Suppression of Spurious Signals at Outputs of Voltage-Controlled Oscillators

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Suppression of Spurious Signals at Outputs of Voltage-Controlled Oscillators

Popis výsledku v původním jazyce

Voltage-controlled oscillators (VCOs) belong to the most frequently used RF and microwave components. Embodied in PLL based local oscillators (LOs), they are part of nearly all radio devices. Since in these applications the LOs drive non-linear multiplying or mixing stages, their wideband output spectrum must be as clean as possible. In case of microwave VCOs, this often also refers to a sub-harmonic f0/2 frequency component. The f0/2 spurious signal is caused by presence of the f0/2 frequency output in a VCO structure. This frequency component can be removed by a standard microwave filter connected directly at the LO output. But this solution can lead to finding out that filter attenuation is substantially lower than expected. This paper shows that this effect is to a substantial degree caused by the fact that the VCO output is usually well matched at f0 but can be highly mismatched at f0/2. The paper also shows that this problem can be solved relatively simply and effectively by use of an additional transmission line section that ensures filter operational attenuation to be even substantially higher than the nominal value. The same design procedure can be used in other similar cases.

Název v anglickém jazyce

Suppression of Spurious Signals at Outputs of Voltage-Controlled Oscillators

Popis výsledku anglicky

Voltage-controlled oscillators (VCOs) belong to the most frequently used RF and microwave components. Embodied in PLL based local oscillators (LOs), they are part of nearly all radio devices. Since in these applications the LOs drive non-linear multiplying or mixing stages, their wideband output spectrum must be as clean as possible. In case of microwave VCOs, this often also refers to a sub-harmonic f0/2 frequency component. The f0/2 spurious signal is caused by presence of the f0/2 frequency output in a VCO structure. This frequency component can be removed by a standard microwave filter connected directly at the LO output. But this solution can lead to finding out that filter attenuation is substantially lower than expected. This paper shows that this effect is to a substantial degree caused by the fact that the VCO output is usually well matched at f0 but can be highly mismatched at f0/2. The paper also shows that this problem can be solved relatively simply and effectively by use of an additional transmission line section that ensures filter operational attenuation to be even substantially higher than the nominal value. The same design procedure can be used in other similar cases.

Druh

D - Stať ve sborníku

CEP obor

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OECD FORD obor

20201 - Electrical and electronic engineering

Projekt

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Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

Proceedings of the International Student Scientific Conference Poster – 22/2018

ISBN

978-80-01-06428-3

ISSN

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e-ISSN

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Počet stran výsledku

5

Strana od-do

1-5

Název nakladatele

Czech Technical University in Prague

Místo vydání

Praha

Místo konání akce

Praha

Datum konání akce

10. 5. 2018

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

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