關于有源晶振的參數規格，大部分采購可能只認識比較主要的封裝尺寸，類型，頻率，精度，電源電壓之類的，但其實振蕩器詳細的參數并止這些。而是多達十幾種甚至是二十幾種，VCXO是壓控晶體振蕩器的英文簡稱，具有電壓控制性能，因此被命名為壓控晶振，適合用到無線通信，飛機船舶，工業儀器儀表，軍用，全球導航定位系統，智能手機等產品。以下是VCXO晶振相關的詳細的參數及其含義。

PPM：“百萬分率”的縮寫，一種用于指定允許值的計算方法，晶體或石英晶體振蕩器的頻率偏差。也可以被視為“ppm”。
相位噪聲：一個相位調制邊帶的功率密度與總信號之比。目錄中的所有相位噪聲數據歸一化為一赫茲等效帶寬。
負載（扇出）：振蕩器驅動其他設備的容量。 TTL器件以可驅動的門數指定;即10個TTL門。 CMOS輸出以pF指定;即15 pF或50 pF負載。
啟用/禁用：啟用/禁用引腳類似于開/關開關。啟用/禁用時為低電平或邏輯0會導致設備不振蕩。使能/禁止引腳上的“高電平”或邏輯1允許單元正常工作（使能），產生指定的輸出。
偏差：數量與其名義價值的差異。出于目的，頻率與標稱頻率或指定頻率不同的量。
下降時間：信號從邏輯'1'變為邏輯'0'所需的時間。
頻率范圍：晶振可以制造的頻率范圍，對規格的影響最小。
線性度：偏離控制電壓與輸出頻率的直線關系。
振蕩器：在其輸出端產生特定頻率的交流電的電路或設備。
老化：振蕩器輸出頻率的系統平均變化僅作為時間的函數。老齡化不包括環境變化的影響。
可移動性：壓控晶體振蕩器的頻移是控制電壓的函數。
上升時間：信號從邏輯'0'變為邏輯'1'所需的時間。
穩定性：由溫度變化引起的振蕩器頻率的變化，以所需的振蕩器頻率為參考。
啟動：從瞬時電壓施加到振蕩器的時間，直到振蕩器輸出穩定。
預熱：振蕩器頻率在幾小時后穩定在給定的頻率容差范圍內所需的時間。
三態：三態選項類似于啟用/禁用。當pin1上有一個“邏輯1”（例如5 Vdc）時，該單元正常工作“啟用”，產生指定的輸出（例如TTL）。當引腳被禁止時，“邏輯0”（ex 0 Vdc）進入高阻抗或三態模式。三態模式允許客戶從電路中移除石英振蕩器而無需將其物理移除。用于調整，測試或解決他們的電路板問題。
對稱性：信號處于邏輯高電平的每個周期的百分比。該參數在指定的電壓閾值或輸出波形幅度的百分比下測量。
英文版：
Aging: A systematic average change of an oscillator’s output frequency as a function only of time. Aging does not include effects of changing environments.
Deviation: The amount by which a quantity differs from its nominal value. For purposes, the amount by which a frequency differs from the nominal or specified frequency.
Enable/Disable: The enable/disable pin is similar to an on/off switch. A low or logic 0 on the enable/disable causes the unit not to oscillate. A “high” or logic 1 on the enable/disable pin allows the unit to work as normal (enabled) producing the specified output.
Fall Time: the time required for a signal to go from Logic ‘1’ to logic ‘0’.
Frequency Range: The range of frequencies over which an oscillator can be fabricated with minimal impact on specifications.
Linearity: The departure from a straight line relationship of control voltage to output frequency.
Oscillator: A circuit or device that produces an alternating current of a specific frequency at its output terminals.
Phase Noise: The ratio of the power density of one phase modulation sideband to the total signal. All phase noise data in the catalog are normalized to a one Hertz equivalent bandwidth.
Load (Fan out): The capacity of the oscillator to drive other devices. TTL devices are specified in the number of gates that can be driven; i.e., 10 TTL gates. CMOS outputs are specified in pF; i.e. 15 pF or 50 pF loads.
PPM: The abbreviation for “Parts Per Million,” a method of calculation used to specify the permissible
frequency deviation of a crystal or oscillator. May also be seen as “ppm”.
Pullability: The frequency shift of a VCXO as a function of control voltage.
Rise Time: The time required for a signal to go from Logic ‘0’ to logic ‘1’.
Stability: The change in oscillator frequency, referenced to the desired oscillator frequency, caused by temperature change.
Start-Up: The period from the instant voltage is applied to the oscillator until the oscillator output is stabilized.
Symmetry: The percentage of each period that a signal is in logic high. This parameter is measured at a specified voltage threshold or at a percentage of the output waveform amplitude.
Tri-state: The tri-state option is similar to the Enable/Disable. When you have a “logic 1” (ex 5 Vdc) on pin1,the unit works as normal “enabled” producing the specified output (ex TTL). When the pin is disabled, “logic 0” (ex 0 Vdc) it goes into high impedance or tristate mode. The tristate mode allows the customer to remove the oscillator from their circuit without physically removing it. Useful for tuning, testing or trouble shooting their board.
Warm-Up: The time required for an oscillator’s frequency to settle to within a given tolerance of the frequency several hours later.

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