Digital signal processing - up to microwave frequencies

Abstract

Digital logic integrated circuits are advancing toward ever higher speeds of operation. Clock frequencies already exceed 1 GHz in some Si CMOS-based consumer products, and even higher speeds are attainable in specialized technologies, such as those based on GaAs, InP, and SiGe bipolar and field-effect transistors. Digital approaches may be used to carry out a variety of functions important in microwave systems, including signal generation, filtering, and frequency conversion. The digital implementation provides a variety of potential benefits, including lack of sensitivity to aging and component inaccuracies, flexibility, and programmability. The dynamic range and degree of nonlinearity can be specified by design. Signal storage and memory functions are easily accomplished. Single-chip integration of digital and microwave systems are also facilitated. The application of digital techniques in domains previously considered to be analog is an important ongoing technology thrust, which may be expected to accelerate. Critical interfaces between the digital and analog domains are provided by analog-to-digital converters, digital-to-analog converters, and fractional-frequency synthesizers. This paper reviews the prospects of digital techniques for microwave systems, and briefly describes the state-of-technology and future possibilities. Index Terms-Analog-to-digital conversion, digital signal processing, digital-to-analog conversion, high-speed digital integrated circuits. I. INTRODUCTION S IGNAL processing (including amplification, filtering, frequency generation, frequency conversion, and modulation) at microwave frequencies has traditionally been carried out with analog circuits. However, digital circuits are steadily advancing in capabilities. The technology advances promise to allow digital techniques to be used at frequencies well into the microwave region.

Extension of the range of resonator scanning spectrometer into submillimeter band and some perspectives of its further developments

“…Useful review of existing status and perspectives of digital signal processing including DFD, DDS, etc. is presented in [14] and references therein. Description of separate elements necessary for construction of aforementioned system with high parameters one can find, e.g., in [14][15][16].…”

“…is presented in [14] and references therein. Description of separate elements necessary for construction of aforementioned system with high parameters one can find, e.g., in [14][15][16]. Situation in this field is changing rapidly, and references mentioned reflect rather lower estimations of necessary parameters.…”

Interrogation of a linearly chirped fiber Bragg grating sensor with high resolution using a linearly chirped optical waveform

“…To increase the speed, interrogation of FBG sensors can be implemented based on microwave photonic (MWP) techniques to convert the wavelength shift in the optical domain to the amplitude or frequency change of a microwave signal in the electrical domain [10,11]. Since the amplitude or frequency of a microwave signal can be estimated at a high speed using a digital signal processing (DSP) unit [12], an MWP-based FBG sensor can provide ultra-fast sensing. For an MWP-based FBG sensor, if the Bragg wavelength shift is converted to the amplitude change of a microwave signal, the sensing resolution is still poor due to the optical power fluctuations in the system [13].…”

Analysis of distortion in pulse modulation converters for switching radio frequency power amplifiers

“…The new structure requires a bandpass filter at the output but eliminates the need for most other analog components such as digital to analog converters (DACs), reconstruction filters, the local oscillator and the quadrature modulator. It also provides the possibility of integrating both the digital and microwave sections on to a single chip [5].…”