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On Sat, 01 Oct 2005 01:43:09 GMT, Korbin Dallas
said in rec.radio.scanner: On Fri, 30 Sep 2005 11:29:31 -0400, Al Klein wrote: On Fri, 30 Sep 2005 13:35:23 GMT, "Jim Hackett" said in rec.radio.scanner: Digital? Most of what we call "digital" is NFM or SNFM. Actually "Digital" is C4FM. And the modulation on the carrier is??? AM? PM?? FM?? What bandwidth is it? There's a difference between the process of putting information on the carrier and the format that information comes in. The OP was asking about the physical layer, as specified by "AM/FM ..." etc.. |
#2
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On Fri, 30 Sep 2005 23:45:46 -0400, Al Klein wrote:
On Sat, 01 Oct 2005 01:43:09 GMT, Korbin Dallas said in rec.radio.scanner: On Fri, 30 Sep 2005 11:29:31 -0400, Al Klein wrote: On Fri, 30 Sep 2005 13:35:23 GMT, "Jim Hackett" said in rec.radio.scanner: Digital? Most of what we call "digital" is NFM or SNFM. Actually "Digital" is C4FM. And the modulation on the carrier is??? AM? PM?? FM?? What bandwidth is it? There's a difference between the process of putting information on the carrier and the format that information comes in. The OP was asking about the physical layer, as specified by "AM/FM ..." etc.. The standard is APCO 25, which defines BW to be 6Khz and Modulation as C4FM. For more details see: http://www.apcointl.org/frequency/project25/ -- Korbin Dallas The name was changed to protect the guilty. |
#3
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On Sat, 01 Oct 2005 19:48:00 GMT, Korbin Dallas
said in rec.radio.scanner: On Fri, 30 Sep 2005 23:45:46 -0400, Al Klein wrote: On Sat, 01 Oct 2005 01:43:09 GMT, Korbin Dallas said in rec.radio.scanner: On Fri, 30 Sep 2005 11:29:31 -0400, Al Klein wrote: On Fri, 30 Sep 2005 13:35:23 GMT, "Jim Hackett" said in rec.radio.scanner: Digital? Most of what we call "digital" is NFM or SNFM. Actually "Digital" is C4FM. And the modulation on the carrier is??? AM? PM?? FM?? What bandwidth is it? There's a difference between the process of putting information on the carrier and the format that information comes in. The OP was asking about the physical layer, as specified by "AM/FM ..." etc.. The standard is APCO 25, which defines BW to be 6Khz and Modulation as C4FM. Again - what's the physical layer? Id the frequency of the carrier changed? The amplitude? The phase? Some other characteristic of it? The OP wasn't asking about the logical layer (which is where C4FM sits), he was asking about the physical layer. |
#4
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On Sat, 01 Oct 2005 17:49:28 -0400, Al Klein wrote:
On Sat, 01 Oct 2005 19:48:00 GMT, Korbin Dallas said in rec.radio.scanner: On Fri, 30 Sep 2005 23:45:46 -0400, Al Klein wrote: On Sat, 01 Oct 2005 01:43:09 GMT, Korbin Dallas said in rec.radio.scanner: On Fri, 30 Sep 2005 11:29:31 -0400, Al Klein wrote: On Fri, 30 Sep 2005 13:35:23 GMT, "Jim Hackett" said in rec.radio.scanner: Digital? Most of what we call "digital" is NFM or SNFM. Actually "Digital" is C4FM. And the modulation on the carrier is??? AM? PM?? FM?? What bandwidth is it? There's a difference between the process of putting information on the carrier and the format that information comes in. The OP was asking about the physical layer, as specified by "AM/FM ..." etc.. The standard is APCO 25, which defines BW to be 6Khz and Modulation as C4FM. Again - what's the physical layer? Id the frequency of the carrier changed? The amplitude? The phase? Some other characteristic of it? The OP wasn't asking about the logical layer (which is where C4FM sits), he was asking about the physical layer. Gee I don't know, Since it has FM in the NAME maybe its FM. Or perhaps you prefer the Emission designator of 8K10F1E. I always thought Modulation and Channel access methods are typically placed at layer 1. -- Korbin Dallas The name was changed to protect the guilty. |
#5
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On Mon, 03 Oct 2005 23:28:37 GMT, Korbin Dallas
said in rec.radio.scanner: On Sat, 01 Oct 2005 17:49:28 -0400, Al Klein wrote: Again - what's the physical layer? Id the frequency of the carrier changed? The amplitude? The phase? Some other characteristic of it? The OP wasn't asking about the logical layer (which is where C4FM sits), he was asking about the physical layer. Gee I don't know, Since it has FM in the NAME maybe its FM. Or perhaps you prefer the Emission designator of 8K10F1E. Point, head, whoosh. I always thought Modulation and Channel access methods are typically placed at layer 1. Modulation is layer 1. "Channel access"? Wazzat? PL? |
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