Questions tagged [rf]
Short for Radio Frequency, i.e. frequencies at which radiation (intentional or not) plays a role. Typically associated with wireless communications, but also relevant for high-speed PCB design.
4,233 questions
3
votes
1
answer
58
views
Why does my Clapp oscillator with a varactor diode have this problem?
I am trying to make a voltage controlled Clapp oscillator but it seems to have this weird behavior I can't fix. And I don't understand why it has this issue. At low voltages for the varactors it seems ...
- 31
2
votes
2
answers
113
views
High-Frequency Sine Wave Amplifier Design - 600mVpp to 360Vpp (100 kHz - 1.1 MHz)
I'm designing a circuit to amplify a sine wave signal from 600mVpp to 360Vpp.
Frequency Range: 100 kHz to 1.1 MHz.
Total Voltage Gain: 360Vp-p / 0.6Vp-p = 600V/V.
Load: Primarily a 2pF capacitor.
...
- 389
0
votes
2
answers
131
views
How Does a Faraday Cage Not Radiate?
I am confused at how a Faraday cage can shield enclosed electronics without becoming an antenna.
Situation 'A': Consider a particle inside an ungrounded metallic Faraday cage whose charge oscillates ...
- 873
0
votes
0
answers
59
views
DAC output power calculation
I’m looking to use the high speed DAC DAC linked here, but am confused about what the expected output power when measuring in a 100 ohm load. So I see on page 14 the datasheet gives a power of 1.4 dbm ...
- 353
0
votes
1
answer
68
views
NFC vs RFID: want to clarify the basic working principle
I am getting confused and overwhelmed by all the information about communication protocols etc. when I want to just clarify the basic physics.
NFC: From what I can tell it's just basic inductive ...
0
votes
2
answers
102
views
How can I estimate the approximate received radio power or signal strength based on limited data?
I asked this question on amateur radio here and was advised to ask on the electrical engineering stack.
I am working on a paper that requires to measure a sort of access/exposure of each municipality ...
- 11
-2
votes
1
answer
70
views
SKY65900-11 Input level
I wanted to use SKY65900-11 2.4-2.5 GHz +28 dBm WLAN Power Amplifier, but when I checked its datasheet, it didn't mention the allowed input value. Has anyone worked with this IC?if YES. So how you ...
-1
votes
0
answers
54
views
ID-12LA RFID Module is unresponsive
I recently bought a few of these modules (ID-12LA), thinking it would be easy to setup and utilize. I have not been able to get it to work. At first, I bought a pair from Sparkfun and after much ...
0
votes
0
answers
43
views
How to control PA and LNA for FEM in custom RF module?
I am working on a custom RF module. This is my first experience. If you know of a book or resource on this subject, I would appreciate your guidance. So far I want to use an SOC with built in RF (ESP)....
1
vote
1
answer
54
views
Impedance and via fence for BLE antenna feed on nRF52805 flex PCB
I’m designing a BLE temperature sensor using Nordic’s nRF52805 (WLCSP) and a Johanson 2.4 GHz antenna, built on a flexible CopperFlex PCB (JLCPCB).
The layout has a short feed line between the ...
- 191
0
votes
0
answers
59
views
Clearance for BLE Chip Antenna
I'm new to PCB design and I'm working on a very small board that requires a 2.4GHz antenna for BLE. I am very restricted as to where I can place the antenna due to buttons and LCD pad strips that can'...
- 11
0
votes
1
answer
81
views
Can MIMO function properly if RF radios are connected to an RF transceiver via coaxial cables?
My team is developing a simulator to test how degraded RF network conditions affect our Silvus MANET radios. We have a JFW RF Transceiver which acts as a sort of hub, and allows us to connect each ...
- 11
3
votes
1
answer
422
views
Why do some car key fobs use two frequencies?
Im trying to understand key fobs a bit better and to my knowledge there are systems which utilize 2 frequencies (LF and UHF) https://en.wikipedia.org/wiki/Smart_key#Keyless_Go. The key fob receives ...
- 258
-1
votes
0
answers
74
views
CD54HC4046A VCO
I have a working phase detector out of the CD54HC4046A using a 12MHz crystal, but I cannot get the VCO to work with R1 = 5.7k Ohm and C1-C2= 47pF and VCOin = 2V using a voltage divider from my 5V ...
- 21
1
vote
1
answer
164
views
How to get rid of unwanted frequencies after mixing
I'm pretty newbie and I managed to make a carrier F0 over 100 MHz modulated by my signal F1 around 10 kHz.
I mixed both signals, but when I looked across the band, I got multiples of F1. The frequency ...
- 163