GC5318 Datasheet, PDF (5/45 Pages) Texas Instruments – HIGH-DENSITY DIGITAL UPCONVERTER

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GC5318
HIGH-DENSITY DIGITAL UPCONVERTER
SLWS187 – JULY 2006
The outputs of all DUCs drive four independent complex sum chains. Any DUC can contribute (or not) to
any or all of the four sum chains. The output of a DUC block sum chain drives the sum chain input of the
next block. The first DUC to output data is DUC0, while the last is DUC11. The two or four outputs of a
DUC are the sum of all the contributing channels of all the higher numbered DUC blocks and itself. The
sum chain inputs of DUC 11 are grounded. Within the chain, all DUC blocks from 0 up to the highest
numbered DUC in use must be turned on; otherwise, the sum chain is broken.
The transmit output interface takes the four summed chains of DUC output data from the output of DUC 0,
then scales and rounds them to a user-programmed number of bits. Composite power meters with
programmable integration periods and intervals compute the power in each of the four output streams.
The data is then formatted for output over the four tx_data_out ports.
2.1 Digital Upconvert Block (DUC)
4 Sign on Top
16 Data
15 Zeros on Bottom
Serial
I, Q
Serial
Interface
Gain
Pilot
Insertion
(UMTS Only)
16
16
34
36
5 Guard on Top
18 Data
13 on Bottom
18
Round
RMS
Power Meter
Frequency ³²
Phase ¹⁶
NCO
Programmable 18
FIR Filter
Interp by 2
Compensating 18
FIR Filter
Interp by 2
Six Stage
18
CIC Filter
Interp 4-32
18
Delay Adjust
CDMA A & B Channels, or 1 UMTS Channel
Sum1
Input
From Previous Transmit Channel
Sum2
Input
Sum3
Input
Sum4
Input
Sum1
Output
Sum2
Output
Sum3
Output
Sum4
Output
To Next Transmit Channel
Figure 2-2. Digital Upconvert Block
GC5318 Operation
5