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6.5: Oscilador controlado por voltaje (VCO)

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    85265
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    Como su nombre lo indica, un voltaje de control establece la frecuencia de la salida de un VCO. El diagrama de bloques de un VCO se muestra en la Figura 6.4.8 (a) donde una señal de entrada que varía lentamente\(v_{i}\),, determina la frecuencia\(f_{0}\),, de la señal producida por un oscilador. Esto generalmente se logra variando la capacitancia de un diodo varactor en un resonador.

    Una de las características importantes de un VCO es la curva de sintonización, que traza la frecuencia de salida\(f_{0}\) contra el voltaje de sintonización aplicado\(v_{i}\) como se muestra en la Figura 6.4.8 (b). Idealmente, la curva de afinación es una línea recta, pero en la práctica tiene forma y el rango real sobre el que se usa el VCO es menor que el rango completo soportado. La propiedad de sintonía se describe por la constante de afinación,

    \(f_{0}\)
    \(\text{GHz}\)
    \(f_{\text{BW}}\)
    \(\text{MHz}\)
    \(P_{\text{RF}}\)
    \(\text{dBm}\)
    \(P_{\text{DC}}\)
    \(\text{mW}\)
    \(f_{m}\)
    \(\text{MHz}\)
    \(\mathcal{L}(f_{m})\)
    \(\text{dBm/Hz}\)
    \(\mathcal{L}(1\text{ MHz})\)
    \(\text{dBm/Hz}\)
    \(\text{FOM}_{1}\)
    \(\text{dBm/Hz}\)
    \(\text{FOM}_{2}\)
    \(\text{dBm/Hz}\)
    Referencia
    \ (f_ {0}\)\(\text{GHz}\) “>\(4.92\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(770\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “>\(0\) \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(150\) \ (f_ {m}\)\(\text{MHz}\) “>\(1\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-128\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “> \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-106\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “>\(-157\) Híbrido SiG HBT [13]
    \ (f_ {0}\)\(\text{GHz}\) “>\(5.05\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(500\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “>\(0\) \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(150\) \ (f_ {m}\)\(\text{MHz}\) “>\(1\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-130\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “> \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-106\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “>\(-155\) Híbrido SiGe HBT [13]
    \ (f_ {0}\)\(\text{GHz}\) “>\(5.16\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(229\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “>\(-0.43\) \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(24\) \ (f_ {m}\)\(\text{MHz}\) “>\(1\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-111\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “> \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-98\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “>\(-136\) Ingap/GaAs HBT [14]
    \ (f_ {0}\)\(\text{GHz}\) “>\(11.5\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(550\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “>\(9\) \ (P_ {\ texto {DC}}\)\(\text{mW}\) “> \ (f_ {m}\)\(\text{MHz}\) “>\(0.1\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-91\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “>\(-111\) \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “> \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “>\(-138\) MESFET de GaAs [15]
    \ (f_ {0}\)\(\text{GHz}\) “>\(9.33\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(440\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “>\(3.3\) \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(30.5\) \ (f_ {m}\)\(\text{MHz}\) “>\(1\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-102\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “> \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-87\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “>\(-128\) GaN HEMT [16]
    \ (f_ {0}\)\(\text{GHz}\) “>\(6.40\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(150\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “>\(5.5\) \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(173\) \ (f_ {m}\)\(\text{MHz}\) “>\(0.1\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-105\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “>\(-125\) \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-85\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “>\(-127\) SiGe HBT [17]
    \ (f_ {0}\)\(\text{GHz}\) “>\(5.94\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(166\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “>\(-4.0\) \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(8.1\) \ (f_ {m}\)\(\text{MHz}\) “>\(1\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-110\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “> \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-94\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “>\(-134\) CMOS IC [18]
    \ (f_ {0}\)\(\text{GHz}\) “>\(4.87\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(70\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “>\(-4.0\) \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(4.8\) \ (f_ {m}\)\(\text{MHz}\) “>\(1\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-131\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “> \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-124\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “>\(-149\) Ganancia/GaAs HBT [19]
    \ (f_ {0}\)\(\text{GHz}\) “>\(5.38\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(120\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “>\(-4.0\) \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(12.8\) \ (f_ {m}\)\(\text{MHz}\) “>\(1\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-127\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “> \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-108\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “>\(-148\) Ganancia/GaAs HBT [20]
    \ (f_ {0}\)\(\text{GHz}\) “>\(5.29\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(270\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “>\(-5.5\) \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(14\) \ (f_ {m}\)\(\text{MHz}\) “>\(1\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-106\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “> \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-94\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “>\(-130\) SiGe HBT [21]
    \ (f_ {0}\)\(\text{GHz}\) “>\(2.17\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(385\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “>\(11.2\) \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(1.9\) \ (f_ {m}\)\(\text{MHz}\) “>\(0.6\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-120\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “>\(-125\) \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-122\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “>\(-150\) CMOS IC [22]
    \ (f_ {0}\)\(\text{GHz}\) “>\(1.72\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(262\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “>\(-11.5\) \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(75\) \ (f_ {m}\)\(\text{MHz}\) “>\(1\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-129\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “> \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-111\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “>\(-153\) Ingap/GaAs HBT [23]
    \ (f_ {0}\)\(\text{GHz}\) “>\(4.80\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(1200\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “>\(4.8\) \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(36\) \ (f_ {m}\)\(\text{MHz}\) “>\(1\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-111\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “> \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-95\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “>\(-141\) SiGe BiCMOS IC [24]
    \ (f_ {0}\)\(\text{GHz}\) “>\(9.35\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(2500\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “>\(18.3\) \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(570\) \ (f_ {m}\)\(\text{MHz}\) “>\(1\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-110\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “> \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-82\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “>\(-144\) GaN/SiC PhEMT [25]
    \ (f_ {0}\)\(\text{GHz}\) “>\(1.72\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(261\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “>\(-10.3\) \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(55\) \ (f_ {m}\)\(\text{MHz}\) “>\(1\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-120\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “> \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-103\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “>\(-144\) Ingap/GaAs HBT [26]
    \ (f_ {0}\)\(\text{GHz}\) “>\(4.17\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(70\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “>\(-6.1\) \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(102\) \ (f_ {m}\)\(\text{MHz}\) “>\(1\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-116\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “> \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-96\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “>\(-134\) Ganancia/GaAs HBT [27]
    \ (f_ {0}\)\(\text{GHz}\) “>\(2.09\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(360\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “> \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(20.8\) \ (f_ {m}\)\(\text{MHz}\) “>\(3\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-140\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “>\(-130\) \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-117\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “> CMOS VCO [28]
    \ (f_ {0}\)\(\text{GHz}\) “>\(1.53\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(330\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “> \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(21.2\) \ (f_ {m}\)\(\text{MHz}\) “>\(0.6\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-133.5\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “>\(-138\) \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-125\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “> CMOS VCO [29]
    \ (f_ {0}\)\(\text{GHz}\) “>\(4.89\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(650\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “> \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(22\) \ (f_ {m}\)\(\text{MHz}\) “>\(1\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-124\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “> \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-111\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “> CMOS VCO [30]
    \ (f_ {0}\)\(\text{GHz}\) “>\(1.85\) \ (f_ {\ text {BW}}\)\(\text{MHz}\) “>\(280\) \ (P_ {\ texto {RF}}\)\(\text{dBm}\) “> \ (P_ {\ texto {DC}}\)\(\text{mW}\) “>\(20\) \ (f_ {m}\)\(\text{MHz}\) “>\(3\) \ (\ mathcal {L} (f_ {m})\)\(\text{dBm/Hz}\) “>\(-143\) \ (\ mathcal {L} (1\ texto {MHz})\)\(\text{dBm/Hz}\) “>\(-133\) \ (\ text {FOM} _ {1}\)\(\text{dBm/Hz}\) “>\(-120\) \ (\ text {FOM} _ {2}\)\(\text{dBm/Hz}\) “> CMOS VCO [30]

    Tabla\(\PageIndex{1}\): Comparación de VCO RF. El ruido de fase es el peor de los casos sobre el rango de sintonización; la potencia de salida de RF Todos los osciladores son híbridos a menos que se indique por IC, denotando un circuito integrado. Si no\(f_{m}\) es así\(1\text{ MHz}\), entonces se supone una\(1/f^{2}\) dependencia para que el ruido de fase calcule el ruido de fase en\(1\text{ MHz}\). Los VCO CMOS son VCO en cuadratura que producen dos salidas\(90^{\circ}\) separadas. Después [13] con corregido\(\text{FOM}_{1}\). (\(P_{\text{ref}} = 1\text{ mW},\: f_{\text{ref}} = 1\text{ MHz}\).)

    que también se conoce como la ganancia de afinación,\(K_{0}\). Este es el cambio en la frecuencia de oscilación para un cambio en el voltaje de control. Para el VCO en la Figura 6.4.2,

    \[\label{eq:1}K_{0}=\frac{\Delta f_{0}}{\Delta v_{i}} \]

    El rendimiento de un VCO de microondas es uno de los aspectos más competitivos del diseño de RF, ya que cada reducción de decibelios en el ruido de fase aumenta enormemente el rendimiento general del sistema. Un VCO de alto rendimiento también relaja las demandas de otros componentes del sistema. Mientras que FOM\(_{1}\) (ver Ecuación (6.4.2)) sirve como métrica útil para comparar VCO, otro FOM con ponderación de ancho de banda proporciona una mejor comparación del rendimiento de diferentes VCO. Esta segunda cifra de mérito es [13]

    \[\label{eq:2}\text{FOM}_{2}=\mathcal{L}(f_{m})-10\log\left(\frac{1\text{ MHz}}{f_{m}}\right)^{2}-10\log\left(\frac{f_{\text{BW}}}{f_{\text{ref}}}\right) \]

    donde\(f_{\text{BW}}\) está el ancho de banda de sintonización y\(f_{\text{ref}}\) es el ancho de banda de referencia, tomado aquí como\(1\text{ MHz}\). Nuevamente se hace referencia al ruido de fase\(1\text{ MHz}\). Una serie de osciladores de microondas de alto rendimiento se comparan en la Tabla\(\PageIndex{1}\). El mejor ruido de fase que normalmente se puede lograr mediante VCO que operan en el\(1– 10\text{ GHz}\) rango es\(−130\text{ dBc/Hz}\) en\(1\text{ MHz}\). Esto se compara con el componente de ruido de fase del ruido blanco a temperatura estándar, que se mostró en la Sección 4.2.2 como ser\(−177\text{ dBc/Hz}\).


    6.5: Oscilador controlado por voltaje (VCO) is shared under a not declared license and was authored, remixed, and/or curated by LibreTexts.