1. Home
  2. Electronics Design
  3. Low Frequency Radio Transmission for long distance.
  4. Page 6

Low Frequency Radio Transmission for long distance.

I really wonder if patent US20130121397 A1 would hold up. It seems to fail the "obviousness" test....

"
  1. A radio receiver method, said method comprising: receiving a broadcast signal comprising phase modulation (PM) over a legacy amplitude modulated (AM) signal, said broadcast signal encoded with time information; and extracting said time information from the phase of said received signal. "

Clearly, this is describing the concept of receiving the signal that is being broadcast without indicating anything unique about how to do that. Claims starting with 9 reiterate the same claims but in regard to an actual receiver, again, without saying anything specific about said receiver. Claim 18 is very similar to claim 1.

So what in patent US20130121397 A1 is actually "novel"?

--

Rick
Reply to
rickman
Loading thread data ...

The European synchronization source is probably German DCF77, on

77.5 kHz, near Frankfurt am Main. Its range is around 2000 km, so here at the limit, the clocks sync in nighttime, but not so well during sunlit hours. 
--

-TV 
Helsinki, Finland
Reply to
Tauno Voipio

actually, once it is despread, the GPS signal is well ABOVE the thermal noise floor

it only "seems" to be near the noise floor due to the spreading

Reply to
makolber

If you had a 'perfect" spectrum analyzer, you wouldn't see it. It is

*below* the noise floor.
Reply to
krw

Nope. The GPS L1 signal is about 24MHz wide: and arrives on earth about at about 26dB below the thermal noise floor. In order to see anything that's 24MHz wide, you'll need to run your spectrum analyzer with a rather wide IF bandwidth, which will bring in plenty of noise under which the signal can hide. You won't see anything unless your perfect spectrum analyzer can run near absolute zero temperature, where the thermal noise is gone.

When you de-spread the spread spectrum signal, and enjoy the benefits of processing gain, the signal becomes rather narrow band (about

100Hz) and increases in amplitude thanks to a theoretical 43.1dB of processing gain. Starting at 26dB below the noise, the signal is now: -26dB + 43.1dB = 17.1dB above the noise which can easily be seen on a spectrum analyzer. 
--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558
Reply to
Jeff Liebermann

On Wed, 20 Apr 2016 21:13:56 -0400, krw Gave us:

You're an idiot.

0dBm = 0W or negative infinity

-192.5 dBm is the thermal noise floor for 1Hz bandwidth in outer space..

-127.5 is the typical received signal strength from a GSP satellite

-111 dBm is the thermal noise floor for COMMERCIAL GPS single channel signal bandwidth (2MHz)

Nice try, punk.

Reply to
DecadentLinuxUserNumeroUno

0dBm means 0dB above a reference level of 1 milliwatt into 50 ohms.

What's a GSP satellite? If you mean GPS, the typical signal power is about -130dBm.

That's correct for L1. Either way, the signal is: 111 - 130 = 19dB below the noise floor.

Drivel: Home made GPS. Looks nice:

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558
Reply to
Jeff Liebermann

I think not.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com
Reply to
John Larkin

On Mon, 02 May 2016 12:12:34 -0700, Jeff Liebermann Gave us:

It was supposed to be negative infinity dBm but that "character" is not available.

Reply to
DecadentLinuxUserNumeroUno

On Mon, 02 May 2016 12:12:34 -0700, Jeff Liebermann Gave us:

Pissing and moaning about some mild dyslexia? f*ck you "computah" retahd.

Reply to
DecadentLinuxUserNumeroUno

On Mon, 02 May 2016 12:25:48 -0700, John Larkin Gave us:

It is supposed to be an infinity sign, idiot.

Reply to
DecadentLinuxUserNumeroUno

0 dBm is not 0 watts.

0 dBm is not negative infinity.

What did you mean?

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com
Reply to
John Larkin

You're always wrong, AlwaysWrong.

LOL! You're funny!

You're *ALWAYS* wrong. You add to the proof every day. If you had an ounce of gray matter you'd learn how to use Google.

Reply to
krw

He means that he's wrong. ...about everything.

Reply to
krw

But when he is wrong, WE are stupid!

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com
Reply to
John Larkin

That sort of mistake is not going to look good in a proposal. He should check his work before publishing.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com
Reply to
John Larkin

...and he's wrong. What would you expect?

Reply to
krw

On Mon, 02 May 2016 16:17:12 -0700, John Larkin Gave us:

I told you it was supposed to be an infinity symbol

meter range.

Reply to
DecadentLinuxUserNumeroUno

Nobody uses infinity when measuring power levels. Negative infinity makes no sense and you're still wrong.

A while ago, I couldn't convince you to say something nice. Perhaps I can get you to admit that you were wrong. Just admit that you screwed up, and we can continue from there. No flame war required. It only hurts for a moment and will do little to damage what is left of your reputation. I know, because my batting average in SED is only slightly better than yours.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558
Reply to
Jeff Liebermann

On Mon, 02 May 2016 18:15:59 -0700, Jeff Liebermann Gave us:

Negative infinity represents zero power, which is not well expressed in dBm, putz.. So the "value" IS "negative infinity"

Reply to
DecadentLinuxUserNumeroUno

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.