The following block diagram is a block diagram of the SMPTE UHD-SDI receiver.
Data from the serial transceiver RX enters the SMPTE UHD-SDI receiver on the rx_data_in port 20-bit per clock cycle for SD, HD, and 3G
modes or 40-bit per clock cycle for 6G and 12G modes. In SD mode, the 20-bit of data on
rx_data_in go to the data recovery unit (DRU) which
recovers 10 bit data words from the 11X oversampled data.
The data is descrambled by the SDI descrambler and then word aligned by
the SDI framer. Immediately following the framer is the sync bit restore function. This
function restores the 3FF and 000 values that are modified by the transmitter to reduce
run lengths in 6G and 12G-SDI modes. These three blocks run at the full rx_clk speed and process 40, 20, or 10 bit of data per
clock cycle depending on the SDI mode.
The output of the SDI framer goes to the stream demux which determines how many streams are interleaved together and then separates each data stream on a separate data path. There can be one, two, four, eight, or sixteen active data streams on the output of the stream demultiplexer.
Each data stream pair (and Y and C pair) go to a stream processing unit which does CRC error checking, line number capture, and ST 352 packet capture. In the diagram, the details of the stream processing unit are shown for stream processor 0 which processes data stream 1 and data stream 2. Data stream 1 also goes to the EDH processor for error detection in SD-SDI mode. Not shown in the block diagram is that data stream 2 can also be directed to stream processing unit 1 so that, in 3G-SDI level A mode, the ST 352 packet on data stream 2 can be captured. In 3G-SDI level A mode, both the Y (data stream 1) and C (data stream 2) data streams contain ST 352 packets. In addition to the 3G-SDI level A, 12G-SDI and 6G-SDI allow ST 352 packets to be sent and received on both Y and C data streams.
The stream demux also extracts the video timing and produces the rx_eav, rx_sav, and
rx_trs timing signals. These timing signals are
used by the SDI mode detection and transport detection blocks.