microw. Theory and Tech., vol 58, no. 5, pp. 1391–1400, May 2010.
[40] C.-H. Hsiao, C.-J. Li, F.-K. Wang, T.-S. Horng, and K.-C. Peng, “Study of direct-conversion transmitter pulling effects in constant envelope modulation systems,” in IEEE MTT-S Int. Microw. Symp. Dig., May 2010, pp. 1174–1177.
[41] C.-H. Hsiao, C.-J. Li, F.-K. Wang, T.-S. Horng, and K.-C. Peng, “Analysis and improvement of direct-conversion transmitter pulling effects in constant envelope modulation systems,” IEEE Trans. Microw. Theory Tech., vol. 58, no. 12, pp. 4137–4146, Dec. 2010.
[42] H.-C. Chang, A. Borgioli, P. Yeh, and R.-A. York, “Analysis of oscillators with external feedback loop for improved locking range and noise reduction,” IEEE Trans. Microw. Theory and Tech., vol. 47, no. 8, pp. 1535–1543, Aug. 1999.
[43] L. Pan, Y. Bar-Ness, and J. Zhu, “Effects of phase noise at both transmitter and receiver on the performance of OFDM systems,” in Proc. 40th Ann. Conf. on Inform. Sci. and Syst., Mar. 2006, pp. 312–316.
[44] D. Banerjee, “PLL performance, simulation, and design,” 4th ed., Indiana: Dog Ear Publishing, 2006.
[45] H.-C. Chang, “Stability analysis of self-injection-locked oscillators,” IEEE Trans. Microw. Theory and Tech., vol. 51, no. 9, pp. 1989–1993, Sept. 2003.
[46] H.-C. Chang, “Phase noise in self-injection-locked oscillators-theory and experiment,” IEEE Trans. Microw. Theory and Tech., vol. 51, no. 9, pp. 1994–199, Sept. 2003.
[47] A. Suarez and F. Ramirez, “Analysis of stabilization circuits for phase-noise reduction in microwave oscillators,” IEEE Trans. Microw. Theory and Tech., vol. 53, no. 9, pp. 2743–2751, Sept. 2005.
[48] T.-P. Wang, Z.-M. Tsai, K.-J. Sun, and H. Wang, “Phase noise reduction of X-band push-push oscillator with second-harmonic self-injection techniques,” IEEE Trans. Microw. Theory and Tech., vol. 55, no. 1, pp. 66–77, Jan. 2007.
[49] Technical Specification Group GSM/EDGE Radio Access Network, 3GPP Standard Release 5, 2001.
[50] L. Sundstrom, M. Haulkner, and M. Johanson, “Quantization analysis and design of a digital predistortion linearizer for RF power amplifier,” IEEE Trans. Veh. Technol., vol. 45, no. 4, pp. 707–719, Nov. 1996.
[51] J.-K. Cavers, “New methods for adaptation of quadrature modulators and demodulators in amplifier linearization circuits,” IEEE Trans. Veh. Technol., vol. 46, no. 3, pp. 707–716, Aug. 1997.
[52] L. Ding, Z. Ma, D.-R. Morgan, M. Zierdt, and G.-T. Zhou, “Compensation of frequency-dependent gain/phase imbalance in predistortion linearization systems,” IEEE Trans. Circuits Syst., vol. 55, no.1, pp. 390–397, Feb. 2008.
[53] L. Anttila, M. Valkama, and M. Renfors, “Frequency-selective I/Q mismatch calibration of wideband direct-conversion transmitters,” IEEE Trans. Circuits Syst. II, Exp. Briefs, vol. 55, no. 4, pp. 359–363, May 2008.
[54] B.-S. Kirei, M.-G. Neag, and M.-D. Topa, “Blind frequency-selective I/Q mismatch compensation using sub-band processing,” IEEE Trans. Circuits Syst. II, Exp. Briefs, vol. 59, no. 5, pp. 302–306, May 2012.
[55] S.-P. Stapleton, G.-S. Kandola, and J.-K. Cavers, “Simulation and analysis of an adaptive predistorter utilizing a complex spectral convolution,” IEEE Trans. Veh. Technol., vol. 41, no. 4, pp. 387–394, Nov. 1992.
[56] M. Faulkner and M. Johansson, “Adaptive linearization using predistortion – experimental results,” IEEE Trans. Veh. Technol., vol. 43, no. 2, pp. 323–332, May 1994.
[57] J. Kim, C. Park, J. Moon, and B. Kim, “Analysis of adaptive digital feedback linearization techniques,” IEEE Trans. Circuits Syst. I, Reg. Papers, vol. 57, no. 2, pp. 345–354, Feb. 2010.
[58] S. Chung, J.-W. Holloway, and J.-L. Dawson, “Open-loop digital predistortion using Cartesian feedback for adaptive RF power amplifier linearization,” in IEEE MTT-S Int. Microw. Symp. Dig., Jun. 2007, pp. 1449–1452.
[59] C.-T. Chen, C.-J. Li, T.-S. Horng, J.-K. Jau, and J.-Y. Li, “Design and linearization of class-E power amplifier for non-constant envelope modulation,” IEEE Trans. Microw. Theory Tech., vol. 57, no. 4, pp. 957-964, Apr. 2009.
[60] C.-H. Lin, H.-H. Chen, Y.-Y. Wang, and J.-T. Chen, “Dynamically optimum lookup-table spacing for power amplifier predistortion linearization,” IEEE Trans. Microw. Theory Tech., vol. 54, no. 5, pp. 2118–2127, May 2006.
[61] H. Ku, and J.-S. Kenney, “Behavioral modeling of nonlinear RF power amplifiers considering memory effects,” IEEE Trans. Microw. Theory Tech., vol. 51, no. 12, pp. 2495–2504, Dec. 2003.
[62] R.-N. Braithwaite, “Digital predistortion system and method for linearizing an RF power amplifier with nonlinear gain characteristics and memory effects,” U.S. Patent 1 908 57, Sept. 2005.
[63] C.-H. Hsiao, C.-T. Chen, T.-S. Horng, and K.-C. Peng, “Direct-conversion transmitter with resistance to local oscillator pulling in non-constant envelope modulation systems,” in IEEE MTT-S Int. Microw. Symp. Dig., May 2011, pp. 1174–1177.
[64] 3GPP2 C.S0024, ver. 2.1: “cdma2000 high rate packet data air interface specification”, 2001.
[65] 3GPP2 C.S0006, ver. 1.0: “Analog signaling standard for cdma2000 spread spectrum systems”, 2002.
[66] TS 25.101(V5.3.0) , 3GPP Standard, 2002.
[67] J. Moon, J. Son, J. Kim, I. Kim, S. Jee, Y.-Y. Woo, and B. Kim, “Doherty amplifier with envelope tracking for high efficiency,” in IEEE MTT-S Int. Microw. Symp. Dig., May 2010, pp. 1086-1089.
[68] C.-H. Hsiao, C.-T. Chen, T.-S. Horng, and K.-C. Peng, “Design of a direct conversion transmitter to resist combined effects of power amplifier distortion and local oscillator pulling,” IEEE Trans. Microw. Theory and Tech., vol. 60, no. 6, pp. 2000–2009, June 2012.