Tagged Questions
2
votes
1answer
156 views
Why is the loaded Q of a critically coupled two-resonator circuit approximately equal to 0.707 times the loaded Q of one of its resonators?
From RF Circuit Design by Christopher Bowick (page 32 bottom of the page left column):
The loaded Q of a critically coupled two-resonator circuit is
approximately equal to 0.707 times the loaded ...
3
votes
1answer
333 views
PCB stub antenna impedance matching
I'm about to design a 433MHz transceiver and found a nice reference design using the TRC105 and the RF3608D SAW Filter.
Before designing the circuit I wanted to understand the impedance matching in ...
3
votes
1answer
92 views
What EMC considerations need to be made with RF bias-t with 3-4A of current consumption?
After getting a great answer on how to couple a signal on to a DC line, I wonder what EMC considerations that has to be done with using a bias-T circuit used for communications with a ~130kHz QPSK ...
1
vote
2answers
414 views
Design a 1 GHz lowpass filter
I want to design a 1 GHz low-pass filter. I have tried to find a COTS lowpass filter at such high frequencies but I can't find one.
Hence, I have decided to design one using microstrip lines. So, ...
4
votes
2answers
564 views
100W Low Pass Filter
Currently I have a 60W amplifier for the 400-500MHZ band with a 50Ω impedance. In order to prevent jamming other frequencies I will need a low pass filter to block any frequencies above 500MHZ. I just ...
1
vote
1answer
168 views
Wideband Passband RF filter
I require a passband filter with
bandwidth of 500 MHz.
4 GHz central frequency.
minimize the attenuation of the signal (but there is no restriction on this as I am going to use power amplifiers ...
5
votes
5answers
1k views
Circuit to remove noise from digital communication line
Carrying on further from my previous post and drilling down to specifics, I am trying to figure out the right way to implement "glitch remover", or "noise remover", using electronics (i.e. not in ...
3
votes
4answers
734 views
How to terminate 50 ohm transmission line without drawing DC
I am sending a 10 MB/sec digital data stream by amplitude moduating a infrared quantum cascade laser. The laser requires a hefty bias of about half an amp (which drops about 8.5 volts across the ...
2
votes
1answer
253 views
How to filter RF signals to get the average value?
I am designing a system that will use a phase frequency detector with 400-450 MHz signals. There is a filter required on the output of the phase frequency detector in order to obtain an average value ...
3
votes
1answer
162 views
How to buy difficult-to-find electronic parts?
A RF receiver project I'm working on calls for a very specific SAW bandpass filter. I've checked all the usual sources here in the US (Jameco, Mouser, Digikey, Newark, etc) without success. What I'm ...
3
votes
3answers
518 views
How to approach designing a 30GHz bandpass filter?
How would one approach designing bandpass filters in the 3GHz - 30GHz range, each with ~2.4GHz bandwidth, for a 50Ω spectrum analyzer or sampling oscilloscope? I've learned how to implement some ...
37
votes
5answers
2k views
What is impedance?
This is presented as both a resource for the community and a learning experience for myself. I have just enough knowledge of the subject to get myself into trouble, but I don't have the best grasp of ...
