GC5328 Datasheet, PDF (9/27 Pages) Texas Instruments – GC5328 Low-Power Wideband Digital Predistortion Transmit Processor

GC5328
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SLWS218A – OCTOBER 2009 – REVISED OCTOBER 2009
There are special DSP software PA protection modes that use the capture buffer to
determine the DPD correction applied to the signal, the error between the DPD
reference input and the feedback signal. The capture buffers are also used in the
initial bulk delay and fractional delay alignment.
INPUT SYNCS AND OUTPUT SYNC
The GC5328 features multiple user-programmable input syncs. There are three syncs sampled with the BBClock,
(A, B, and C), and the Sync D,DC as an LVDS sync sampled by the DPD clock. Internally, the GC5328 can also
generate timed and software-controlled syncs. The sync A input is required for the GC5328 hardware to initialize.
It should ideally be the start of the frame or frame downlink. The output sync is a test signal used for debugging.
The input syncs can be used to trigger:
• Power measurements
• DUC channel delay, dither, and mixer-phase alignment
• Initializing/loading the DUC, feedback, equalizer, LUTs, etc.
• Feedback path tuner alignment
• Capturing and sourcing of data through SCBs
NOTE
The sync A external synchronization should match the customer Tx frame (total Tx
period – i.e., 5 ms).
See the baseband interface figure, these synchronization signals must meet the
timing of the BBClk.
POWER METERS AND PEAK I–or–Q MONITORS
There are three integrated I² + Q² power meters in the GC5328:
• GPP – each baseband input channel
• CFR – the CFR input or output, and which antenna stream (0, 1)
• DPD – the input to the DPD nonlinear correction after the DPDL gain, and which antenna stream (0, 1)
There are several peak I or Q monitors within the GC5328.
• FRW– The resampled combined IQ interleaved input to the DPD
• DPD – The input to the DPD nonlinear correction after the DPDL gain
• DPD – After the nonlinear correction in DPD, and separately after the linear correction in DPD
• FDBK – There is a peak monitor at the output of the feedback path.
NOTE
The DSP host software has a HW POWER meter setup and Get(Monitor) function to
configure and get data from the integrated I²+Q² values.
Copyright © 2009, Texas Instruments Incorporated
Product Folder Link(s): GC5328
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