sophiante
Junior Member level 3
Semiconductor manufacturers sometimes suggests circuit arhcitecture for their IC's. In the case of I/Q modulators one can see two approaches:
1. Direct conversion where the quadrature IC modulates a VCO on the output frequency.
2. An intermidiate frequency VCO in the range 50-250MHz is modulated and then upconverted to output frequency.
Number 1 is obviously much simpler (less filtering) - that is why I suspect it to have some serious drawbacks!
Is there a short answer to why these two approaches both are used?
Jan
1. Direct conversion where the quadrature IC modulates a VCO on the output frequency.
2. An intermidiate frequency VCO in the range 50-250MHz is modulated and then upconverted to output frequency.
Number 1 is obviously much simpler (less filtering) - that is why I suspect it to have some serious drawbacks!
Is there a short answer to why these two approaches both are used?
Jan