Register to reply

PAM schematic or wiring diagram for Digital Communications

Share this thread:
makovx
#1
Aug9-10, 08:43 AM
P: 24
Hi. Who among you know a site where I can find a wiring diagram or schematic diagram of PAM (Pulse Amplitude Modulation)? I badly needed a diagram of it for my prototype in Digital Communications.

I've been searching for it in Google but it only gave me different diagrams and I can't tell which is which because I've never seen any PAM schematic diagram before. :(

The professor only told us that our second prototype is PAM. He only gave a brief description about what a PAM does. If I have not searched in the internet, I won't know that the meaning of PAM is Pulse Amplitude Modulation.

An article about what a PAM is, can be found in http://www.tech-faq.com/pulse-amplitude-modulation.html

I hope you can help me. Thanks!
Phys.Org News Partner Science news on Phys.org
What lit up the universe?
Sheepdogs use just two simple rules to round up large herds of sheep
Animals first flex their muscles
berkeman
#2
Aug9-10, 03:42 PM
Mentor
berkeman's Avatar
P: 41,041
Quote Quote by makovx View Post
Hi. Who among you know a site where I can find a wiring diagram or schematic diagram of PAM (Pulse Amplitude Modulation)? I badly needed a diagram of it for my prototype in Digital Communications.

I've been searching for it in Google but it only gave me different diagrams and I can't tell which is which because I've never seen any PAM schematic diagram before. :(

The professor only told us that our second prototype is PAM. He only gave a brief description about what a PAM does. If I have not searched in the internet, I won't know that the meaning of PAM is Pulse Amplitude Modulation.

An article about what a PAM is, can be found in http://www.tech-faq.com/pulse-amplitude-modulation.html

I hope you can help me. Thanks!
So to put out pulses of various amplitudes, you can use a Digital-to-Analog Converter (DAC). Probably the simplest version for you to use in your project would be an R-2R Ladder DAC. Alternately, you could use a current output mode DAC, and feed the output current into a current-to-voltage converter circuit (like with an opamp).

So that should give you some good search terms to use in your next try at Google and Wikipedia.org -- also try some of the DAC manufacturer websites like Maxim and Linear Technology, to look for application notes and tutorials.

Let us know what you find!
dlgoff
#3
Aug9-10, 06:58 PM
Sci Advisor
PF Gold
dlgoff's Avatar
P: 2,722
I was looking around earlier and got lots of hits from Google Scholar from "pulse height modulation".
http://scholar.google.com/scholar?q=...+modulation%22

makovx
#4
Aug9-10, 08:43 PM
P: 24
PAM schematic or wiring diagram for Digital Communications

Thank you for your immediate response :)

I found a pdf file about a laboratory excercise in PAM (and demodulation).
I think it's the one Im looking for.


The title is:
LAB - 3
PULSE AMPLITUDE MODULATION & DEMODULATION

and the circuit diagram is:


My problem this time is the hardware requirements.
I don't know what is the meaning of AFO, CRO and CPS.
Can you pls tell me what are these things? So that I can go to a hardware shop immediately :)

Thanks!
berkeman
#5
Aug9-10, 09:13 PM
Mentor
berkeman's Avatar
P: 41,041
From what I saw in the PAM links, the output is a series of rectangular pulses, with different amplitude rectangular pulses representing the encoded (modulated) information.

The schematic you posted looks to be an ON-OFF modulation of a sinusoidal source. From the title of the schematic/lab, it appears to be a different interpretation of PAM. Do you think that is what your lab is about?
makovx
#6
Aug9-10, 09:47 PM
P: 24
Quote Quote by berkeman View Post
From what I saw in the PAM links, the output is a series of rectangular pulses, with different amplitude rectangular pulses representing the encoded (modulated) information.
Yes, that's the PAM I exactly need.
You mean the circuit diagram I posted is a different interpretation of PAM. I see.

I'll try using the DAC you suggested then.
Thanks :)


Register to reply

Related Discussions
HDMI cable wiring schematic (what colors go where) Electrical Engineering 5
Wiring Black Box - No Diagram Electrical Engineering 2
Wiring diagram/sheep a series Advanced Physics Homework 7
Question regarding digital communications and bit error probability. Engineering, Comp Sci, & Technology Homework 0
Digital Communications textbook? Academic Guidance 2