A single modulator (SSBM) accepts and RF input and a modulation (IF) input and produces either the upper (RF+IF) or lower (RF-IF) sideband. The original RF input (carrier) and the unwanted sideband are suppressed at the output. This is accompolished by using the phase cancellation method single sideband modulation. The SSBM is constructed with two IF input ports. By changing the modulating signal from IF1 to IF2 either the upper or lower RF sideband can be selected. Sideband selection can, therefore, be done by IF switching between IF1 and IF2. The user must provide a quadrature IF drive, either by using an external 90° hybrid covering the IF frequency of interest or by generating two equal amplitude signals differing in phase by 90°. This quadrature drive can be obtained digitally or by differential phase shift networks. Approximately +10 dBm, or ±15 mA, drive is required. The other Model type (Models having -30, -60-60 etc., suffixes) make use of internal IF hybrids covering the octave IF bandwidth listed. Units are tested only at one IF Frequency (band center), but will meet specifications over the entire IF octave. A single IF input of +10 dBm to + 13 dBm is required. For most SSBM applications the RF input signal is 0 dBm or less and the high level (+10 dBm) switching input. These harmonics can be reduced at the expense of carrier suppression by having the RF input signal as the high level (+10 dBm) input.