Decoding Analog Signals with PCM/QAM - Help Needed

In summary, you want to convert analog fax signals into digital form so that you can more easily and effectively decode and manipulate the data. You have connected your phone line to your computer and are sending faxes and recording the analog signals in sound forge. You are looking for information on fax modulation, but you have not been able to find any. You suggest buying books or classes to help you learn more.
  • #1
IT_GE
8
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.
 
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  • #2
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
 
  • #3
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
 
  • #4
This product might help you: http://www.vectronics.com/vectronics/products.php?prodid=VEC-1613
 
Last edited:
  • #5
no
I not need any products.
I want to write a program which will be integrated in my system.
 
  • #6
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.
 
  • #7
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
 
  • #8
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.
 
  • #9
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.
 

1. What is the purpose of decoding analog signals with PCM/QAM?

The purpose of decoding analog signals with PCM/QAM is to convert analog signals into digital signals for more efficient and accurate transmission and processing. This allows for clearer and more reliable communication and data transfer.

2. How does PCM work in decoding analog signals?

PCM (Pulse Code Modulation) works by sampling the amplitude of an analog signal at regular intervals and then quantizing and encoding the amplitude values into digital codes. These codes can then be transmitted and decoded back into analog signals at the receiving end.

3. What is the role of QAM in decoding analog signals?

QAM (Quadrature Amplitude Modulation) is a technique that combines two amplitude-modulated signals into a single signal. In decoding analog signals, QAM is used to modulate the digital codes from PCM onto a carrier signal, which can then be transmitted over a communication channel.

4. What are the benefits of decoding analog signals with PCM/QAM?

Decoding analog signals with PCM/QAM offers several benefits, including improved signal quality, reduced noise and interference, and increased data transfer speeds. It also allows for the integration of multiple signals and the ability to transmit over longer distances without losing signal strength.

5. How is decoding analog signals with PCM/QAM different from other methods?

Decoding analog signals with PCM/QAM is different from other methods in that it uses a combination of sampling, quantization, and modulation techniques to convert analog signals into digital codes. Other methods, such as frequency modulation or amplitude modulation, do not involve the conversion of analog signals into digital codes and rely solely on modulating the signal for transmission.

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