Analog Signal Processing

TL;DR

This paper reviews analog signal processing (ASP) techniques, focusing on phasers and their applications in high-frequency microwave systems, proposing new synthesis methods and discussing future challenges.

Contribution

It introduces novel closed-form synthesis techniques for various phaser types and explores their applications in real-time spectrum analysis and pulse delay systems.

Findings

Enhanced phaser resolution and bandwidth techniques

Development of tunable pulse delay and spectrum sniffer systems

Discussion of future ASP challenges and opportunities

Abstract

Analog signal processing (ASP) is presented as a systematic approach to address future challenges in high speed and high frequency microwave applications. The general concept of ASP is explained with the help of examples emphasizing basic ASP effects, such as time spreading and compression, chirping and frequency discrimination. Phasers, which represent the core of ASP systems, are explained to be elements exhibiting a frequency-dependent group delay response, and hence a nonlinear phase response versus frequency, and various phaser technologies are discussed and compared. Real-time Fourier transformation (RTFT) is derived as one of the most fundamental ASP operations. Upon this basis, the specifications of a phaser resolution, absolute bandwidth and magnitude balance are established, and techniques are proposed to enhance phasers for higher ASP performance. Novel closed-form synthesis techniques, applicable to all-pass transmission-type cascaded Csection phasers, all-pass reflection-type coupled resonator phasers and band-pass cross-coupled resonator phasers are described. Several applications using these phasers are presented, including a tunable pulse delay system, a spectrum sniffer and a realtime spectrum analyzer (RTSA). Finally, future challenges and opportunities are discussed.