CMOS Fractal Oscillator Design for Frequency-Shift Keying Modulation Using Multiplexers

Abstract

A new version of the well-known FSK (Frequency-Shift Keying) modulation technique for telecommunication system was proposed and verified. A simple form of ring oscillator with three inverters was adopted for the basic frequency generator. The frequency shift was realized using a ring oscillator composed of nine inverters. CMOS multiplexers were used to select one of two different oscillators, i.e., to shift between two different frequencies. Simulations were performed for the verification.

Ring-Oscillator Type Multi-Chip Clock Signal Synchronization Technique with In-Phase Clock Bus Lines

“…In a triangular layout, having one inverter at each node, this basic ring oscillator can be expanded and spread out in two dimensional, yielding a Cellular Oscillator Network (CON) [2]. In simulations and tests, this CON has been proven to have robustness against temperature and voltage gradient in a single chip [7][8]. At the same time, by using a different cell that is composed of nine inverters, instead of original three inverters, this CON is proven to function a frequency modulator as well [9][10].…”

“…Notice here that each branch is shared adjacent three triangles, 10-8-12, 11-9-10, and 12-7-11, composing four ring oscillators with nine inverting amplifiers. Likewise, if each and every branch of this basic triangle is shared with an adjacent cell, this structure can spread out infinitely in 2D in a fractal mode as seen in Figure 1 [7][8][9][10]. We named this structure Cellular Oscillator Network (CON), and if we use a simple inverter, with one PMOS and one NMOS transistors, the simplest form of CON can be designed and implemented easily in today's well-established CMOS technology.…”