work on docs

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Andreas Eversberg 2017-10-03 10:48:50 +02:00
parent 91b48c09de
commit 7cbebaeb75
12 changed files with 95 additions and 7 deletions

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@ -521,7 +521,7 @@ But you get a busy signal, that means there is no channel.
</p>
<p>
Now run your base station on channel 1.
Now run your base station on channel 1. (With SDR use channel 17.)
You may add '-G x' or '--gfs x' command line option to change the station ID from default to any value you like. (see help)
If you have a phone that supports GFS 19, please use this GFS 19 to reduce the transmit power of the phone to 100 mW instead of 15 Watts.
To see if your phone supports it, try to preselect GFS 19.

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@ -22,7 +22,7 @@ History
</p>
<p>
C-Netz was the third mobile telephone network in Germany.
C-Netz (aka C450 or C-Tel) was the third mobile telephone network in Germany.
It existed between 1984 (officially Mai 1985) and December 2000.
In 1989, the German Wall came down and C-Netz was quickly deployed in eastern Germany to support the congested telephone network.
It was the first cellular system in Germany, so frequencies could be used more efficiently, as it had been done in the USA with AMPS.

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@ -27,8 +27,7 @@ NMT was a Scandinavian cellular network, developed by and used in Scandinavian c
If was used in the Baltic countries, Switzerland, Netherlands, Hungary, Poland, Bulgaria, Romania, Czech Republic, Slovakia, Slovenia, Serbia, Turkey, Croatia, Bosnia, Russia, Ukraine and in Asia.
The NMT network was opened in Sweden and Norway in 1981, and in Denmark and Finland in 1982. Iceland joined in 1986.
Networks where shut down in 2000 (Estonia), 2002 (Finland), 2004 (Norway), 2007 (Sweden), 2010 (Iceland).
In 1989, the German Wall came down and C-Netz was quickly deployed in eastern Germany to support the congested fixed network.
It was a cellular system, so frequencies could be used efficiently..
It was a cellular system, so frequencies could be used efficiently.
It offered handover capability, so moving phones could change cells during a call.
Authentication was introduces (SIS), to prevent fraud, but it was optional.
Older phones without SIS could be cloned by receiving and decoding the roaming update message.

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@ -23,6 +23,38 @@
History
</p>
<p>
Radiocom 2000 (sometimes R2000) was a cellular network used in France.
The network was developed by France Telekom and Matra and became the third mobile network.
There are many similarities to the NMT network, but it was a complete own design.
Development started in 1981 and the network was launched in Paris in 1985, it gradually replaced the second network "correspondance publique".
It was a cellular system, so frequencies could be used efficiently.
The system was capable of allocating channels dynamically.
Handover was implemented later and called RHD "R&eacute;seau Haute Densit&eacute;" (network with high desity).
It was possible to run private base station, where own mobiles were allowed to call only.
In 1988, it had 60,000 subscribers and more than 90% of devices are installed in vehicles.
Originally the 200 MHz and 400 MHz bands were used.
Due to congesting in 1990, the 900 MHz band was introduced.
The network was closed for the exclusive benefit of the standard GSM in July 28th 2000.
</p>
<p>
<ul>
<li>Frequency range UHF: 424.800 - 427.9875 MHz (down-link); 414.800 - 417.9875 MHz (up-link)
<li>256 voice or contol channels
<li>Duplex distance: 10 MHz
<li>Channel spacing: 12.5 KHz
<li>Voice modulation: FM
<li>Signaling modulation: carrier FSK
<li>Frequency deviation: 1500 Hz ??? (Voice); 1425 Hz (FSK)
<li>Mobile station transmit power: 1 or 6..10 Watts
<li>Features: Speech Compandor (BS-&gt;MS only), Group calls
</ul>
</p>
<p>
</p>
<p class="toppic">
<a name="howitworks"></a>
How it works

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@ -107,8 +107,8 @@ You will get an ASCII art plot of received IQ data.
Press 'q' again and you will get a logarithmic view of IQ vectors.
Press 'q' again to turn off this view.
Please monitor this view when the phone tries to call or register.
If the dots are yellow or red, the received signal overdrives the ADC.
If the linear view shows not a nice, skinny circle, if the phone transmits, the input of your SDR might be saturated.
If the dots are yellow, or red, the received signal may overdrive the ADC.
Especially when the linear view shows a deformed circle (or even rectangle), reduce RX level.
</p>
<center><img src="display-spectrum.png"/></center>
@ -116,7 +116,7 @@ If the linear view shows not a nice, skinny circle, if the phone transmits, the
<p>
Press 's' to get an ASCII art graph of received frequency spectrum.
The spectrum's bandwidth is defined by the sample rate (-s) and not by the SDR sample rate!
If you don't get this nice peak, but maybe several peaks, you might have the input over-driven.
If you don't get nice peaks, but maybe several peaks, you might over-driven the input.
Note that the peak will spread by the frequency deviation, so the peak might look noisy on the top.
If the peak is quite low, check the input gain.
</p>

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@ -277,6 +277,63 @@ It can be used to check a headset.
Everything that is spoken into the microphone should appear on the headphone.
</p>
<p class="toppic">
On-screen displays
</p>
<center><img src="display-wave.png"/></center>
<p>
Essentially for monitoring the input level is the 'w' key.
You will get an ASCII art plot of received audio signal.
Press 'w' again to turn off this view.
</p>
<center><img src="display-measurements.png"/></center>
<p>
To check measurements like input level and quality, press the 'm' key.
You will get an ASCII art plot of differen bar graphs.
They show tone / frame level and quality.
The green bar shows the current level.
The yellow marker shows the last/peak/average level.
The light blue marker shows the target level.
Some measurement like RF level, frequency offset and peak deviation are only available with SDR.
Press 'm' again to turn off this view.
</p>
<center><img src="display-iq.png"/></center>
<p>
Only works with SDR:
You can monitor IQ data by pressing 'q' key.
You will get an ASCII art plot of received IQ data.
Press 'q' again and you will get a logarithmic view of IQ vectors.
Press 'q' again to turn off this view.
Please monitor this view when the phone tries to call or register.
If the dots are yellow, or red, the received signal may overdrive the ADC.
Especially when the linear view shows a deformed circle (or even rectangle), reduce RX level.
</p>
<center><img src="display-spectrum.png"/></center>
<p>
Only works with SDR:
Press 's' to get an ASCII art graph of received frequency spectrum.
The spectrum's bandwidth is defined by the sample rate (-s) and not by the SDR sample rate!
If you don't get nice peaks, but maybe several peaks, you might over-driven the input.
Note that the peak will spread by the frequency deviation, so the peak might look noisy on the top.
If the peak is quite low, check the input gain.
Press 's' again to turn off this view.
</p>
<center><img src="display-status.png"/></center>
<p>
Current transceiver and call state can be viewed by pressing 'c' key.
Press 'c' again to turn off this view.
</p>
<hr><center>[<a href="index.html">Back to main page</a>]</center><hr>
</td></tr></table></center>
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