Sayings.

I thought this is a good quote that I got from a forwarding mail:

Wake up in the morning with two simple choices:

1. Go back to sleep and dream.
2. Wake up and chase those dreams.


Yes. Dream and work towards fulfilling your dreams.

Follow up of my previous blog

OK. I thought I should give a shot to the standard observations that I posted in my previous blog.

I posted these two things:
1. Increasing the attenuation by 10dB increases the noise level by 10dB.
2. Increasing the RBW by 10dB also increases the noise level by 10dB.

The first observation was right with my experiment with the Rohde and Schwarz FSQ8.

For the second one, what I have seen on this million dollar baby is something different.

I terminated the RF input with a 50 ohm resistance and found the noise level increased to around 6dB instead of 10dB for a 10dB change of RBW at 2382MHz to 2482 MHz.

I started with 50MHz RBW (Max that I could go on the FSQ 8) and saw about -75dBm noise level. I made sure my VBW is auto mode.

When I reduced the RBW to 5MHz, I saw the noise floor is about -80dBm.

I went ahead and reduced the RBW further down to 500Khz and then I saw the noise floor dropping down to -85dBm.

So, for a factor of 100 decrease in frequency, the Noise floor reduces by 10dB.

10 log(50/5) = 10dB change in the frequency, there is a 5dB change in the noise floor.

For 10 log(50/.5) = 20dB change in the frequency, there is a 10dB change in the noise floor.

The detector I was using was an rms detector.

I shall continue to find out the math behind this theory and get back in my next blog.

so long..

Spectrum Analyzer Basics

Yes!! I am back to my blogging.

Found a nice link for getting the info on Spectrum Analyzers.
http://www.spectrum-analyzer.info/Spectrum_Intro.aspx



Interesting to find out these things:

1. Increasing the attenuation by 10dB increases the noise level by 10dB.
2. Increasing the RBW by 10dB also increases the noise level by 10dB.


Check out Page 15 from this link:

http://www.us.anritsu.com/downloads/files/SpectrumAnalyzer_EE1200.pdf

I think this is one of the ways of finding out if IM products are coming out of the DUT or from the Spectrum Analyzer itself.

Increase the attenuation by 10dB (the noise level increases by 10dB) and

if the harmonics' level remain constant, the harmonics are from the DUT.

If the harmonics level is reduced or disappeared in the noise, then it is the spectrum analyzers IM product. If decreases by 20dB, then it is second order harmonic and if decreased by 30dB, it is a third order harmonic.


Cool things going on inside the equipment.

I guess most of the talk regarding a spectrum analyzer involve:

Spurious Frequencies (Image noise and Half IF), IM products (IP2, IP3), Linearity of the mixers and the associated blocking filters.

ZIF or DCR receivers have some advantages but have to trade other parameters like sensitivity, selectivity and AGC to name a few.

Second Blog and Intro to Systems

OK. I just remembered that I have a blog after going through an article on cnn.com.

I thought I should atleast write something in my blogspace. So, let me talk about some interesting things.


I started to develop more interest on the PA inside a communication system. Ordered a book on ebay, RF Design by Hayward, recommended by some folks from the ARRL group.

The concept of IF, ZIF, NF, intermodulation are dealt in this book.

Still trying to understand the enigma inside the communication system's RF chain and all the components' complexity and the tradeoff's the systems enginners make in designing an effective communication system.

I shall update on this as I read more chapters from this book. Hopefully most of my queries will be quelled with this book.


Catch me later.

My first blog

Yes!!! This is my first blog.