GC5318 Datasheet, PDF (24/45 Pages) Texas Instruments – HIGH-DENSITY DIGITAL UPCONVERTER

GC5318
HIGH-DENSITY DIGITAL UPCONVERTER
SLWS187 – JULY 2006
Table 2-18. Programming
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VARIABLE
DESCRIPTION
comp_pmeterX_result_lsb(15:0)
Lower 16 bits of the composite power measurement for sum chain X. X = 0, 1, 2, or 3
comp_pmeterX_result_msb(31:16) Upper 16 bits of the composite power measurement for sum chain X. X = 0, 1, 2, or 3
comp_pmeterX_integration_lsb(15:0) Lower 16 bits of the 21-bit integration period. X = 0, 1, 2, or 3
comp_pmeterX_integration_msb(20:16) Upper five bits of the 21-bit integration period. X = 0, 1, 2, or 3
comp_pmeterX_sync_delay(8:0)
Power meter delay sync period. X = 0, 1, 2, or 3
comp_pmeterX_interval_lsb(15:0) Lower 16 bits of the 21-bit measurement interval. X = 0, 1, 2, or 3
comp_pmeterX_interval_msb(20:16) Upper five bits of the 21-bit measurement interval. The Interval time must be greater than the
integration time for each of the four composite power meters. X = 0, 1, 2, or 3
ssel_comp_pmeter_X(2:0)
Sync source. X = 0, 1, 2, or 3
2.3 GC5318 Output Interface
I
18
Sum Chain 0
18
Q
18
txout_a
I
Sum Chain 1
Q
txout_b
I
Sum Chain 2
Q
txout_c
I
Sum Chain 3
Q
txout_d
Format
2
txclk_out
tx_i_flag
Figure 2-19. Output Interface
The GC5318 provides four output signal data ports, as shown in Figure 2-19. Each port can be enabled or
disabled. Disabled ports are held low and can also be tri-stated.
Each 18-bit port outputs the sum of the carriers contributing to the composite signal stack. Output data
can be real or complex valued. Complex I/Q data can be output either interleaved over a single output port
or over two ports separately.
Real output data would generally be selected driving a single D/A converter to an IF frequency. Complex
output data would be selected when subsequent post-processing such as power amplifier predistortion is
employed. Complex outputs can also be used to drive a pair of D/A converters (one for I, the other for Q)
for direct I/Q upconversion using a quadrature modulator device.
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GC5318 Operation