Thread: Modern Day FMs
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Old 2007-09-05, 04:47 PM
procella procella is offline
 
Join Date: Sep 2006
Re: Modern Day FMs

Quote:
Originally Posted by Five
well let me dig up some of my FM-sourced shows when I get home and get back to you on that... iirc the older FM broadcasts have a more hazy cutoff, but the new ones look like they've been very abruptly sawed off. In the case of these two broadcasts I couldn't find blocks and they sound decent, so maybe they're not lossy, perhaps they are using a more accurate digital LPF I'm not 100% certain, either. However there are other recent FM captures that I am certain about and I can post some SA screencaps from those, as well as some older FM shows from the pre-mp3 days and we can compare.
Thought I try to google a little:

May 4 2005, 16:37 Post #51

The BBC distribute FM around the country in NICAM format, so assuming you can receive a relatively strong FM signal then you're basically hearing NICAM-encoded audio.

NICAM is 14-bit PCM companded to 10-bits using a sampling frequency of 32 kHz (see http://tallyho.bc.nu/~steve/nicam.html). So, not capable of CD-quality, but not too far off it. And although it might appear that its audio bandwidth will be narrower than MPEG audio because of the lower sampling frequency, all digital radio stations in the UK that I'm aware of lowpass filter with a cutoff frequency of about 15.5 KHz anyway, so there's really no difference in that respect.


Not sure if you know about that. 2 years old but NICAM should be a good guess still.
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