Figure 1 shows the block diagram of the ATSC transmission system. The M/H system receives two types of input streams: one for the main service input consisting of the normal ATSC transport stream (TS) packets and the other for the M/H service input.
The process procedure on M/H services can be divided into two stages: Pre-processor (highlighted in light yellow) and Post-processor (highlighted in light purple).
Pre-processor rearranges the M/H service data into an M/H structure, enhances the robustness of the M/H service data through FEC encoding, inserts training sequences, and then encapsulate the data into MHE transport stream packets.
Post-processor processes the main service data by legacy ATSC 8-VSB encoding and manipulated the pre-processed M/H service data in the combined stream to ensure full compatibility with ATSC 8-VSB receivers.
Figure 1. ATSC-M/H transmission system
ATSC-M/H transmission system can have two sets of streams as input: one for the MPEG TS packets of the main service data, and the other for the M/H service data. Keysight N7623Cenables you to input the payload for main service data and M/H service data separately or input the multiplexed file which includes both the main service data and the M/H service data.
In the figure 1, point A and point B refer to two input points supported in the N7623C.
Point A corresponds to Main & M/H Service payload type. The input main service payload and the M/H service payload should be set in the software separately.
Point B corresponds to Multiplexed TS payload type. The input payload should be the service data after packet multiplexer at point B, including both the M/H service data and main service data.
Figure 2. Payload types in N7623C.