Carrier suppression in a single-sideband transmitter takes place in:

In an SSB transmitter, the specific circuit responsible for eliminating the continuous carrier wave is the balanced modulator. It takes the modulating audio and the RF carrier as inputs, mixing them in a way that produces the sum and difference frequencies (the upper and lower sidebands) while structurally nulling out the original carrier frequency. Although filters are used later in the transmission chain, their primary purpose is to remove the unwanted sideband, not the carrier. The carrier has already been effectively suppressed by the time the signal reaches the mechanical or crystal filter.