Automated calibration of modulated frequency synthesizers

In recent years, there has been considerable interest in highly integrated, low power, portable wireless devices. There are three primary areas to be addressed when higher performance and lower power is desired. The first area is the device technology. Scaling of devices has realized steady improvements for many years. The second area is improved circuit design techniques. The final area is at the architectural level. This monograph focuses on the problem of low power GFSK/GMSK modulation and presents an architectural approach for improved performance. The new architecture is a modulated S-D fractional-N frequency synthesizer. The key innovation is an automatic calibration technique, which operates in the background. The availability of the calibration circuit makes high data rate, low power modulation possible.
From the Foreword: "The key contribution of the work presented in this monograph is a technique for in service automatic calibration of the modulated frequency synthesizer by ensuring that the digital emphasis filter and analog loop filter characteristics are matched. The automatic calibration circuit operates while the transmitter is in service and compensates for process and temperature variation. GFSK and 4-GFSK modulation was demonstrated at data rates of 2.5 Mb/s and 5 Mb/s respectively at an RF output carrier frequency of 1.8 GHz. ... In addition, he presents some valuable tools for the practicing engineer in this field." by Charles G. Sodini

List of Figures. List of Tables. Foreword by Charles G. Sodini. Acknowledgments. 1: Introduction. 1.1 Outline. 1.2. Choice of Modulation Affects Battery Life. 1.3. Classes of Modulation. 1.3.1. Linear Modulation. 1.3.2. Constant Envelope Modulation. 1.4. GFSK and GMSK. 1.5. Coherent Versus Noncoherent Demodulation. 1.5.1. Modulator Requirements for Coherent Detection. 1.6. Chapter 1 Summary. 2: Architectures. 2.1. Direct VCO Modulation. 2.2. Quadrature Modulator. 2.3. Open Loop Modulation with PLL Tuning. 2.4. Modulated Fractional-N Synthesizer. 2.5. Calibrated Synthesizer Architecture. 2.6. Chapter 2 Summary. 3: System Requirements. 3.1. Total Phase Error Variance. 3.2 Chapter 3 Summary. 4: Automatic Calibration System. 4.1. PLL Mismatch Model. 4.2. The Gain Error Detector. 4.3. Track and Hold Modification to the Error Detector. 4.4. Simulated Gain Error Detector Performance. 4.5. Carrier Phase Tracking. 4.5.1. Sources of Carrier Phase Error. 4.5.2. Effect of Phase Offset and Drift on the Gain Error Detector. 4.5.3. Digital Phase Locked Loop Addition. 4.6. Complete Gain Error Detector. 4.7. Acquisition Range and Digital Coarse Calibration. 4.8. Application to Other Architectures. 4.9. Chapter 4 Summary. 5: Implementation Details. 5.1. Discrete Prototype. 5.1.1. Charge Pump and Loop Filter. 5.1.2. VCO. 5.1.3. RF Output Filter and Buffer. 5.1.4. RF Phase Quantizer. 5.1.5. Quadrature Sampler Approach. 5.1.6. Board Level Phase Quantizer Circuit Details. 5.1.7. Digital Calibration DAC. 5.1.8. Multimodulus Divider. 5.1.9. Reference Oscillator. 5.1.10. Digital Signal Processing. 5.2. Integrated Circuit Process Technology. 5.2.1. Varactor. 5.2.2. Bondwire Inductors. 5.3. RF Phase Quantizer. 5.3.1. RF Phase Quantizer Circuit Details. 5.3.2. Phase Quantizer Comments. 5.3.3. RF Interconnect. 5.4. Digital Building Blocks. 5.4.1. Flip-Flops. 5.4.2. Adders. 5.5. Reference Error Filter. 5.5.1. Decimator Design. 5.5.2. Discrete Time Filter Approximation. 5.5.3. Digital Filter Architectures. 5.5.4. SPT Approximation. 5.6. Digital Phase Locked Loop and Phase Error Measurement. 5.6.1. DPLL Loop Dynamics. 5.6.2. Carrier Phase Detector with Track and Hold. 5.6.3. Upsampler. 5.7. Gain Control Multiplier and Error Amp. 5.8. 1.8 GHz VCO. 5.9. Main Synthesizer. 5.10. &Dgr,-&Sgr, Modulator. 5.11. Chapter 5 Summary. 6: Experimental Results. 6.1. Discrete Prototype Results. 6.1.1. Discrete Prototype GFSK/GMSK Eye Pattern and Spectrum. 6.1.2. Discrete Prototype RF Phase Quantizer. 6.2. Integrated Circuit Test Environment. 6.3. Automatic Calibration Results. 6.3.1. GFSK/GMSK Eye Pattern and Spectrum. 6.3.2. 4 Level GFSK Eye Pattern and Spectrum. 6.3.3. Calibration Dynamics. 6.4. Power Consumption. 6.5. VCO performance. 6.6. RF Phase Quantizer. 6.7. Summary. 7: Summary and Conclusions. 7.1. Recommendations for Future Work. Appendices: Tools. A.1: Simulation Tools. A.2: Test Setup Tools. A.3: Typesetting Tools. A.4: Miscellaneous. Index.