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USER’S MANUAL FOR CZH618F-1000/500C TRANSMITTER
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8. System Control Logic
8.1 RF Output Control
The RF output of CZH618F-1000/500C digital FM broadcast transmitter is controlled by
switches: RF Switch in main menu and period control switch in RTC menu.
RF Switch:
When RF Switch is off, turn off RF power.
When RF Switch is on and Period Control is disabled, turn RF power on to setting power.
When RF Switch is on and Period Control is enabled, RF power is controlled by Period
Control function (see Period Control).
Period Control:
When RF Switch is on and Period Control is enabled, the control method is as follow:
The system reads current time through RTC and check whether current time is falling into any
of the three periods. If yes; turn on RF power to its setting power. Else turn off RF power. A period
is invalid if start time is greater than or equal to end time. Current time will never fall into an
invalid period. If three periods are all invalid, turn RF power off for ever.
8.2 Remote Control
Remote control is set in <SET> menu. When remote control is enabled, remote LED on front
panel is lit and parameters are controlled by remote host and can not be changed locally except
“Remote” flag in <SET> menu. Updated parameters will be automatically stored in EEPROM.
When remote is disabled, remote host can not control over the exciter but locally does.
Updated parameters will be automatically stored in EEPROM.
RS232 or RS485 are used for remote control. Before enabling remote control, baud rate and
device address should be properly set.
8.3 Change RF Frequency
After RF frequency changed, RF power will drop to 0 first, and then increase to its setting
power.
