Enter your Control Voltage, Reference Voltage, Timing Capacitor, Timing Resistor, VCO Type, and VCO Gain (Kv) into this VCO Calculator to find your Output Frequency — plus a full breakdown of Frequency in kHz and MHz, Period, and Frequency Deviation.
Output Frequency
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Frequency (kHz)
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Frequency (MHz)
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Period
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Frequency Deviation
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A VCO is an electronic oscillator whose frequency is controlled by an input voltage. It converts a control voltage into a corresponding frequency output, making it essential in PLLs, frequency synthesizers, and modulation circuits.
The relationship depends on the VCO type. Linear VCOs have a direct proportional relationship, while exponential VCOs have a logarithmic response. Higher control voltages typically produce higher output frequencies.
The timing capacitor and resistor primarily determine the frequency range. Smaller capacitance and resistance values increase the operating frequency, while larger values decrease it.
VCO gain (Kv) represents the frequency change per unit voltage change, measured in Hz/V. It determines the sensitivity of the oscillator and is crucial for PLL stability and modulation depth calculations.
Linear VCOs provide constant gain across the control voltage range, ideal for frequency modulation. Exponential VCOs offer wider frequency ranges and are commonly used in synthesizers and musical applications.
Audio VCOs operate from Hz to kHz, RF VCOs from MHz to GHz. Low frequency VCOs (sub-MHz) are used in control systems, while high frequency VCOs serve in communication and radar systems.
Temperature changes affect component values, causing frequency drift. High-quality VCOs use temperature compensation techniques and stable components to minimize drift, typically specified as ppm/°C.
Narrow band VCOs have limited frequency deviation (typically <10%) optimized for stability and low phase noise. Wide band VCOs cover broader frequency ranges but may have higher phase noise and reduced stability.