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ADL5902 vs. AD8312 vs. AD8362 or which?

Question asked by Sophi on Nov 26, 2011
Latest reply on Nov 28, 2011 by enash

Hello-

I am new to RF, so excuse please.

 

My CDMA 3G phone has a reading in its settings that says it puts out -77 dBm or thereabouts when making or receiving a call.

While idle, it says -82 dBm.

I read similar dBm on another CDMA phone.

 

These phones operate either in the 800MHz or 1.9Ghz band according to the carrier's dox.

 

I want to design with an RF detector chip that will detect when this phone is in use and provide a signal strength output. The same chip needs to be able to detect and provide a signal strength output for the Wi-Max band (3.5 GHz).

 

In one of AD's tutorials I read that the best choice for CDMA and Wi-Max is an RMS detector rather than logarithmic. True?

 

For lower frequencies I have been using an inductor as the antenna, but have since read that an inductor will not work with GHz digital outputs.

 

Questions:

What kind of antenna is best to use?

What is the circuitry that connects this antenna?

Can I use one antenna for multiple frequencies?

Is there some documentation to read about this that goes along with the RF chips?

For a chip such as AD8362 which the output is "linear in dB", what does this mean, and do I need another chip to decode?

  -Getting a linear voltage output is most desirable simply because it seems the easiest to work with.

 

Thanks in advance.

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