|
SECTION 3: DESCRIPTION AND STATION BLOCK DIAGRAM
Nucleus Advanced Control Board (NAC) and Control Front Panel
The microprocessor based Nucleus Advanced Control Board (NAC) accepts input from the paging controller {Ad¬vanced Simulcast Controller(s) (ASC)} and in turn controls the rest of the Nucleus station. Control path input from the ASC comes through either Line 1 audio wireline, an optional RF link receiver, or digital data via satellite. You can program or verify parameters and functions using the Nucleus Front Panel, which includes a 15-pushbutton keypad and LED display.
To prevent the transmit signal from “splattering” into adjacent transmit channels, a splatter filter implemented in the DSP eliminates higher frequency modulation components. The particular splatter filter (140 or 250 us) can be chosen using the Control Front Panel to match other paging stations being simulcast with the Nucleus Paging Station.
The reference modulation signal, which is used to modulate the exciter reference frequency, is also sent from the DSP circuitry to the Audio Interface Circuitry, and then output to the Exciter Module as the REF MOD signal.
The Host Microprocessor controls the operation of the station as determined by the station software and parameters. You can program or verify control parameters using the Control Front Panel, which includes a 15-pushbutton keypad and LED display.
The Serial Peripheral Interface (SPI) bus is used as a general-purpose communications bus to allow the Host Microproces¬sor to communicate with other modules in the station, via the Host ASIC. This allows alarm information to be displayed on the Control Front Panel.
|
