GC5325SEK Datasheet, PDF (5/24 Pages) Texas Instruments – GC5325 Wideband Digital Predistortion Transmit Processor

GC5325
www.ti.com .............................................................................................................................................................................................. SLWS215 – JANUARY 2009
• The output of the Farrow resampler; this is also called the reference signal.
• The feedback output; this represents the waveform as seen by the PA.
• The error output
• Testbus(15:0)
The reference and feedback buffers are time-aligned by the GC5325, because there may be a delay of tens or
even hundreds of samples between the transmitted signal and the feedback signal from the PA output. The
capture controller can trigger a capture on several different metrics, including an above-threshold peak count or
an average signal power value.
Input and Output Syncs
The GC5325 features multiple-user programmable input syncs. These are typically used as trigger mechanisms
to activate features within the device. These triggers can be provided internally or through externally provided
inputs. The input syncs can be used to trigger:
• Power measurements
• Initializing/loading the feedback, equalizer, LUTs, etc.
• Flush out data within the processing blocks of the device
• Feedback path tuner alignment
• Capturing and sourcing of data through SCBs
Programmable Power Meters
There are three power meter locations/functions within the GC5325. The first is a channel RMS power meter.
The second power meter is located at the output of the CFR block, and the final power detector is similar to the
CFR output power detector and is located at the Farrow resampler output. This power meter can measure RMS
power integrated up to a million samples at the DPD sample rate.
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