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Frequency Synthesizers

Here, you can find some links to tutorials for Frequency Synthesizers and Frequency Synthesis Techniques.

By Frequency Synthesizer we usually mean a stable signal generator which can be switced to put out any one of a discrete set of frequencies and whose frequency stability is derived from a standard oscillator. At least three techniques are used for Frequency Synthesis:

  • Direct Synthesis is a popular technique which uses frequency multipliers, frequency dividers and mixers.
  • Indirect Synthesis is based upon phase locked loops (PLLs).
  • Direct Digital Synthesis uses a digital accumulator to produce a staircase sawtooth. A lookup table then changes the sawtooth to a staircase sinusoid and a D-to-A converter provides the analog output.
  • Web Link Tutorial on Direct Digital Synthesis

    This is a technical tutorial from Analog Devices on Direct Digital Synthesis (DDS). It covers almost every aspect starting from fundamentals on DDS technology. 

    Direct digital synthesis (DDS) is a technique for using digital data processing blocks as a means to generate a frequency- and phase-tunable output signal referenced to a fixed-frequency precision clock source. It is considered to be a modern technique and fast becomes an alternative to traditional analog synthesizer techniques.

  • Web Link PLL Fundamentals

    This is a tutorial on PLLs from Analog Devices. Phase-Locked Loop technique is a popular Indirect Frequency Synthesis technique. PLLs are used to generate stable output high frequency signals from a fixed low-frequency signal. Read this tutorial and discover the basics on PLLs.

  • Web Link PLL Performance, Simulation, and Design

    The specific book is written by Dean Banerjee. The writer, first became familiar with PLLs by working for National Semiconductor as an applications engineer. While supporting customers, Dean noticed that there were many repeat questions. Instead of creating the same response over and over, it made more sense to him to create a document, worksheet, or program to address these recurring questions in greater detail and just re-send the file. From all of these documents, worksheets, and programs, this book was born.

  • Web Link Fractional / Integer-N PLL Basics

    Until DSP technology is capable of directly processing and generating the RF signals used to transmit wireless data, PLL will remain a fundamental part of wireless communication systems design.PLLs offer economy in size, power and cost while maintaining good spectral purity. This document from Texas Instruments is to review the theory, design and analysis of PLL circuits.