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    Electronic Components
    1. HOME
    2. Electronic Components
    3. Timing Devices (Crystal Unit / Ceramic Resonator)
    4. Crystal Units
    5. Basic Knowledge of Crystal Units
    6. Basic Knowledge of How to Measure the Oscillation Frequency
    Crystal Units

    Crystal UnitsBasic Knowledge of How to Measure the Oscillation Frequency

    Oscillating frequency

    Oscillating frequency is actual frequency of oscillation circuit which works with crystal.
    It is mainly determined by cristal unit and influenced by MCU, external load capacitance, stray capacitance of PCB and so on.

    Measurement

    Measurement method

    Oscillation frequency is calculated by below formula.
    fL : Load resonant frequency, fr : Resonant frequency, Cs : Load capacitance, C0, C1 : Equivalent circuit contents

    Formula

    Measurement method 1

    1. Measurement equipment and device
      • Oscillation circuit
      • Frequency counter
      • Amplifier (or oscilloscope with output signal)
      • Probe
    2. Prepare measurement equipment as shown in figure below. Please expand the Y-axis range of oscilloscope as wide as possible.
    3. Bring probe to oscillation circuit as close as possible.
    4. Read frequency on frequency counter.
    Oscillation circuit:Frequency measurement by counter

    Note

    • Please do not contact probe to oscillation circuit. Actual oscillation frequency becomes low by input capacitance of probe.
    • Please pay attention that accuracy of frequency shown in oscilloscope would not be enough.
    • Please pay attention for sampling rate or number of averaging of degital oscilloscope due to quantization error.

    Measurement method 2

    1. Measurement equipment and device
      • Oscillation circuit
      • Spectrum analyzer
      • Antenna (Coaxial cable could be used as antenna)
    2. Prepare measurement equipment as shown in figure below.
    3. Bring antenna to oscillation circuit as close as possible.
    4. Read peak frequency of response in spectrum analyzer.
    Oscillation circuit:Frequency measurement by spectrum analyzer

    Note

    • Please do not contact antenna to oscillation circuit.
    • Please measure response with narrow span of spectrum analyzer for accurate measurement.

    Notes

    It is important to measure frequency without any contact to oscillation circuit to prevent influence of probe and so on. Oscillation frequency will shift if probe touches to oscillation circuit by its capacitance.

    Basic Knowledge of Crystal Units

    Crystal Units: Basic Knowledge of Technical Terms

    We describe the technical terms frequently used with crystal units such as the resonance frequency, equivalent circuits, and pulling sensitivity.
    Basic Knowledge of How to Measure the Oscillation Margin

    Explains the oscillation margin and how to calculate (determine) it, as well as how to measure or make a quick check of the negative resistance, etc.
    Basic Knowledge of How to Measure the Drive Level

    Describes the drive level, explains how to calculate (determine) it, and gives an example of how to measure drive level, etc.
    Basic Knowledge of How to Measure the Oscillation Amplitude

    Describes the oscillation amplitude, shows what is required to measure it, and presents notes on things to consider, etc.
    The Advantages of Murata's Crystal Units

    We describe the strengths of Murata's crystal units, which use our world-first unique packaging technology.
    Selection Guide

    We describe selected products most suitable for your application among ceramic resonators (CERALOCK) and crystal units.
    Support information by applications

    We provide support information by application for ceramic resonators (CERALOCK) and crystal units.
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    1. Electronic Components
    2. Timing Devices (Crystal Unit / Ceramic Resonator)
    3. Crystal Units
    4. Basic Knowledge of Crystal Units
    1. HOME
    2. Electronic Components
    3. Timing Devices (Crystal Unit / Ceramic Resonator)
    4. Crystal Units
    5. Basic Knowledge of Crystal Units
    6. Basic Knowledge of How to Measure the Oscillation Frequency
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