recovering audio signal from PCM stream

[Tirmizi]

Hi i want to recover an audio signal from a PCM stream which is being transmitted by a third party  system  on RS 422 wires. the only information i have about the PCM stream is

sampling freq              16kHz

bits                                 8

quantization tech          u Law qunatization

over all PCM data transmmison vlaue mentioned  is 2.408 M bits

please suggest me if it is doable or not . further more suggest the proper NI hardware as  well as software modules required to achive this. will NI 9401 do this job

[AirFrantz]

Tirmizi,

I think it may be possible.  You could not use a 9401 but if you had a USB to RS-422 converter you could probably read the PCM data into LabVIEW using VISA functions.

If you can successfully import your data to LabVIEW, I found a similar forum post that explains the functions in LabVIEW to use to create a .wav file and what you can do with it:

http://forums.ni.com/t5/LabVIEW/Raw-PCM-to-WAV/m-p/2739674

Hope this helps!

[Tirmizi]

the PCM stream contains not only audio samples but also samples of morse code as well as other information. the system manual of that device donot share the packet information contains in PCM stream like which bits belong to audio and which one to morse.  is PCM packets information is  standard or it is upto the vendor to make it properitory. if it is properitory then i have to tap the data and throught hit and trials find out the audio packets in stream

[AirFrantz]

Because PCM is a form of modulation, any kind of data could be stored in this way so I believe it's up to the vendor to decide on the particular format.  I'm not very familiar with PCM, however, so hopefully someone can jump in here with some more information for you.

[vs_2014]

Hi,

I have a question regarding the configuration of the PCM2706 using as output an amplifier (namely TPA3123).

I want to know what is the configuration of passive components that is recommended use for output: VoutR & VoutL. I checked for some examples in datasheets and I didn't find coherence in some passive components:

Polarity of the capacitors and discharge resistors.

Can anyone help me? I need to know recommended resistors values and capacitors polarity configuration.

Thank you

[Dennis_Knutson]

Your question has nothing to do with the original post. Does it have anything to do with any NI hardware or software?

[vs_2014]

Do you have simulation models of these two components for Multisim/Ultiboard?

[Dennis_Knutson]

Multisim questions should be posted to that board.