Advantages of Base Modulation over Collector Modulation in Transistor Class C Amplifier

Base modulation and collector modulation are two methods of modulating a transistor class C amplifier. Both methods have their advantages and disadvantages. However, base modulation has some advantages over collector modulation, as discussed below:

Lower Modulating Power Required
• With base modulation, lower modulating power is required compared to collector modulation.
• In base modulation, the modulating signal is applied to the base of the transistor, which modulates the base current, and hence the collector current. This results in a lower power requirement for the modulating signal.
• In collector modulation, the modulating signal is applied to the collector of the transistor, which modulates the collector current. This requires a higher power level for the modulating signal.

Higher Power Output per Transistor
• With base modulation, higher power output per transistor can be achieved compared to collector modulation.
• In base modulation, the transistor operates in class C, which means that it conducts only during a portion of the input signal cycle. This results in a high collector efficiency and a high power output per transistor.
• In collector modulation, the transistor operates in class B, which means that it conducts during half of the input signal cycle. This results in a lower efficiency and a lower power output per transistor.

Better Efficiency
• Base modulation provides better efficiency compared to collector modulation.
• In base modulation, the transistor operates in class C, which results in a higher collector efficiency and a better power transfer efficiency.
• In collector modulation, the transistor operates in class B, which results in a lower collector efficiency and a lower power transfer efficiency.

Better Transmission
• Base modulation provides better transmission compared to collector modulation.
• In base modulation, the modulating signal is applied directly to the base of the transistor, which results in better linearity and a better signal-to-noise ratio.
• In collector modulation, the modulating signal is applied to the collector of the transistor, which results in a lower linearity and a lower signal-to-noise ratio.

Conclusion
In conclusion, base modulation has some advantages over collector modulation in transistor class C amplifiers. It requires lower modulating power, provides higher power output per transistor, better efficiency, and better transmission.