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#1
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Sidebands
"Well, it's like this. The story starts in 1915, when mankind discovered
sidebands. Now possessing this superior understanding of the AM signal, radio scientists began to understand the implications of their discovery. Soon afterwards, our old friends at Bell Labs, who have discovered practically everything, developed a method for removing one of the sidebands of an AM signal but retaining all the essential modulation components. As an expert of that day supposedly said, "both sidebands are saying the same thing" (Goodman, 1948). " From: http://www.hamradiomarket.com/articles/SSBHistory.htm I was born after 1915. I am supposing that in that time was possibility to tune to the three different frequences. Am I right? S* |
#2
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Sidebands
Szczepan Bialek wrote:
"Well, it's like this. The story starts in 1915, when mankind discovered sidebands. Now possessing this superior understanding of the AM signal, radio scientists began to understand the implications of their discovery. Soon afterwards, our old friends at Bell Labs, who have discovered practically everything, developed a method for removing one of the sidebands of an AM signal but retaining all the essential modulation components. As an expert of that day supposedly said, "both sidebands are saying the same thing" (Goodman, 1948). " From: http://www.hamradiomarket.com/articles/SSBHistory.htm I was born after 1915. I am supposing that in that time was possibility to tune to the three different frequences. Am I right? S* Nope, you are just spouting word salad gibberish as usual. See: http://en.wikipedia.org/wiki/Single-sideband_modulation http://en.wikipedia.org/wiki/Bandwid...nal_processing) http://en.wikipedia.org/wiki/Passband -- Jim Pennino Remove .spam.sux to reply. |
#3
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Sidebands
Użytkownik napisał w wiadomo¶ci ... Szczepan Bialek wrote: "Well, it's like this. The story starts in 1915, when mankind discovered sidebands. Now possessing this superior understanding of the AM signal, radio scientists began to understand the implications of their discovery. Soon afterwards, our old friends at Bell Labs, who have discovered practically everything, developed a method for removing one of the sidebands of an AM signal but retaining all the essential modulation components. As an expert of that day supposedly said, "both sidebands are saying the same thing" (Goodman, 1948). " From: http://www.hamradiomarket.com/articles/SSBHistory.htm I was born after 1915. I am supposing that in that time was possibility to tune to the three different frequences. Am I right? S* Nope, you are just spouting word salad gibberish as usual. See: http://en.wikipedia.org/wiki/Single-sideband_modulation http://en.wikipedia.org/wiki/Bandwid...nal_processing) http://en.wikipedia.org/wiki/Passband Here are thy unrestricted signal (upper diagram). It has the three peaks: http://en.wikipedia.org/wiki/File:Pa...schematic3.png So in an old radio the same station was in the three places (on the scale) close to one another. Am I right? S* |
#4
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Sidebands
Szczepan Bialek wrote:
Here are thy unrestricted signal (upper diagram). It has the three peaks: http://en.wikipedia.org/wiki/File:Pa...schematic3.png So in an old radio the same station was in the three places (on the scale) close to one another. Am I right? S* Nope, you haven't the slightest bit of understanding of what the term "passband" means so your question is nonsense. -- Jim Pennino Remove .spam.sux to reply. |
#5
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Sidebands
On Dec 21, 9:13*am, "Szczepan Bialek" wrote:
"Well, it's like this. The story starts in 1915, when mankind discovered sidebands. Now possessing this superior understanding of the AM signal, radio scientists began to understand the implications of their discovery. Soon afterwards, our old friends at Bell Labs, who have discovered practically everything, developed a method for removing one of the sidebands of an AM signal but retaining all the essential modulation components. As an expert of that day supposedly said, "both sidebands are saying the same thing" (Goodman, 1948). " From:http://www.hamradiomarket.com/articles/SSBHistory.htm I was born after 1915. I am supposing that in that time was possibility to tune to the three different frequences. Am I right? S* Only three? If the modulation is a complex signal (not just a single sinusoid), you'll get (ideally) a carrier on a single frequency, and upper and lower sidebands spanning a range of frequencies. Any decent spectrum analyzer will easily resolve these components. Communications receivers with narrow bandwidth, sharp cutoff filters can also resolve them, of course. And only "in that time"? You still can: there are plenty of AM stations broadcasting in the 0.5MHz to 30MHz range (and some outside that). But in 1915, it may well have been easier to analyze the signal mathematically than with hardware. The hardware may not have been very common, but certainly the math identities required were readily available, as was Fourier analysis. What if both sidebands are NOT "saying the same thing"? Then, for instance, you can broadcast stereo in a way that receivers mixing the two sidebands will still receive an acceptable mono signal. Cheers, Tom |
#6
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Sidebands
On Dec 21, 6:14*pm, "Szczepan Bialek" wrote:
U ytkownik napisa w wiadomo ... Szczepan Bialek wrote: "Well, it's like this. The story starts in 1915, when mankind discovered sidebands. Now possessing this superior understanding of the AM signal, radio scientists began to understand the implications of their discovery. Soon afterwards, our old friends at Bell Labs, who have discovered practically everything, developed a method for removing one of the sidebands of an AM signal but retaining all the essential modulation components. As an expert of that day supposedly said, "both sidebands are saying the same thing" (Goodman, 1948). " From: http://www.hamradiomarket.com/articles/SSBHistory.htm I was born after 1915. I am supposing that in that time was possibility to tune to the three different frequences. Am I right? S* Nope, you are just spouting word salad gibberish as usual. See: http://en.wikipedia.org/wiki/Single-sideband_modulation http://en.wikipedia.org/wiki/Bandwid...nal_processing) http://en.wikipedia.org/wiki/Passband Here are thy unrestricted signal (upper diagram). It has the three peaks:http://en.wikipedia.org/wiki/File:Pa...schematic3.png So in an old radio the same station was in the three places (on the scale) close to one another. Am I right? S* no |
#8
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Sidebands
Uzytkownik "K1TTT" napisal w wiadomosci ... On Dec 21, 6:14 pm, "Szczepan Bialek" wrote: Szczepan Bialek wrote: "Well, it's like this. The story starts in 1915, when mankind discovered sidebands. Now possessing this superior understanding of the AM signal, radio scientists began to understand the implications of their discovery. Soon afterwards, our old friends at Bell Labs, who have discovered practically everything, developed a method for removing one of the sidebands of an AM signal but retaining all the essential modulation components. As an expert of that day supposedly said, "both sidebands are saying the same thing" (Goodman, 1948). " From: http://www.hamradiomarket.com/articles/SSBHistory.htm I was born after 1915. I am supposing that in that time was possibility to tune to the three different frequences. Am I right? Here are the unrestricted signal (upper diagram). It has the three peaks: http://en.wikipedia.org/wiki/File:Pa...schematic3.png So in an old radio the same station was in the three places (on the scale) close to one another. Am I right? no Now my radio use FM. The one station is on the distance circle 1cm. In 1915 was the same for AM? S* |
#9
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Sidebands
"K7ITM" wrote ... On Dec 21, 9:13 am, "Szczepan Bialek" wrote: "Well, it's like this. The story starts in 1915, when mankind discovered sidebands. Now possessing this superior understanding of the AM signal, radio scientists began to understand the implications of their discovery. Soon afterwards, our old friends at Bell Labs, who have discovered practically everything, developed a method for removing one of the sidebands of an AM signal but retaining all the essential modulation components. As an expert of that day supposedly said, "both sidebands are saying the same thing" (Goodman, 1948). " From:http://www.hamradiomarket.com/articles/SSBHistory.htm I was born after 1915. I am supposing that in that time was possibility to tune to the three different frequences. Am I right? S* Only three? If the modulation is a complex signal (not just a single sinusoid), you'll get (ideally) a carrier on a single frequency, and upper and lower sidebands spanning a range of frequencies. Any decent spectrum analyzer will easily resolve these components. What was in 1915? Communications receivers with narrow bandwidth, sharp cutoff filters can also resolve them, of course. Have such Author of SSBHistory in 1915? And only "in that time"? You still can: there are plenty of AM stations broadcasting in the 0.5MHz to 30MHz range (and some outside that). But in 1915, it may well have been easier to analyze the signal mathematically than with hardware. The hardware may not have been very common, but certainly the math identities required were readily available, as was Fourier analysis. What if both sidebands are NOT "saying the same thing"? Then, for instance, you can broadcast stereo in a way that receivers mixing the two sidebands will still receive an acceptable mono signal. I am trying to find if that SSB from 1915 were the distance dependent. S* |
#10
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Sidebands
On
What if both sidebands are NOT "saying the same thing"? Then, for instance, you can broadcast stereo in a way that receivers mixing the two sidebands will still receive an acceptable mono signal. I am trying to find if that SSB from 1915 were the distance dependent. S* Distance from where? You are not making sense. Jeff |
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