| 摘要 |
PURPOSE:To save power and to decrease the temperature rise, by supplying DC bias for transistors used through the use of AC voltage of required carrier for modulator operation. CONSTITUTION:The active operation bias to NPN transistors (TR) 1 and 2 used for switching elements is fed by the carrier in phase via a transformer T3. Further, the base emitter potential VBE and collector emitter potential VCE are given with the AC voltage of carrier of VBE=VPXn and VCE=VPXm (where; VP is the carrier input voltage). As the operation of the transformer, the winding ratio (m), (n) of the transformer T3 is decided so that VCE>VBE is obtained and required bias voltage for the active operation of transistors is obtained. Accordingly, TRs 1 and 2 operate as the switching elements of on/off with the period of carrier, allowing required active type modulation operation. |
