Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

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.

Note that RF radiation is regulated in most, if not all, countries.

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What is the standing wave ratio (SWR)?

In rf electronics, we often characterize a component or antenna by its standing wave ratio (SWR). What is the definition of this parameter and how does it affect a circuit? The motivation for this question is that while answering another question,…
The Photon
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Can you use inductors for emitter degeneration?

Common emitter amplifiers often use resistors in their source and collector but I have been thinking, they consume power. In RF applications, would it be possible to achieve the same effect with inductors instead?
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RF vs. audio of the same frequency

From an article by an engineer at Cisco Systems: An RF signal can have the same frequency as a sound wave, and most people can hear a 5 kHz audio tone. No one can hear a 5 kHz RF signal. Why not?
user167734
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what are tuning dots and how to effectively use them

I've come across some template designs that have tuning dots included for RF matching. Unfortunately they are using a different dielectric than I am. What are the basic principles of tuning dots (theoretical to purely mathematical would be great),…
Legen Diary
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What are these rectangular sidebands on my local FM radio station?

I recently bought an inexpensive USB software-defined radio dongle, and have been poking around my local spectrum: The above image is one of the local FM radio stations (88.7 Mhz, to be specific). I am wondering what the large, rectangular…
Connor Wolf
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Why does holding my car's RF remote to my head extend its range?

I'm in my parking lot and just a little too far from my car for the remote to work... But if I hold the remote up to my chin, and then suddenly it works. It sounds dumb until you try it, but it definitely works, with lots of different remotes/cars.…
Adam Berkan
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900 MHz vs 433 MHz for urban environments

At ranges of a few hundred meters, will there be an appreciable difference in performance (ie range, bit rate) between 900 MHz and 433 MHz for digital applications in an urban environment? Forgot to mention, I've read that some frequency ranges are…
Dan
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Implementing a network of RF receiver/transmitters

I should make it clear tha I'm not an electronics buff, although I did do Electronics for my A-Levels (and got an A) I have 2 cats named Ollie and Tiggy. I don't want them going towards the road for obvious reasons. My house is surrounded mostly by…
hedgehog90
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What is the best way to debug a radio?

I am currently programming / configuring an Atmel AT86RF233 radio and trying to get it to communicate with an digi xbee. So far I have set the following fields on the Atmel radio: extended address pan ID operating channel not coordinator (i.e.…
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Downconversion using frequency divider vs. mixer

Let's say you have a 1 GHz signal that you want to receive and demodulate. I am familiar with the superheterodyne receiver, where an LO of 1 GHz is mixed with the RF signal, and the output is then used. On the other hand, it seems that we can also…
student1
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what is transparent operation on rf?

Whenever I am searching Rf module, I have seen transparent operation on some module.I have searched meaning of transparent operation, but I could not find anything. My questions are What is the transparent operation ? Why is it used in RF module ?…
user5140
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Is the wrong antenna worse than no antenna?

I have a wireless transceiver. It is programmable to allow both transmit and receive from 1-1000MHz with FSK or ASK. The PCB and components have been chosen for transmission at 433MHz. Another PCB variant is available, tuned for 915MHz. If I attempt…
Toby Jaffey
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Actual Implementation of a Multiplier

In school I have learned in both systems and communication about multiplication blocks. I have been taught that these blocks create a sum and difference frequency and can be filtered to get just the sum or the difference. What I am wondering is how…
user3272
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Buying RF metal shields

Where can I find those metal shield cans that you can solder directly on a pcb for EMI shielding? Just like the ones on the back of XBee modules? I'm not having any luck searching on farnell, perhaps with the wrong keywords, or maybe it's not a…
cksa361
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Why do cables that carry RF have 2 leads

I just got a ham radio license, and I am trying to figure out the mystery of RF. From the output on your transceiver to an antenna or an RF amp, there is a 2 lead coax cable. If antennas only have one wire sticking up, what is the point of a 2-lead…
skyler
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