The following block diagram shows a block diagram of the SMPTE UHD-SDI
transmitter. Up to sixteen SDI data streams (tx_ds1_in
through tx_ds16_in) enter the transmitter and first go
through the ST 352 insertion modules where ST 352 payload ID packets are optionally
inserted. The data streams output from the ST 352 insertion modules are called tx_ds1_st352_out through tx_ds16_st352_out. These streams are output so that the customer
application can insert ancillary data after ST 352 packets are inserted. The remaining
portion of the transmitter can either use the streams output by the ST 352 packet
insertion modules directly or the sixteen tx_ds1_anc_in through tx_ds16_anc_in
data streams from the customer application ancillary data insertion function. Note that
if the tx_dsn_anc_in data streams are used, they must
be full SDI data streams, not just ancillary data.
Most frequently, ST 352 packets are only inserted into the Y data stream of each Y/C data stream pair. However, in 3G-SDI level A mode-only, ST 352 packets must be inserted into both data stream 1 and data stream 2. Muxes in the SMPTE UHD-SDI transmitter allow data stream 2 to be routed through the second ST 352 insertion module in 3G-SDI level A mode to allow that module to insert ST 352 packets into data stream 2, whereas normally data stream 3 is handled by the second ST 352 insertion module. The SMPTE UHD-SDI core has the capability to insert ST 352 packets into the C data stream and can be controlled using a parameter.
Each Y/C pair of data streams then goes through a stream processing block
which optionally does line number insertion and CRC generation and insertion. Following
stream processing, the data streams are interleaved by the stream MUX. This results in a
multiplexed SDI data stream that is 40, 20, or 10 bit wide depending on the SDI mode.
For 6G-SDI and 12G-SDI, the sync bit insertion algorithm is performed to reduce run
lengths. Then the multiplexed data stream is scrambled by the SDI scrambler. In SD-SDI
mode, the 10-bit scrambled data stream is processed by the SD-SDI bit replication module
to replicate each bit 11 times to create a 270 Mb/s SDI serial stream with the serial
transceiver TX running at 2.97 Gb/s. Finally, the data is output on the tx_txdata port to the serial transceiver to be
serialized.