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Design >> RF Design >> channel selection
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Message started by aaron_do on May 28^th, 2007, 2:35am

Title: channel selection
Post by aaron_do on May 28^th, 2007, 2:35am

Hi all,

I was wondering, how does a transceiver know which channel to use? Does it just continuously sweep its channels until it picks up a signal? where would i find information like this?

thanks,
Aaron

Title: Re: channel selection
Post by didac on May 28^th, 2007, 2:46am

Hi Aaron,
It depends on the standard. On the GSM system after the access to the base station the mobile phone are assigned to a frequency and a Time Slot for receiving and transmitting, on the other hand in Bluetooth the master device rules the system with his clock(that its previously known by the slave devices when they connect to the piconet) that controls the frequency-hopping scheme, so the slave knows at which frequency it must "hear" in each instant and only has to read the header of the frame to identify if the frame is for it or is for another device. So the best thing will be to see the radio specification for your standard because each system is a world apart.
Good luck,

Title: Re: channel selection
Post by didac on Jun 2^nd, 2007, 8:04am

Hi again,
I think that you can take a look at chapter 4 of RF Microelectronics of Prof.Razavi, it explains quite well this kind of things and includes a few examples(not in depth).
PS:sorry for not giving you a reference in the previous post.

Title: Re: channel selection
Post by aaron_do on Jun 2^nd, 2007, 5:50pm

thanks, i know which book you mean

Aaron

Title: Re: channel selection
Post by loose-electron on Jun 5^th, 2007, 11:26am

Aaron:

2 hats:

IC Designer
Communication System Designer

Pick one, right? If you take your ICD hat off and put your CSD hat on, they get into the whole world of protocalls and methods.

Ever hear of things (in CSD parlance) called the PHY and MAC layers? Most of the time, ICD folks are all about the PHY layer. Physical rendering, this frequency, linearity IRN, etc etc.

Depending on the system, there are many different ways that this can happen, and it is usually defined at the MAC layer.

Jerry

Title: Re: channel selection
Post by didac on Jun 5^th, 2007, 12:18pm

Hi Jerry,
I must say that I'm a Telecommunications Engineer, so most of my education is based in protocols,math,signal processing,signal theory and this kind of things. But one of the possible specialitzations offered at my university is microelectronics and at my group(RF guys) all are from Telecommunications, no one is from Electrical and Electronic Engineering(VLSI guys and Power guys are more from this branches).
I disagree with your point of view that you must only focus on IC design or protocol(PHY,MAC and so on), I think that nowadays an engineer working in communications systems must have a mixed background and not only has to know how to read a specification given by the System Engineer. Just my opinion altough,
Regards,
Didac