4. THE Orban PRO CHANNEL GENERATOR The Professional Channel Generator (8182A/PRO or 8185A/PRO) augments the OPTIMOD Television Stereo Generator (8182A/SG or 8185A) by adding a voice or data communications channel to the composite baseband output of the Stereo Generator. The Pro Channel input signal is amplified, processed, then used to modulate a subcarrier generated in sync with the main carrier. The 8182A/PRO and 8185A/PRO are identical, and are installed identically in the Orban 8182A/SG and 8185A TV Stereo Generators. Throughout this manual, any reference to the “8182A/PRO” applies to the 8185A/PRO as well. Physically, 8182A/PRO consists of two additional plug-in circuit cards (#9 and #10) for the Stereo Generator, retrofit shielding for the 8182A/SG’s Card #8, and a new control subpanel. Card #9 circuitry processes the inpul signal, and the subcarrier is generated on Card #10. The 8182A/PRO conforms to specifications set by the Broadcast Television Systems Committee (BTSC) of the Electronic Industries Association (EIA).