Ham Radio General Class Practice Test

What is the primary purpose of using a balanced modulator in an SSB transmission?

1. To increase the audio fidelity

2. To filter out unwanted harmonics

3. To produce only upper and lower sidebands without the carrier

4. To simplify the modulation process

The correct answer is: To produce only upper and lower sidebands without the carrier

The primary purpose of using a balanced modulator in an SSB (Single Sideband) transmission is to produce only the upper and lower sidebands without transmitting the carrier signal. In SSB communications, it is essential to maximize the efficiency of radio frequency transmission, and one effective way to achieve this is by removing the carrier frequency, which can consume power without conveying additional information. A balanced modulator accomplishes this by combining the audio input signal with the carrier wave in such a way that the carrier is canceled out, leaving only the sidebands. This results in the transmission of the audio information found in the modulated frequency without the energy waste associated with broadcasting a continuous carrier wave. By removing the carrier, SSB transmission allows for more efficient use of bandwidth and improves the signal-to-noise ratio, leading to clearer communications at lower power levels. Other purposes, such as increasing audio fidelity or filtering out unwanted harmonics, do not directly pertain to the function of a balanced modulator in the context of SSB operation. Simplifying the modulation process may occur as a consequence of using SSB, but it is not the primary goal of employing a balanced modulator.