BCM43455 Preliminary Data Sheet
RDS/RBDS
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High Cut—A programmable high-cut filter is provided to reduce the amount of high-frequency noise
caused by static in the output audio signal. Like the soft mute circuit, it is fully programmable to allow for
any amount of high cut based on the FM signal C/N.
Audio Pause Detect—The FM receiver monitors the magnitude of the audio signal and notifies the host
through an interrupt when the magnitude of the signal has fallen below the threshold set for a
programmable period. This feature can be used to provide alternate frequency jumps during periods of
silence to minimize disturbances to the listener. Filtering techniques are used within the audio pause
detection block to provide more robust presence-to-silence detection and silence-to-presence detection.
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Automatic Antenna Tuning—The BCM43455 has an on-chip automatic antenna tuning network. When
used with a single off-chip inductor, the on-chip circuitry automatically chooses an optimal on-chip matching
component to obtain the highest signal strength for the desired frequency. The high-Q nature of this
matching network simultaneously provides out-of-band blocking protection as well as a reduction of
radiated spurious emissions from the FM antenna. It is designed to accommodate a wide range of external
wire antennas.
RDS/RBDS
The BCM43455 integrates a RDS/RBDS modem and codec, the decoder includes programmable filtering and
buffering functions, and the encoder includes the option to encode messages to PS or RT frame format with
programmable scrolling in PS mode. The RDS/RBDS data can be read out in receive mode or delivered in
transmit mode through either the HCI interface.
In addition, the RDS/RBDS functionality supports the following:
Receive
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Block decoding, error correction and synchronization
Flywheel synchronization feature, allowing the host to set parameters for acquisition, maintenance, and
loss of sync. (It is possible to set up the BCM43455 such that synchronization is achieved when a minimum
of two good blocks (error free) are decoded in sequence. The number of good blocks required for sync is
programmable.)
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Storage capability up to 126 blocks of RDS data
Full or partial block B match detect and interrupt to host
Audio pause detection with programmable parameters
Program identification (PI) code detection and interrupt to host
Automatic frequency jump
Block E filtering
Soft mute
Signal dependent mono/stereo blend
Programmable pre-emphasis
Broadcom®
November 5, 2015 • 43455-DS109-R
Page 64
BROADCOM CONFIDENTIAL
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