SI4770-77-A20 Datasheet, PDF (42/54 Pages) Silicon Laboratories – HIGH-PERFORMANCE CONSUMER ELECTRONICS

Si4770/77-A20
4.17. AM Hi-Cut Control
AM hi-cut control is employed on AM audio outputs with
degradation of signal quality. Signal metrics such as
SNR or on-channel RSSI activate the hi-cut filter.
Programmable minimum and maximum thresholds are
available for all metrics. Attack and release rates for hi-
cut are programmable for all metrics.
The level of hi-cut applied can be monitored with the
received signal quality command. Hi-cut can be
disabled by setting the hi-cut filter setting to the default
audio bandwidth for AM. Further information is provided
in the Programming Guide.
4.18. FM Hi-Cut Control
FM hi-cut control applies a low-pass filter on the (L+R)
audio upon degradation of received signal quality.
Signal metrics, such as USN, on-channel RSSI, and
multipath interference, activate the hi-cut filter.
Programmable minimum and maximum thresholds are
available for all metrics. Attack and release rates are
also programmable for all metrics. The level of hi-cut
applied can be monitored with the received signal
quality command. Further information is provided in the
Programming Guide.
4.19. FM Hi-Blend
FM hi-blend control applies a low-pass filter on the (L-R)
audio upon degradation of received signal quality.
Signal metrics, such as USN, on-channel RSSI, and
multipath interference, activate the hi-blend filter.
Programmable minimum and maximum thresholds are
available for all metrics. Attack and release rates for are
also programmable for all metrics. The level of hi-blend
applied can be monitored with the received signal
quality command. Further information is provided in the
Programming Guide.
4.20. AM Lo-Cut
AM lo-cut is employed on audio outputs for rejection of
power-supply 50/60 Hz interference. AM lo-cut is a high
pass filter. Lo-cut is enabled by default and can be
disabled by programming the filter to being switched off.
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Rev. 0.9