erlock status All system overloads Power supply voltages and currents System block diagrams to aid in fault location AC line voltages Phase loss status A summary of active and inactive fault conditions shall be stored and available for view on the transmitter GUI. Circuitry shall be provided to lower the transmitter power output in the case of increased VSWR. Decreasing VSWR shall cause the power level to increase until the original output power is restored. All logic control memory shall be backed up SO as to return the transmitter to its mode of operation immediately preceding an AC power failure of any duration. RF Combiner When multiple RF amplifiers are used to meet specific transmitter power output or multiple transmitters operating on different carrier frequencies are fed to a single ended passive transmission system, an 7 SPECIFYING EQUIPMENT AND SERVICES RF Combining until will be employed. In such cases, the RF combiner and all transmitter units shall perform as a system. The system will be required to meet all FCC requirements as though it were operating as individual components. The RF combiner shall not degrade the spec- tral performance of any single transmitter. The combiner will include an RF sample point at each input and output of the combiner. The combiner must be capable of continuous operation across the temperature and humidity range as the transmitter with all inputs from all transmitters operating at 110% of their TPO. RF insertion loss shall not exceed 0.4 dB from input terminals to output terminal with all inputs operating at transmitter TPO levels. Channel isolation shall be greater than 35 dB between any input and any other inputs Group delay shall be within + 20 nanoseconds across the channel pass band. Transmitter System Performance Each transmitter shall meet or exceed specifications in this section while operating across a range of 25-110% of TPO after installation in accordance with the manufacturers instructions. TABLE 7-1 Sideband performance Comply with FCC radiation mask in ef