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Andreas Eversberg
2016-10-02 09:01:12 +02:00
parent b07509cf2d
commit 50e311590a
3 changed files with 17 additions and 6 deletions
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docs/amps.html
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@@ -23,6 +23,12 @@ History
<p>
*TBD*
The Advanced Mobile Phone Service (AMPS) was an analog cellular mobile phone system developed by Bell Labs.
From 1968 to 1983 the Bell Labs worked out the system, while Motorola was developing the cellular phone.
Dr. Martin Cooper produced the first handheld phone "DynaTAC8000x", the famous Brick Phone.
</p>
<center><img src="amps-dynatac.jpg"/></center>
@@ -61,8 +67,8 @@ History
<p>
To reduce radio noise, a syllabic compandor is used on both ends.
This compresses the audio level dynamics by 2.
An audio level of 25% is raised to 50% by the compressor and lowered to 25% by the expandor.
A radio noise floor of 10% would be reduced to 1% by the expandor.
An audio level of 25% is raised to 50% by the compressor and lowered to 25% by the expander.
A radio noise floor of 10% would be reduced to 1% by the expander.
</p>
<p class="toppic">