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A multimode transceiver system requires up and down conversion that is made possible with the use of a multiple frequency band voltage-controlled oscillators (VCO’s). Unlike the output of a single frequency oscillator, a VCO’s frequency output is varied over a frequency range controlled by a variable DC control voltage at its input. The exact output frequency is related to this input DC control voltage.


There are 2 types of VCO’s—harmonic oscillators and relaxation oscillators.


The output signal of the harmonic oscillator has a sinusoidal waveform similar to that of both crystal and tank oscillators, while the relaxation has a sawtooth or triangular waveform. This provides a variety of operational techniques.


VCO’s are often used for function generators, for frequency synthesizers in communication circuits, in electronic jamming equipment, in phase locked loop signal sources, and for the production of different types of noise generation test equipment.


Electronics that operate in several modes, and switch between receiving signals and transmitting signals, require signal sources with low phase noise behavior such as a stable free running oscillator. The problem with these oscillators is that there are trade-offs between the phase noise and power consumption. If phase noise is reduced, for example, power consumption and coverage are increased.


A stable VCO is essential in communication systems where phase lock conditions need to be maintained, and the integrity of transmission data is insured. In today’s mature frequency generation systems, multi-band signal sources are required to cover their bandwidth demands. This is where a dual mode oscillator would be useful. It generates two signals, each at a different frequency, effectively satisfying the bandwidth requirement. The two signals need to be harmonically related.


It is also important that multiband VCO blocks are designed today to be re-configurable in preparation for migration to future, newer communication standards. As the technology of wireless devices evolves with higher data rates, VCO’s will need to be reconfigured.


It is important for the next generation of wireless communication systems, such as 5G to be frequency agile and cover the several different global standards. This is only possible if they’re able to dynamically and seamlessly span multiple frequency bands. Thus, the future need for multimode frequency generation techniques.


These techniques must also support improved phase noise performance when operating in dual mode over the band.


VCOs from Synergy Microwave Corporation

Synergy Microwave Corporation (SMC) probably has the best oscillators in the market. SMC offers over 250 different VCO’s without counting those that are custom produced for very specific requirements. The VCO’s vary in frequency, max tuning voltage, DC Bias, Max DC Bias, and Typical phase Noise. These VCOs exhibit high performance and have frequencies ranging from 10 MHZ up to 18 GHZ. The VCO’s feature exceptionally low phase noise performance, and have optimized frequency ranges of up to 3:1 bandwidth. The resonator construction can be either planar, ceramic or SAW and they are available in miniature and small size surface mount packages or with coaxial connectors.



We at Peninsula Technical Sales are happy to answer any questions you may have regarding VCOs or other electronic components. Please call us at 650-965-3636 or visit our website at or e-mail us at We look forward to hearing from you.




Peninsula Technical Sales represents electronic equipment manufacturers and is proud to offer our services online and to the following cities and their surrounding areas: San Francisco, Santa Clara, San Jose, Fremont, Sacramento, Milpitas, and Santa Rosa.