The RF-ADC can be configured to operate in multi-band mode. This is where the incoming analog input consists of baseband signals up-converted (mixed) to different carrier frequencies. Multiple DDC blocks are used to down-convert the analog input to recover the separate baseband signals.
The RF-ADC multi-band feature supports the following configurations:
- Real Dual-Band
2x multi-band real data per pair. One RF-ADC analog input is active. Both RF-ADC digital DDC channels are enabled.
- I/Q Dual-Band
2x multi-band I/Q data per pair. Both RF-ADC inputs are active, one for I and one for Q. Both RF-ADC digital DDC channels are enabled.
- Real Quad-Band (Quad ADC tile only)
4x multi-band real data per tile. One RF-ADC analog input is active. All four RF-ADC digital DDC channels are enabled.
- I/Q Quad-Band (Quad ADC tile only)
4x multi-band I/Q data per tile. Two RF-ADC inputs are active, one for I and one for Q. All four RF-ADC digital DDC channels are enabled.
When multi-band is off the I and Q inputs pass straight through the multi-band routing logic. When multi-band is on the I and Q inputs are routed to multiple DDC blocks in the tile.
RF-ADC multi-band is implemented by routing the output of one RF-ADC analog block to multiple RF-ADC DDC blocks. Each block handles one band of data, and can mix from multiple carriers to baseband. This is shown for a Quad ADC tile in the following figure.
Here, RF-ADC Tile 0 (Tile_224) is configured in real input to I/Q output mode. ADC0 converts the dual-band signal; ADC1 is off. The top pair can be configured as independent RF-ADCs. The dual-band output is routed to the DDC blocks of ADC0 and ADC1. The mixers in the DDC blocks can be configured to extract the correct band from the incoming data. RF-ADC Tile 1 (Tile_225) is configured in 4x multi-band I/Q input to I/Q output mode. Here ADC0 carries the quad-band I signal and ADC1 carries the Q data. ADC2 and ADC3 are off. The outputs of the RF-ADCs are routed to all four DDC blocks. Each DDC can be configured to extract the data from the desired frequency band.