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Article #895Re: HD RADIO is no worse than DAB or DRM radio
From: SFTV_troy
Date: Sun, 30 Sep 2007 08:16
Date: Sun, 30 Sep 2007 08:16
23 lines
2930 bytes
2930 bytes
Earl Kiosterud wrote: > > Synchronous AM demodulation uses a locally regenerated carrier, fed along with the AM signal > (upper or lower set of sidebands) to a multiplier (modulator). The result is the audio. It > replaces the envelope (diode) detector usually used. You can think of it as another superhet > stage where the result, instead of another IF frequency, is the baseband audio. That's > because the local oscillator is the same frequency as the carrier of the (IF) signal, so the > difference is zero. The sidebands wind up translated to baseband audio instead of to > another IF frequency. > > There are advantages. Since one set of sidebands or the other can be used, if there's a > distant station 10KHz away, causing that AM whistle, you just switch to the other set of > sidebands, whichever comes in the cleanest. Also, it doesn't depend on proper amplitude and > phase of both sets of sidebands to work properly, as does the regular envelope detector, so > it works better with impaired signals. I only understood about 75% of what your wrote, but if I understand your meaning, this new receiving technique would not improve the sound (it would still be limited from 100-6000 hertz), but would only reduce interference.
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X-Google-Thread: fb1f8,428391383e1324a5 X-Google-Thread: 10a749,428391383e1324a5 X-Google-Thread: 114aac,cd4ad6cadcf2b245 X-Google-Thread: f7d8a,cd4ad6cadcf2b245 X-Google-Attributes: gidfb1f8,gid10a749,gid114aac,gidf7d8a,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: arc1-ca.pugleaf.net!g2news2.google.com!postnews.google.com!y42g2000hsy.googlegroups.com!not-for-mail From: SFTV_troy <SFTV_troy@yahoo.com> Newsgroups: rec.audio.tech,rec.audio.car,rec.radio.shortwave,ba.broadcast Subject: Re: HD RADIO is no worse than DAB or DRM radio Date: Sun, 30 Sep 2007 01:16:12 -0700 Organization: http://groups.google.com Lines: 24 Message-ID: <1191140172.205755.136880@y42g2000hsy.googlegroups.com> References: <1191065666.205537.159420@n39g2000hsh.googlegroups.com> <1191096585.135753.167530@d55g2000hsg.googlegroups.com> <46ffb388.44729093@news.plus.net> <1191099764.677637.18050@22g2000hsm.googlegroups.com> <1191108136.459409.212620@50g2000hsm.googlegroups.com> <%vBLi.275$0I5.137@trnddc08> NNTP-Posting-Host: 24.249.100.9 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" X-Trace: posting.google.com 1191140172 31980 127.0.0.1 (30 Sep 2007 08:16:12 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Sun, 30 Sep 2007 08:16:12 +0000 (UTC) In-Reply-To: <%vBLi.275$0I5.137@trnddc08> User-Agent: G2/1.0 X-HTTP-UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.7) Gecko/20070914 Firefox/2.0.0.7,gzip(gfe),gzip(gfe) Complaints-To: groups-abuse@google.com Injection-Info: y42g2000hsy.googlegroups.com; posting-host=24.249.100.9; posting-account=ps2QrAMAAAA6_jCuRt2JEIpn5Otqf_w0