*Question E7E11:
Which type of detector is used for demodulating SSB signals?*  

*Correct Answer is  C: Product detector*  

### AI Response: (may contain errors)  

To demodulate SSB (Single Sideband) signals, a **product detector** is used. Here's why:

1. **Why the correct answer is correct:**
   - A product detector is specifically designed to demodulate SSB and CW (Continuous Wave) signals. It works by mixing the incoming SSB signal with a locally generated carrier signal. This process effectively shifts the signal back to the audio frequency range, allowing you to hear the transmitted audio.

2. **Why the other choices are incorrect:**
   - **A: Discriminator**  
     - A discriminator is used for demodulating FM (Frequency Modulation) signals, not SSB. It works by converting frequency variations in the FM signal into amplitude variations.
   - **B: Phase detector**  
     - A phase detector is typically used in phase-locked loops (PLLs) and is not suitable for demodulating SSB signals. It compares the phase of two input signals and outputs a voltage proportional to their phase difference.
   - **D: Phase comparator**  
     - Similar to a phase detector, a phase comparator is used in PLLs and other applications where phase comparison is needed. It is not used for SSB demodulation.

3. **Useful formulas or rules of thumb:**
   - The product detector uses the principle of mixing, where the output is the product of the input signal and the local oscillator signal. This can be represented as:
     $$ V_{\text{out}} = V_{\text{in}} \times V_{\text{LO}} $$
   - The mixing process results in sum and difference frequencies, and the desired audio signal is extracted by filtering out the unwanted components.

Understanding the role of a product detector in SSB demodulation is crucial for effectively receiving and processing these types of signals.