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Old 13-11-2017, 21:00   #51
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Originally Posted by zfyoung
This is the only short term stopgap solutions to the HF broadcast problem.
Actually the main complaint I have against DRM is that the codec (AAC+/xHE) remains proprietary product. This not only put a hurdle on wider adoption of modern broadcast standard, it also discourage any attempt to improve or it co-opted to better systems. And indeed there is a far better solution to this kludge: why let the broadcaster to dictate the configuration of transmission signals (64/16QAM, bitrate, AAC/xHE etc.) at TX side, why NOT let the receiver to decide that at RX side depending on the local SNR level? This strategy incorporate the agility of analogue system and efficiency of digital system and DX friendly.

If you're implying that the DRM standard has asymmetric ability, then I was unaware of that capability. As Laurent suggested, dynamic capability certainly would be better than any static configuration, but asymmetric capability is another matter entirely. Explain to me how your scenario would work with the DRM standard both technically and experientially. Keep it simple and, if appropriate, use the DR-111 as the receiver in any example.

Are you suggesting that if a broadcaster used a 64 QAM configuration, then the DRM standard allows for the asymmetic reconfiguration at the receiver to 16 QAM?

Personally, I support the concept of dynamic configuration at the RX, but I think it's best to place the onus on the broadcaster for the foreseeable future. Yes, the BBC still broadcasts automatic frequency changes when no such frequencies exist and most digital broadcasters can't even broadcast time signals correctly, etc...

P.S. I'm pretty sure that Laurent and yourself are thinking in terms of TX initiated reconfigurations while I'm thinking in terms of RX initiated reconfigurations (adaptions since the RX can't talk to TX) .... For example, I'm outside the target area of a broadcaster, but I want my receiver to decode the digital broadcast if possible. Hence, I need it to switch to a mode where decoding is possible ... IF possible.

Last edited by tpreitzel : 14-11-2017 at 00:43.
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