Читать книгу Handbook of Microwave Component Measurements - Joel P. Dunsmore - Страница 106

Almost exclusively, modern VNAs use mixers as VNA receivers. The mixers are driven by a fundamental or low‐harmonic‐order LO. This provides a much larger conduction angle for frequency conversion and as such provides a lower noise floor. The trade‐off, of course, is the cost of the LO, which may be due to its increased complexity.