Patent Number: 6,166,533

Title: Frequency spectrum analyzer with high C/N ratio

Abstract: A frequency spectrum analyzer having an improved carrier to noise ration for analyzing frequency spectrum of an input signal. The spectrum analyzer includes a first frequency converter formed of a first frequency mixer, a first IF (intermediate frequency) filter and a first local signal oscillator; a second frequency converter; a third frequency converter formed of a third frequency mixer, a third IF filter and a third local signal oscillator; a frequency divider for dividing a frequency of the first local signal by a factor of N; a frequency multiplier for multiplying a frequency of the third local signal; a fourth frequency mixer which is provided with a divided frequency signal from the frequency divider as a fourth local signal; and a fifth frequency mixer which mixes the input signal to be analyzed and a multiplied frequency signal from the frequency multiplier as a fifth local signal and provides a frequency converted input signal to the fourth frequency mixer; where the fourth frequency mixer mixes the fourth local signal and the frequency converted input signal and provides a resultant IF signal to the third frequency converter.

Inventors: Musha; Hirobumi (Gyoda, JP)

Assignee: Advantest Corp

International Classification: G01R 23/16 (20060101); G01R 23/173 (20060101); G01R 013/24 ()

Expiration Date: 12/26/2017