Decoding Analog Signals with PCM/QAM - Help Needed

  • Thread starter Thread starter IT_GE
  • Start date Start date
  • Tags Tags
    Analog Digital
AI Thread Summary
The discussion focuses on converting analog signals to digital formats using PCM and QAM for decoding fax information. The user is recording analog signals via a phone line and seeks algorithms to demodulate these signals into digital formats like TIFF or BMP. Despite having some documentation on fax modulation, the user struggles to extract usable data from the recorded WAV files. Participants suggest that a deeper understanding of digital signal processing is necessary and recommend looking for specific resources online. Ultimately, the user is looking for practical guidance to develop a program that integrates with their existing system for decoding fax data.
IT_GE
Messages
8
Reaction score
0
from analog to digital(PCM/QAM)

I want to convert analog to digital.

I am recording analog signals in my firm and i want to make a programm witch helps me to decode fax informations.

if you know how to decode this analog signals witch is modulated with PCM/QAM, please help me.
 
Engineering news on Phys.org
Obviously, you'll need an ADC and a DSP. If you could tell us more about your system, we can be more helpful. Of course, you might want to consider hiring a contractor with the appropriate skills.

- Warren
 
ok

now i have connected with line in cable to the my phone cable. i am sending faxes to another line and recording it's analog signals with sound forge.

i have documentation about qam but i can't get any digits from this vawe files.

i am searching algorithm how to demodulate analog signals and get fax data as tiff, bmp or jpg or another fortmat
 
This product might help you: http://www.vectronics.com/vectronics/products.php?prodid=VEC-1613
 
Last edited:
no
I not need any products.
I want to write a program which will be integrated in my system.
 
i am parallel connected to the analog phone line witch is using to send/receive faxes.
i am recording this analog signals in vawe/pcm format.
i know how fax protocol is working, but i don't know how modulates digital signals to analog... and how to demodulate analog signals and get digital data.

i am askign you...
if you have any documentation about fax modulation or you can help me, please make it now.
 
IT_GE:

You're essentially asking us to give you a university-level education on signals and digital signal processing. It's quite simply outside the bounds of what we can teach you on an online forum. I suggest buying some books, or taking some classes. You need to learn quite a bit before you can do what you're trying to do.

- Warren
 
ok

chroot

i know how analog and digital signals work.

but i need documentation about fax modulation.

i can't find this documentation.

if you know where i can get this documentation please tel me.
 
IT_GE:
Goto Google and look under Facsimile Coding Schemes
I think you will find all the information you need.
 
  • #10
IT_GE:
if you know how to decode this analog signals witch is modulated with PCM/QAM, please help me.
-------------------------------------------------------------
PCM=PULSE CODE MODULATION
QAM=QUADRATURE AMPLITUTE MODULATION
A FAX MODEM CONTAINS ALL THE HARDWARE TO CONVERT THE
SIGNALS FROM ANALOGUE TO DIGITAL,use a programming language
to capture-decode-manipulate-present digital data,there's very little
decoding left to do,just get fax protocal details to give an idea what
you have to do with the software
 
  • #11
i suggest you buy from a vendor that provides you with complete
tools--hardware-drivers-libs and make sure your programming language
is compatible with those
 
  • #12
ok
thank
i know what is qam and pcm.
i have files witch is recorded as pcm wav file.
i know fax is using qam for modulation/demodulation of digital data to/from analog sygnal.
i know how to get tiff images from the digital data, but i don't know how to connvert this analog signals.
i have documentation about modulation, but it not like the really situation and not works properly.
i searched this info in google but no answer.
 
Back
Top