For the same average transmitted or modulated signal power and the same average noise power in the message bandwidth, a coherent SSB receiver will have exactly the same output signal-to-noise ratio as

Key Points

• DSB and SSB have the same noise performance as the baseband comm system.​
• The figure of merit of a DSB-SC receiver or that of an SSB receiver using coherent detection is always unity.

Additional Information 

• The corresponding figure of merit of an AM receiver using envelope detection is always less than unity.
  •  In other words, the noise performance of an AM receiver is always inferior to that a DSB-SC receiver.
  • This is due to the wastage of transmitter power, which results from transmitting the carrier as a component of AM wave.