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Cheap solution for 4 channel pcm combo codec

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Newbie level 6
Feb 10, 2006
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I'm finding a good and cheap solution in multichannel pcm combo codec, like ST's STLC5046.
Do anybody knows anything about the options on this kind of chip?

Mauro Casse

pcm codec

I never take into acount St microelectronics Telecommunication component!
I dont recomend it .
I think other company's ICs such as Infineon is much better.

call id pcm codec

Are you asking about the options of the STLC5046 chip or about multichannel codecs in general? There are a lot of Quad combos available also from infineon, Si Labs, Legerity and others. If you need them the modern multichannel DSP codecs have interesting features like programmable termination impedances programmable frequency responce programmable transhybrid balance, adaptive transhybrid balance tone generation and detection including DTMF and for the more advanced ones features like echo cancellers, line testing, line measurements and others. The most advanced have dedicated CODEC-SLIC solutions.

+why to use pcm companding

I'm asking about codecs in general.
Thanks for your help


Mauro Casse

codec sortie pcm + dtmf

ST product will expire as soon as posible.
it's life period is small.
and ST stop producing any [communication] chip without previus notice!
I designed new circuit with new generation combo STLC3040 for 4-5 years age.
and when we want to offer it (to buy), i surprised.
because its production were stopped.
and another intresting stuf is that, ST dont remove it's datasheet from it's site for 3-5 mounth later!!!!

Davood Amerion.

dsp interface with mulaw companding

In most applications codecs are used after the Subscriber Line Interface (SLIC) and convert the 4 wire signal to PCM stream (A-law and Mu-law companding) and the PCM stream to 4wire analogue. Most modern codecs have SPI interface or GCI/IOM interface to a microprocessor. Through this interface you can program the gain at both directions the time slot assigner (selecting the transmit/receive time slots of the codec on the PCM bus) and control some digital I/O 's that are used to control the SLIC. PCM and SPI clocks are usually programmable by the user for up to 4.096MHz or more. There may be an interrupt pin with debouncing functions that monitors changes in one or more of the digital inputs per channel that are intended for off hook detection.
In more advanced designs a DSP engine is programmable to implement the termination impedance the receive and transmit frequency responce and the transhybrid balance. Software is available by the IC manufacturer to calculate the DSP coefficients. Spice is used for the modelling of the SLIC for the calculation of the coefficients. Also instead of PCM companding you can use 8 or 16 bit linear.
Tone generators may be available for call progress tones and DTMF.
The latest generation of codecs has dedicated SLIC interface IC's and all functions are programmable including line feed characteristics adjustable balanced or unbalanced ringing, charge pulse metering, DTMF and universal tone detection and generation line supervision and line testing, caller ID generators, Line Echo cancellers and more. Examples can be found at Infineon ( legerity ( and Silicon laboratories (

codec with time slots

Thank you very much, that's the info I need.

Best Regards


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