Kari A.I. Halonen

For four decades the evolution of integrated circuits has followed Moore’s law, according to which the number of transistors per square millimeter of silicon doubles every 18 months. At the same time transistors have become faster, making possible ever-increasing clock rates in digital circuits. This trend seems set to continue for at least another decade without slowing down. Thus, in the near future the processing power of digital circuits will continue to increase at an accelerating pace. For analog circuits the evolution of technology is not as beneficial. Thus, there is a trend to move signal processing functions from the analog domain to the digital one, which, besides allowing for a higher level of accuracy, provides savings in power consumption and silicon area, increases robustness, speeds up the design process, brings flexibility and programmability, and increases the possibilities for design reuse. In many applications the input and output signals of the system are inherently analog, preventing all-digital realizations; at the very least a conversion between analog and digital is needed at the - terfaces. Typically, moving the analog-digital boundary closer to the outside world increases the bit rate across it. In telecommunications systems the trend to boost bit rates is based on - ploying widerbandwidths and a higher signal-to-noise ratio. At the same time radio architectures in many applications are evolving toward software-defined radio, one of the main characteristics of which is the shifting of the anal- digital boundary closer to the antenna.

For four decades the evolution of integrated circuits has followed Moore’s law, according to which the number of transistors per square millimeter of silicon doubles every 18 months. At the same time transistors have become faster, making possible ever-increasing clock rates in digital circuits. This trend seems set to continue for at least another decade without slowing down. Thus, in the near future the processing power of digital circuits will continue to increase at an accelerating pace. For analog circuits the evolution of technology is not as beneficial. Thus, there is a trend to move signal processing functions from the analog domain to the digital one, which, besides allowing for a higher level of accuracy, provides savings in power consumption and silicon area, increases robustness, speeds up the design process, brings flexibility and programmability, and increases the possibilities for design reuse. In many applications the input and output signals of the system are inherently analog, preventing all-digital realizations; at the very least a conversion between analog and digital is needed at the - terfaces. Typically, moving the analog-digital boundary closer to the outside world increases the bit rate across it. In telecommunications systems the trend to boost bit rates is based on - ploying widerbandwidths and a higher signal-to-noise ratio. At the same time radio architectures in many applications are evolving toward software-defined radio, one of the main characteristics of which is the shifting of the anal- digital boundary closer to the antenna.

CMOS Current Amplifiers: Speed versus Nonlinearity is intended as a current-amplifier cookbook containing an extensive review of different current amplifier topologies realisable with modern CMOS integration technologies. The seldom-discussed issue of high-frequency distortion performance is derived for all reviewed amplifier topologies using as simple and intuitive mathematical methods as possible. The topologies discussed are also useful as building blocks for high-performance voltage-mode amplifiers. So the reader can apply the discussed techniques to both voltage- and current-mode analogue integrated circuit design. This book contains application examples with experimental results in three different fields: instrumentation amplifiers, continuous-time analogue filters and logarithmic amplifiers.

CMOS Current Amplifiers: Speed versus Nonlinearity is intended as a current-amplifier cookbook containing an extensive review of different current amplifier topologies realisable with modern CMOS integration technologies. The seldom-discussed issue of high-frequency distortion performance is derived for all reviewed amplifier topologies using as simple and intuitive mathematical methods as possible. The topologies discussed are also useful as building blocks for high-performance voltage-mode amplifiers. So the reader can apply the discussed techniques to both voltage- and current-mode analogue integrated circuit design. This book contains application examples with experimental results in three different fields: instrumentation amplifiers, continuous-time analogue filters and logarithmic amplifiers.

A major advantage of a direct digital synthesizer (DDS) is that its output frequency, phase and amplitude can be precisely and rapidly manipulated under digital processor control. Other inherent DDS attributes include the ability to tune with extremely fine frequency and phase resolution, and to rapidly `hop' between frequencies. These combined characteristics have made the technology popular in military radar and communications systems. In fact, DDS technology was previously applied almost exclusively to high-end and military applications: it was costly, power-hungry, difficult to implement, and required a discrete high speed D/A converter. Due to improved integrated circuit (IC) technologies, they now present a viable alternative to analog-based phase-locked loop (PLL) technology for generating agile analog output frequency in consumer synthesizer applications. It is easy to include different modulation capabilities in the DDS by using digital signal processing (DSP) methods, because the signal is in digital form. By programming the DDS, adaptive channel bandwidths, modulation formats, frequency hopping and data rates are easily achieved. The flexibility of the DDS makes it ideal for signal generator for software radio. The digital circuits used to implement signal-processing functions do not suffer the effects of thermal drift, aging and component variations associated with their analog counterparts. The implementation of digital functional blocks makes it possible to achieve a high degree of system integration. Recent advances in IC fabrication technology, particularly CMOS, coupled with advanced DSP algorithms and architectures are providing possible single-chip DDS solutions to complex communication and signal processing subsystems as modulators, demodulators, local oscillators, programmable clock generators, and chirp generators. The DDS addresses a variety of applications, including cable modems, measurement equipments, arbitrary waveform generators, cellular base stations and wireless local loop base stations. Direct Digital Synthesizers was written to find possible applications for radio communication systems. It will have appeal for wireless and wireline communication engineers, teachers and students.

A major advantage of a direct digital synthesizer (DDS) is that its output frequency, phase and amplitude can be precisely and rapidly manipulated under digital processor control. Other inherent DDS attributes include the ability to tune with extremely fine frequency and phase resolution, and to rapidly `hop' between frequencies. These combined characteristics have made the technology popular in military radar and communications systems. In fact, DDS technology was previously applied almost exclusively to high-end and military applications: it was costly, power-hungry, difficult to implement, and required a discrete high speed D/A converter. Due to improved integrated circuit (IC) technologies, they now present a viable alternative to analog-based phase-locked loop (PLL) technology for generating agile analog output frequency in consumer synthesizer applications. It is easy to include different modulation capabilities in the DDS by using digital signal processing (DSP) methods, because the signal is in digital form. By programming the DDS, adaptive channel bandwidths, modulation formats, frequency hopping and data rates are easily achieved. The flexibility of the DDS makes it ideal for signal generator for software radio. The digital circuits used to implement signal-processing functions do not suffer the effects of thermal drift, aging and component variations associated with their analog counterparts. The implementation of digital functional blocks makes it possible to achieve a high degree of system integration. Recent advances in IC fabrication technology, particularly CMOS, coupled with advanced DSP algorithms and architectures are providing possible single-chip DDS solutions to complex communication and signal processing subsystems as modulators, demodulators, local oscillators, programmable clock generators, and chirp generators. The DDS addresses a variety of applications, including cable modems, measurement equipments, arbitrary waveform generators, cellular base stations and wireless local loop base stations. Direct Digital Synthesizers was written to find possible applications for radio communication systems. It will have appeal for wireless and wireline communication engineers, teachers and students.