| 摘要 |
An IQ signal generator comprising a quadrature coupler merged into an amplifier An IQ generator, which may be used in a vector modulator, comprises a quadrature coupler merged into an amplifier. I and Q signals of equal magnitude are derived from ports 2 and 3 when the single-ended input Vin is applied to the gate of the common source input transistor M1. The quadrature coupler may comprise a lumped element configuration L,C/2, which provides a compact circuit design, or an equivalent distributed component configuration such as a branch line coupler (figure 4). The circuit provides good IQ amplitude matching, less I/Q imbalance, no losses, and less noise than prior art IQ generators. The optical common-gate output transistors M3,M4 provide configuration which improves isolation of the generator outputs. |
