Question:
For signal transmission, modulation is necessary
For signal transmission, modulation is necessary
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Higher frequency ⇒ efficient radiation.
Updated On: May 1, 2026
- reduce distortion
- change frequency
- hide signal
- long distance transmission
- easy amplification
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The Correct Option is D
Solution and Explanation
Concept: Need for modulation
A baseband (low-frequency) signal cannot be transmitted efficiently over long distances due to practical limitations.
Step 1: Antenna size issue
For efficient radiation: \[ \text{Antenna length} \approx \frac{\lambda}{4} \] Low-frequency signals have very large wavelength $\lambda$, hence require impractically large antennas.
Step 2: Poor radiation efficiency
Low-frequency signals do not radiate energy effectively, leading to weak transmission.
Step 3: Role of modulation
Modulation shifts the signal to a high-frequency carrier: \[ f_c \gg f_m \] This reduces wavelength and allows efficient transmission. Conclusion:
\[ \boxed{\text{Modulation is required to transmit signals over long distances}} \] \hr
A baseband (low-frequency) signal cannot be transmitted efficiently over long distances due to practical limitations.
Step 1: Antenna size issue
For efficient radiation: \[ \text{Antenna length} \approx \frac{\lambda}{4} \] Low-frequency signals have very large wavelength $\lambda$, hence require impractically large antennas.
Step 2: Poor radiation efficiency
Low-frequency signals do not radiate energy effectively, leading to weak transmission.
Step 3: Role of modulation
Modulation shifts the signal to a high-frequency carrier: \[ f_c \gg f_m \] This reduces wavelength and allows efficient transmission. Conclusion:
\[ \boxed{\text{Modulation is required to transmit signals over long distances}} \] \hr
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