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On Jul 15, 2:14 pm, Jeff Liebermann wrote:
Radium hath wroth: how would u like to change the cell phone industry? Analog cells phones should stop using FM and should start using AM with SHF frequencies - at least 3 GHz and at most 30 GHz. http://en.wikipedia.org/wiki/Super_high_frequency There will probably need to be 8-10 times more cell sites built than are currently in use on 800/900 and 1800/1900MHz. Why? Equally important, SHF frequencies can efficiently transmit signals using extremely small transmitters. Longer wavelengths require larger transmitters. They do? I didn't know that. My 49MHz automobile alarm dongle isn't much larger than my 2400MHz USB wi-fi dongle. Are you sure the transmitter has to be bigger or were you thinking of the antenna? Maybe the antenna. I choose AM because it requires less bandwidth than FM. In addition, AM tends to retain reception of rather weak signals, while FM "considers" such signals to be absent. I'll make it really simple for you. FM is "hi-fi", while AM is noisy "no-fi". FM has too much hiss. FM signals are lost very easily. AM tends to retain reception of a signals even when this signal is extremely weak. In FM, once you go below a certain wattage, you completely lose the signal, and the annoying hiss begins. With AM it is much easier to receive the low-power signal. AM maybe more vulnerable to electronic disturbances but so what? The magnetic RF interferences that are heard on the AM radio are entertaining compared to the deafening hiss on the FM radio. For decent quality, you gotta have FM. Nope. For decent quality sound you need audio that is uncompressed PCM [similar to CDs and WAVE files] with a sample rate of at least 44.1 KHz and a bit-resolution of at least 16-bit. Or the analog equivalent. |
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