Wednesday
Apr072010
TWiRT 27 - FSK and Loose Ends
Wednesday, April 7, 2010 at 11:54PM What are FSK, BPSK, and QPSK? Plus mic processing and an AES white paper.
Kirk Harnack - Executive Director, Int'l Business Development, Telos-Omnia-Axia
Tom Ray - VP, Engineering, Buckley Broadcasting, WOR, New York, W2TRR
Chris Tobin - CBS Radio, New York
Some web sites mentioned in this episode:
Phase Shift Keying, including BPSK and QPSK
EBU Evaluations of Multi-Channel Audio Codecs (pdf)
Audio Noise Reduction Techniques - Meenakshi Singhvi (pp 42-46)
Download the show here...
Reader Comments (3)
Is the RSS feed broken?
My google reader can see the item but never download the file. Now, I cannot d/l this file: twirt 27 either.
Thanks for the heads-up! There was a typo in the RSS feed (my fault). Fixed now.
If you subscribe using iTunes, you'll want to unsubscribe and resubscribe. Just do this from your iTunes "Podcasts" directory. No need to visit the iTunes Store to do this.
Best,
Kirk
Hi Guys,
I've just downloaded and read the EBU paper. This one refers to surround (not stereo) which is why the bitrates are higher than I'd have expected (200-312kbps for emission).
It's important to differentiate between production, distribution, and emission applications when establishing bitrates. (BTW the report on Phase 3 of these tests has just been released - http://tech.ebu.ch/webdav/site/tech/shared/tech/tech3339.pdf)
The most recent EBU tech report I've seen on stereo bitrates is from 2003 - before AAC so it is out of date. http://tech.ebu.ch/publications/tech3296
I recall that there is info out there that suggests a sweet spot for AACplus of 48 to 96kbps for emission, but I can't find it right now.
Also am I to infer from this that there are no objective tests to quantify codec performance? If not is any work being done on this?
These Mushra tests are very complex and expensive, so there's probably few organizations able to do this stuff.
Cheers,
Peter S.