Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

How to model a stream up conversion with BW of 0.5 MHz?

Status
Not open for further replies.
Ahmed Alaa

Ahmed Alaa

Full Member level 5
Joined
Jul 22, 2009
Messages
317
Helped
61
Reputation
136
Reaction score
44
Trophy points
1,318
Location
Egypt
Activity points
2,965
Dear all,

Assume we have a bit stream [1 0 1 1 0 1 0 1 1 0 0 0 1 1] represents bits with a duration of 1 microseconds, thus its baseband BW = 0.5 MHz, if we want to model this stream's upconversion, we'll multiply by an 0.5 MHz carrier (minimum possible carrier freq). Does this mean that we'll multiply the above stream by [1 -1 1 -1 1 -1 1 -1 1 -1 1 -1 ...] ? I am arguing my boss in that :smile:

Thanks,
Ahmed
 

Re: Up conversion

He says you must have some carrier cycles within one bit duration, otherwise you don't have a carrier. This confuses me because the problem is very basic and I'm sure I'm right.. I think his view is that when using the stream [1 -1 1 -1 1 -1 ...] we'll have half a cycle per bit duration, which means the spectrum starts sharply from zero till 2B where B is the baseband BW.

btw, why 2*0.5 MHz, this should be the sampling freq I think, but to avoid spectral overlapping, the minimum carrier = Baseband BW, right ?
 

Re: Up conversion

for baseband, Fs = BW but for passband Fs = 2*BW with rectangular pulse shaping, if you used ideal sinc function pulse shaping, I think you'd need Fs = BW for passband.

---------- Post added at 04:20 PM ---------- Previous post was at 04:18 PM ----------
Ahmed Alaa said:
He says you must have some carrier cycles within one bit duration, otherwise you don't have a carrier. This confuses me \
Click to expand...

1 cycle is enough for sinc pulse shaping but 2 for rectangular, which is what you seem to be using.

Maybe you should ask him for more info/explanation.
 
Re: Up conversion

I am using an array with each element represent a sample, this corresponds to a sinc not rect. Thank you, I didn't think about that before !
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top