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fireplus
Joined: 31 Oct 2003
Posts: 198
Helped: 5
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 28 Mar 2006 22:10 voic over ip chips ? |
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hi,
i need to design a project based on voice over ip and i need some one to help me to find chips i need to start working with this project
thanks for every body need to help
Fire in The Wire 
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throwaway18
Joined: 09 Jun 2005
Posts: 553
Helped: 73
Location: Kent, UK
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| 28 Mar 2006 23:24 voic over ip chips ? |
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You want to make a device like a telephone that plugs into
an ethernet port? You want to make it all yourself from individual
parts rarther than take the easy way out and use an embedded PC?
You need to descide if you want your device to be compatable
with one of the existing VOIP systems.
You need an internet protocol stack (software that handles
sending and receiving data over ip), voice compression and
decompression algorithms if you want it to work efficiently
over the internet, echo cancelation if you want it to
work with a loudspeaker rarther than just an earpiece
and an ethernet interface.
That means you need a resonably fast processor.
You can look at embedded linux which will let you use a
lot of existing software. You can look for a processor
with an IP stack and an ethernet interface.
Or you can choose any general purpose processor with
enough processing power and memory and a seperate ethernet
chip and spend six months full time working on the software.
You need a display. Choose an LCD module, a two line LCD
module using a HD44780 controller is a common choice
for projects.
You need a microphone and a preamplifier. At minimum a
general purpose opamp will do. An analog compressor
circuit may help.
You need an ADC. You may choose a DSP processor with a
built in ADC or you can choose from hundreds of chips
depending on what performance you want.
You need a DAC for the audio output. If you use an seperate chip
I'd favour a high end DAC designed for audio with some buffering
so you don't have to do the sample timing in your processor.
Last edited by throwaway18 on 29 Mar 2006 17:47; edited 1 time in total |
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fireplus
Joined: 31 Oct 2003
Posts: 198
Helped: 5
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| 29 Mar 2006 9:03 Re: voic over ip chips ? |
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thanks a lot ,
could you please provide names and llinks to chips and solutions
Fire in The Wire
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pool_77
Joined: 08 Aug 2001
Posts: 215
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| 30 Mar 2006 19:48 Re: voic over ip chips ? |
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Easier start is with Centrality PA1688
Nearly all source is available.
Cheap solution
Many designs is also on PSB21553 from infineon
Pool_77
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