CATV 64-QAM Transmitter

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drmpeg
Posts: 62
Joined: Fri Mar 01, 2013 3:58 am
Location: Silicon Valley
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CATV 64-QAM Transmitter

Post by drmpeg » Thu Mar 20, 2014 2:05 pm

Clayton (argilo) VE3IRR has added another digital television transmission format to the bladeRF repertoire. It's an implementation of the 64-QAM portion of the North American cable TV standard ANSI/SCTE 07 2013 (also known as ITU-T J.83 Annex B).

https://github.com/argilo/gr-qam

Here's a constellation plot (at 429 MHz) from a demodulator evaluation board (at about 34 dB demodulator signal to noise ratio).

Image

A stand-alone Python script for bladeRF is available here.

https://github.com/drmpeg/dtv-utils/blo ... m-blade.py

A 26.970352 Mbps test clip is available here.

http://www.w6rz.net/advqam64.ts

Ron

drmpeg
Posts: 62
Joined: Fri Mar 01, 2013 3:58 am
Location: Silicon Valley
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Re: CATV 64-QAM Transmitter

Post by drmpeg » Thu Mar 20, 2014 2:10 pm

Here's a spectrum analyzer trace of the bladeRF sending two 64-QAM channels simultaneously (on cable channels 58 and 59) with the qam64_double.grc GRC flowgraph.

Image

Ron

unwiredben
Posts: 3
Joined: Tue May 27, 2014 3:33 pm

Re: CATV 64-QAM Transmitter

Post by unwiredben » Fri Oct 24, 2014 2:05 pm

Just wanted to report that I successfully built this and used it with GNU Radio 3.7.5 to modulate a 64-QAM bitrate TS file that I had. Great job, and looking forward to 256-QAM if that's possible in the future.

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