Voltage controlled oscillator (VCO) characterizations

Voltage controlled oscillator (VCO) characterizations

Voltage controlled oscillators (VCOs) are oscillators where a defined input signal is controlling the output frequency. They are often used in a closed servo loop, using the phased locked loop (PLL) design as shown in the block diagram. In some cases, they are operated in an open control loop with no feedback for correction.

Phase detector (PD), LPF: Low pass filter, DIV: Frequency divider

The setting accuracy of the frequency is depending on various factors including the linearity of the VCO, the capabilities of the phase detector and the frequency divider. As an analog voltage is controlling the output frequency of the system, a linear translation in the VCO from the input voltage to the output frequency is what designers are aiming for. This is even more important in the case of an open control situation. Frequency versus voltage plots show the principle of the VCO behavior. Additional insight to the provided linearity is provided by tuning slope versus voltage graphs. Obviously a clean, low-noise DC source is required to remove external influences while characterizing the VCO.

The other important characteristic of a VCO is its phase noise level. Classically, phase noise is measured at a certain target frequency for which the VCO needs to be tuned in. When looking across the frequency range, the phase noise level increases as the frequency increases which is an expected behavior. Nevertheless, in highly integrated designs interference can happen leading to unexpected high phase noise at certain frequencies. Looking at the phase noise versus voltage helps to find such unwanted effects.

The R&S®FSPN – unrivalled sensitivity meets high speed

The R&S®FSPN – unrivalled sensitivity meets high speed

Next generation technologies like radar and satellite communication with high data rates call for innovative testing solutions to develop and manufacture RF components. With the launch of the R&S®FSPN, Rohde & Schwarz is adding a new member to the phase noise analyzer portfolio, enabling increased efficiency and reproducibility of phase noise measurements and VCO characterization from lab to production. Watch the video and find out more!

Webinar: Voltage controlled oscillator (VCO) verification

Webinar: Voltage controlled oscillator (VCO) verification

This Webinar is intended for engineers involved with Voltage Controlled Oscillators (VCO) both designing and integrating into systems.

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VCO MEASUREMENTS with R&S FSPN Phase Noise Analyzer

VCO MEASUREMENTS with R&S FSPN Phase Noise Analyzer

Learn more details on voltage controlled oscillator testing incl. a short technical introduction and the most common and the most important measurements made during the VCO characterization process.

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Understanding phase noise fundamentals

Understanding phase noise fundamentals

Learn more about phase noise and its role in oscillators. Get a brief technical introduction to phase noise concepts as well as an overview of how phase noise is measured and reported.

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Understanding voltage controlled oscillators

Understanding voltage controlled oscillators

Learn more about VCOs from design to verification. Get a short technical introduction to voltage controlled oscillators and the most common and the most important measurements made during the VCO characterization process.

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VCO measurements at the push of a button

VCO measurements at the push of a button

Voltage-controlled oscillators (VCO) can be found in almost all RF applications, and their technical parameters significantly influence the quality of the components in which they are used. The R&S®FSWP phase noise analyzer and VCO tester can comprehensively test VCOs at the push of a button.

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