| 摘要 |
<p>The present invention relates to a QPSK nodulator for modulating two different input bit streams with a subharmonic pump carrier signal to produce an appropriately encoded QPSK output sig- al. The subharmonic pump carrier signal used is a submultiple of a predetermined microwave or millimeter-wave carrier frequency. The QPSK modulator is capable of being fabricated on a planar substrate 24 using appropriate stripline filters 12,13,16,17,20,21 and a mixer diode 18,19 in each of an in-phase 11 and quadrature 11 signal path. A fin line arrangement, also capable of fabrication on the substrate, can be used to introduce an appro- oriately phased subharmonic pump carrier signal into each of the in-phase and quadrature signal oaths before each mixer diode. Each mixer diode mixes the associated data bit stream and one of the two appropriately phased pump carrier signals to produce separate output signals which modulate along separate orthogonal axes, which output signals are combined in combiner 22 to produce the QPSK modulator output signal.</p> |
