Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
I've been pretty AWOL from this site but need to reconnect with the wealth of folks willing to help.
From what I understand a process is made up of a single or multiple threads, correct? Can multiple threads run concurrently or are they all scheduled at a fast enough rate so as to seems like...
I'm a newbie to embedded system design and need some help understanding how certain concepts affect the overall system design. I'm in learning mode as pat of this team so I'mnot expert. So expect stupid questions. :) I'm not here to have people tell me how to do a design since that is the job of...
I am using an Avago LNA that according to the datasheet is unconditionally stable.
See link: Ultra Low Noise, High Linearity Active Bias Low Noise Amplifier
I have a test board and populated the components for low NF. If I am only interested in a specific band and the stability factor states...
I have a pulse generator that only does 50 ohm out and a switch circuit that has an high impedance input. I see that this is a problem but would like to know how to have a quick fix.
Is it possible just to have a 50 ohm resistor to ground at the input? If not then what do I do?
Avago shows that their LNA is stable even below 450MHz in their data sheet - page 8. I looked at their K-factor calculations which should be based on their S-parameters.
Did you look at the s-parameters and saw that it was unstable?
I have a question regarding distribution transformer mounted on a pole (neighborhood), how are more than one house wired to a distribution transformer on the pole? Are they all connected to the 3 wire terminals?
Some details on this would be great. Links are welcome.
Can you help in getting the component vales for this part at 300MHz?
According to the data sheet:
**broken link removed**
"Essentially, C1 & C2 at the RFin & RFout are DC blocking capacitors. L1 is input match for noise figure and L2 is output match for OIP3. C3, C4, & C6 are bypass...
I am looking into using this Avago LNA and they show an application note for 900MHz (see link) where they show the component values.
**broken link removed**
How can I use the exact same design at 300MHz? I don't know how to do it but I image that I have to do some sort of...
Attached is a jpg of my control circuit that goes to the switch. It will do 0 & -5V output differential from2.5 ns rise and fall 0-5V or 0-2.5V from pulse generator.
What do you think? 50Ohm setting or 1kOhm setting?
Thanks for the reply.
I plan to use an Agilent 81111A Pulse Generator (with complementary outputs) to provide the control to my drive circuit for my SPDT switch. The SPDT switch can be found here:
Pulse Generator here...
I was thinking about impedance calculations and inductance. I probably mixed it all up. Forget I said that.
I have two coils that are in close proximity to each other and one port is on one coil and the other port (port 2) is on the other coil. I got 2-port S-parameters. Is there a similar way...
I figured as much but was just making sure.
Is it possible to get mutual inductance between two coils using 2-port s-parameters? Instead of dividing by 2*pi*f should I multiply? If I'm wrong then what is the proper procedure?
Thanks for the help.
Is it possible to get these characteristics of a RF Switch if you have the 2-port s-parameters when the switch is open and closed?
If so, can someone provide the equations or link me to them?
I added some stuff to the first post.
I wish I could use a absorptive switch. So we need really fast switching speed and the switch we have has <1ns switch time. Bad news is that the document that I have has no information on it being reflective or absorptive. Just looking at it I am assuming...
Thanks for the reference. Good read.
G0HZU, thanks for the continued help.
I have another question which plays off this fact that my impedance changes significant as I move away from 300MHz. Then I open the switch on the antenna and now looking into the LNA is high kOhms. Do I have to...
So I had a narrowband antenna, Q approx equal to 20 and my frequency is 300 MHz. My impedance at 300MHz is 60.95 - j45.75. BUT, my impedance changes significantly when I move off 300MHz.
My issue is that the LNA will see high kOhms when I open a switch on the antenna (receive antenna).
I agree with what your saying and no your not taking this thread off course. I like the discussion. It helps me think.
My issue is that I did not design the antenna and it is known that the Q is already so high on the antenna. Your comment earlier about the S11 looking like a narrowband filter...
So you bascially got it. There is a switch on the antenna that opens it and closes the loop. The antenna goes into an LNA. There is no rf filter or duplexer.
The Q coming out of the antenna is already high (relatively speaking). I just expect that the broadband matching can help.
It is looking into a switch that switches a network in and out. The S11 is when the switch is closed.
Can you elaborate on the your last two sentences a little please? Thanks.
Any ideas in getting the required BW, i.e. lower Q? I was thinking about adding some resistance to get the Q down a...