Wednesday, June 20, 2012

RF for the First Time

I met my soon to be boss two days ago, that was March 9, 2011. He is a Japanese engineer working in our company for almost 16 years already and he is now the department's manager. Early next month, April, he will join our division as our General manager. This young brilliant man is only 38 years old and have been to many countries like China, Singapore, USA, and Philippines to develop cutting edge technologies and innovative products. He is responsible in creating RF designs used in RF applications such as audio portable devices.

Having been in circuit designing for 8 years, developing multi-purpose Integrated Circuits like linear regulator, motor driver, operational amplifier, dc-dc converter, and LED driver Ics, it would be my first time to be involved in RF design.

Since last week, I was asked to develop a super buffer. So I shall be getting good IP3 and 1dB compression from my design. I have two-tone signal in my input, f1=98MHz and f2=100MHz. From the equation (f1*2)-f2 and (f2*2)-f1, I shall have 96MHz and 102MHz as my 3rd order frequencies.

Simulating the circuit, I can get the 3rd order frequencies, which is shown in figure below:


To get the IP3 of the circuit, line is extended to the 3rd order graph through the 1st order line. Their intersection is the IP3, which is shown in the figure below:



To verify the data, I also get the transient response at the emitter and collector of the transistor. The transient response of the collector and emitter of the transistor is not distorted until input signal is 111dBuV.

No comments: