Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!accuvax.nwu.edu!nucsrl!telecom-request From: Andrew Peed Newsgroups: comp.dcom.telecom Subject: Re: IRIDIUM: Motorola's New Cellular Phone System Message-ID: <10663@accuvax.nwu.edu> Date: 9 Aug 90 14:02:54 GMT Sender: news@accuvax.nwu.edu Reply-To: motcid!peed@uunet.uu.net Organization: Motorola Inc., Cellular Infrastructure Div., Arlington Hgts, IL Lines: 49 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 10, Issue 555, Message 7 of 9 cfogg@milton.u.washington.edu (Chad Fogg) writes: >In article <10448@accuvax.nwu.edu> you write: >>Voice: >> The system is designed as an entirely digital communications >>system with 8KHz bandwidth available for each voice channel. Vocoders >Is this 8KHz sample rate or 8KHz frequency bandwidth? The former >would imply a data rate equal to ISDN's B channel (8bits*8KHz= 64000 >bits/sec). If I understand audio sampling correctly, the frequecy >range is roughly equal to half the sample rate. I assume this is an 8KHz frequency bandwith. Unfortunately, I can't do more than assume; the one thing I forgot to do when I sent this press release to Patrick was include a disclaimer. I'm an employee of the Cellular Infrastructure Division of Motorola, but I understand that the Iridium project is being handled jointly by the Government Electronics Group and a new Satellite Communications business unit. Personally, I know just about as much about Iridium as you do, based on information in the press release. >>operating at 4.8 kilobits per second are employed in the user units to >>recreate the audio signals and in the gateways to couple to the analog >>PSTNs. >>Data: >> The system is designed to allow a user to substitute a data >>link in lieu of a voice link which would operate at a rate of 2400 >>baud. >2400 bps is kind of a dissapointment when the voice channel is >operating at 64,000 bps. Agreed. Although, I feel inclined to point out that this IS cellular; to my knowledge, cellular is being primarily used for voice, since cellular transmission quality is not usually (in my experience, anyway) clean enough for practical data transmission. Besides, the LAST thing we need is some goombah trying to fax a document to Glocka Morra with one hand while steering his car with the other, with a newspaper propped up on his steering wheel, coffee on the dashboard, and Walkman in his ears... Andrew B. Peed Motorola, Inc. ...!uunet!motcid!peed Cellular Infrastructure Division (708) 632-5271 1501 W.Shure Dr., Arlington Heights, IL, 60074