Subelement H: Modulation— Topic 58: SSB Modulation
Question 3-58H1
Element 3 (GROL)In Figure 3H17, the block labeled 4 would indicate that this schematic is most likely a/an:
Explanation
Block 4 in Figure 3H17 represents a **balanced modulator**. A balanced modulator is a crucial component in the generation of a Single Sideband (SSB) signal. Its primary function is to combine an audio signal with an RF carrier, but it effectively **suppresses the carrier frequency**, producing only the upper and lower sidebands. This carrier suppression is a defining characteristic of SSB transmission. Following this stage, a filter would typically select one of the sidebands. Therefore, the presence of a balanced modulator strongly indicates that the schematic is for an SSB radio transmitter.
Audio amplifiers simply amplify audio signals, RADAR systems use pulsed RF signals for detection, and Wireless LANs use complex digital modulation for data, none of which primarily employ a balanced modulator for carrier suppression in this manner.
Related Questions
3-57H5 What is meant by the term modulation index?3-57H6 In an FM-phone signal, what is the term for the maximum deviation from the carrier frequency divided by the maximum audio modulating frequency?3-58H2 In Figure 3H17, which block diagram symbol (labeled 1 through 4) represents where audio intelligence is inserted?3-58H3 What kind of input signal could be used to test the amplitude linearity of a single-sideband phone transmitter while viewing the output on an oscilloscope?3-58H4 What does a two-tone test illustrate on an oscilloscope?