| 摘要 |
PROBLEM TO BE SOLVED: To shift frequency before transmission in radiotelephony. SOLUTION: The frequency converter supplies an output signal having radio frequency RF equal to the difference of the frequency FLO of a signal OS generated in an oscillator VCO and the frequency FI of an input signal IS. The frequency converter has two orthogonal modules QM1, QM2 separating the signal from the oscillator VCO and the input signal IS into orthogonal two components (LO1, LO2) and (FI1, FI2), two mixers MX1, MX2 multiplying the components obtained two by two and a combination means recombining output signals RS1, RS2 from the mixers MX1, MX2. Excellent performance is provided regarding noises and gains, and the frequency converter internally conducting the superior elimination of image frequency, making linearity better than a known converter is obtained. |
