STA662 STMicroelectronics, STA662 Datasheet - Page 5

• Manufacturer Part Number: STA662
• Description: Audio Transmitters, Receivers, Transceivers AM/FM, DAB/DAB+/DMB-A, DRM Multi-Standard Digital Radio Receiver
• Manufacturer: STMicroelectronics

STA662
Figure 2.
1.2
Figure 2
demodulating and decoding.
DRM demodulating and decoding functional data flow diagram
FM signal processing
STA662 features several strategies to improve the reception of FM signals. A DSP controlled
variable bandwidth filtering of the complex base-band allows to greatly cope with adjacent
channel interferences. Multipath fading distortion is mitigated by exploiting antenna
switching (the antenna RF-switch is controlled through Digital pins).
After dynamic filtering, the IFP block demodulates the complex base-band signal; the result
of the detection is the composite MPX signal, which carries the stereo-encoded audio and
the Radio Data System (RDS) information.
The MPX signal is still affected by the instantaneous spike noise originated by the
electromagnetic fields due to fast current variations, and to the high current discharges in
the ignition phase of the car engine. Dedicated algorithms for spike detection and
suppression have been developed; this processing is supported by a set of dedicated
hardware accellerators under the control and supervision of the ARM946 microcontroller.
Audio information is subsequently retrieved from the processed MPX by the mixed
hardware/software stereo-decoder, which also performs typical weak-signal processing
functions as stereo channel blending, audio soft-muting for low antenna signals, and de-
emphasis filtering. After further sample rate reduction, the audio is available for transmission
to external devices.
presents a functional diagram describing the data flow inside STA662 for DRM
Doc ID 023407 Rev 1
Description
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