Sorry, its not clear for me. Modulated signal could be expressed as sum of signals with different frequencies, but will it be registered by receiver as signal

Sorry, its not clear for me. Modulated signal could be expressed as sum of signals with different frequencies, but will it be registered by receiver as signal at these frequencies? Suppose we send 1hz signal with length = 1 hour. In the middle we change amplitude of one wave to 1/2. Does recievers recieves mix of different frequencies?