RFBA & RFBA Plus User Manual
Crown Broadcast
Page 8
Mixed Combination of Other Configurations
The RFBA is capable of performing many of the above configurations concurrently. Tuner #1 is always
able to receive a broadcast station and output audio. It is also always able to reconstruct an FM
composite signal from the station received. If the modulation
monitor
option is installed, it can also do
a full analysis of the signal received on Tuner #1.
System Overview
The RF Broadcast Appliance (RFBA) has been designed to perform multiple functions. The RFBA includes
three independent automotive-grade DSP-based receivers. Each receiver is capable of receiving AM,
FM, NOAA Weather band or Public Service frequencies. This makes the RFBA desirable for meeting the
broadcasters EAS needs of monitoring of multiple stations. The RFBA also incorporates a DSP based FM
composite generator that can be used for FM translators. The FM composite generator has additional
functionality to add RDS capability to your translated signal, acting in a RDS pass thru mode or a user
programmable mode. The RFBA can also be used as a triple tuner modulation
monitor
and RDS
decoder. Band and frequency selection is performed by front panel user control or remote Ethernet
control.
Functionality
The onboard AM/FM receiver utilizes a Digital Signal Processor (DSP) that incorporates advanced
algorithms to provide world-class receiver performance. Tuner parameters have been optimized by
experts in AM/FM reception to provide the best overall performance for this specific product,
eliminating the need for broadcasters to make adjustments. The receiver is capable of tuning:
1) FM frequencies from 76.00 – 108.00 MHz in steps of 0.05 MHz (50 kHz)
2) AM frequencies from 520 – 1710 kHz in 10 kHz increments
3) AM frequencies from 531 – 1629 kHz in 9 kHz increments
4) All NOAA weather band channels from 162.400 – 162.550 MHz (Channels 1 – 7)
5) Public Service band from 144.000 – 175.000 MHz in 5 kHz increments
Block Diagram
A high level block diagram of the RFBA is shown in
. As described previously, this product
contains three independent tuners. Each tuner is capable of receiving AM, FM, NOAA Weather band or
Public Service band. Each tuner has its own BNC RF connector. The right and left audio signals for each
tuner are available as differential outputs on the supplied Phoenix connector. The audio outputs of
tuner #1 are also used by the onboard DSP to generate a FM composite signal that can be used for
translators. The onboard DSP also uses an RDS encoder so the user can add RDS information to the
translator output. The FM composite output is available via a BNC connector on the rear of the product.
Tuner #3 has an option to have a differential or single-ended audio output for the right and left
channels. In the single-ended mode the negative outputs are used as connections to an internal relay.
The relay can be programmed via the display or Ethernet to open or close based on certain events, such
