RF over fiber is where you modulate an RF signal onto the light beam and thus transmit it at a lower loss over a long distance. It is an analog usage as opposed to a digital one as used in data transmission such as an ethernet extender. I have found Read more…
If you plot a curve of constant ratio of Impedance / Resistance you will see that they plot out football shaped areas on the Smith Chart. See below: If you are attempting to design the widest band match possible then do not violate the initial footbal in which your load Read more…
If your 50 ohm microstrip transmission line varies somewhat in impedance when you are connecting 2 50 Ohm elements together you can use a 1/2 wave length of line in between the blocks if space is available and the design is narrow band. What will happen in a full spin around Read more…
WinSmith is a Smith chart match calculating program. The starting point is 8 – j16 ohms @ 915MHz. Both the blue and the green curves start at this point at the lower left of the curves. Click on the image to see a bigger version What is interesting about the Read more…
Research Links Microwaves101: Filling Factor The question arose given a fixed microstrip transmission line characteristic impedance how does the percentage of the field in the substrate change? This is called the filling factor: Keff=ER*FF+1x(1-FF) It is the fraction of the field in the substrate. I calculated the following values: FF=(Keff-1)/(ER-1) Dk=4 Read more…
Research Links GE Phoenix flashing tool KGLNE is Bob Starr the Eagle PCB layout guy. Google: GE Phoenix packet radio eBay: GE Phoenix radio
MiniCircuits has a bi phase electronic attenuator that uses a PIN diode ring in what is normally a balance mixer configuration. They range from 8 to 23 US Dollars. Research Links Google: bi phase attenuator site:minicircuits.com Comparison of PIN ring with standard Schotky diode ring mixer that shows linearity is much Read more…
Broadcom is not very good at putting out data sheets on their parts. My first line of interest is their point to point radio IC solutions. Research Links Point to Point RF/Microwave Backhaul solutions Baseband processing to bits BroadCom product line overview PDFp Backhaul / Point to Point Radio Read more…
Research Links Gnu Radio – software defined radio project HackRF – a kickstarter project to make hardware that will work with Gnu radio Gnu radio on youtube CGRAN – Comprehensive GNU Radio Archive Network – Project archive USRP Schematics – wikipedia: USRP Doxygen of GnuRadio C API Example Project using Read more…
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