es: PRACTICAL IP AND TELECOM FOR BROADCAST ENGINEERING AND OPERATIONS An established Field Engineering and Customer Support organ- ization Manufactured and sold the same or similar equipment for at least 10 years Will commit to making replacement parts available from a US or North American Free Trade Area depot for at least 10 years after shipment of any equipment ordered in connection with this specification Currently offers telephone and Internet parts ordering and knowledge base support 24 X 7 Established practice in regularly scheduled training seminars for station personnel Transmitter General Requirements Highly parallel architecture is preferred. Examples of such architec- ture are 1 for 1 backup of major components including exciter-modu- lator, intermediate power amplifier (IPA), high power amplifier (HPA), and all power supplies. Each of these components must be available to substitute for its counterpart upon failure of the unit in service. Ideally, substitution of the backup on failure would be via a monitoring point detecting a failure such as loss of DC operating voltage, output signal, high VSWR, or other similar mechanism. Such activity would also trigger alarms available for remote sensing through transmitter status and control interface. Designs employing high power combining networks to combine the output of high power amplifiers may be an acceptable alternative in specific cases where it's deemed to be cost effective. Figure 7-1 is a functional block diagram showing all major elements of the DTV Transmitter System. Functional Description An acceptable transmitter system will generate FCC ATSC Output using ATSC standard input signals and commercial grade power. The transmitter must be capable of being controlled and monitored via status and remote control interface as depicted in Figure 7-3. 7 SPECIFYING EQUIPMENT AND SERVICES AC Power Regulator AC Power Regulator Power Supply A Power Supply B SMPTE 310 Exciter - Motorized Modulator Amplifier Switch Ref CLK Reject Load SMPTE 310 Exciter - RF Lo